PATENT DOCUMENT

Publication Number: US-11985781-B2
Application Number: US-202117446432-A
Country: US
Kind Code: B2

Title: Surface treatment for metallic components

Abstract:
A component for an electronic device can include a metal injection molded (MIM) metallic body that at least partially defines an exterior surface. The metallic body can have an average porosity less than 1% in a first region that extends from the external surface to a depth of at least 100 microns below the external surface, and an average porosity greater than 1% in a second region adjacent to the first region.

Claims:
What is claimed is: 
     
       1. A component for an electronic device, comprising:
 a metallic body at least partially defining an exterior surface; 
 the metallic body having a porosity less than 1% in a first region that extends from the external surface to a depth of at least 100 microns; and 
 the metallic body having a porosity greater than 1% in a second region adjacent to the first region, the first region having a smaller average grain size than the second region. 
 
     
     
       2. The component of  claim 1 , wherein the metallic body comprises a metal injection molded body. 
     
     
       3. The component of  claim 1 , wherein the metallic body has a porosity less than 0.5% in the first region. 
     
     
       4. The component of  claim 1 , wherein the metallic body comprises steel. 
     
     
       5. The component of  claim 1 , wherein the metallic body comprises aluminum. 
     
     
       6. The component of  claim 1 , wherein the metallic body has fewer than 1000 pores per cubic millimeter in the first region. 
     
     
       7. The component of  claim 1 , wherein the metallic body has an average pore size of less than about 3 microns in the first region in a gradient distribution. 
     
     
       8. The component of  claim 1 , wherein a portion of the exterior surface is polished. 
     
     
       9. The component of  claim 1 , wherein the exterior surface comprises an exterior surface of the electronic device. 
     
     
       10. The component of  claim 1 , wherein the component comprises a SIM tray. 
     
     
       11. A method of treating a component for an electronic device, comprising:
 contacting a surface of a metallic region the component with a tool to plastically deform the region, the tool exerting a pressure of at least 100 bar on the surface and translating across the surface at a rate of at least 1.25 meters per minute (m/min), the metallic region having a porosity less than 1%, the region extending from the external surface to a depth of at least 100 microns, and the metallic region having a smaller average grain size in the depth than below the depth; and 
 modifying a cluster of first grains positioned at the region so that at least some of the first grains are disposed between at least some second grains at the region, the first grains comprising a first phase and the second grains comprising a second, different phase. 
 
     
     
       12. The method of  claim 11 , further comprising reducing an average grain size of the first grains. 
     
     
       13. The method of  claim 11 , wherein the metallic surface comprises steel. 
     
     
       14. The method of  claim 13 , wherein the first phase comprises a sigma phase. 
     
     
       15. The method of  claim 11 , further comprising polishing the surface.

Description:
CROSS-REFERENCED TO RELATED APPLICATION(S) 
     This application claims the benefit of priority to 1) U.S. Patent Application No. 63/082,211, filed 23 Sep. 2020, and titled “SURFACE TREATMENT FOR METALLIC COMPONENTS,” 2) U.S. patent application Ser. No. 17/028,380, filed 22 Sep. 2020, and titled “SURFACE NANOGRAIN FOR IMPROVED DURABILITY OF METAL BANDS,” and U.S. Patent Application No. 62/904,055, filed 23 Sep. 2019, and titled “SURFACE NANOGRAIN FOR IMPROVED DURABILITY OF METAL BANDS,” the disclosures of which are incorporated herein by reference in their entireties. 
    
    
     FIELD 
     The present description relates generally to an electronic device. More particularly, the present description relates to enclosures for electronic devices. 
     BACKGROUND 
     Electronic devices are widespread in society and can take a variety of forms, from wristwatches to computers. Electronic devices, including portable electronic devices such as handheld phones, tablet computers, and watches, can experience contact with various surfaces during use. Further, use, transportation, and storage can exert mechanical and thermal stresses on such devices. 
     Components for these devices, such as enclosures or housings, can benefit from exhibiting different combinations of properties relating to the use of the device. A housing for a portable electronic device can have a combination of properties, such as strength, appearance, toughness, abrasion resistance, weight, corrosion resistance, thermal conductivity, and electromagnetic shielding, in order for the device to function as desired. Certain materials can provide a desired level of performance with respect to some properties, but often provide less than optimal levels of performance with respect to others. Accordingly, it can be desirable to provide a device enclosure that can include multiple materials to achieve a desired level of performance with respect to as many desired properties as possible. 
     SUMMARY 
     According to some examples of the present disclosure, a component for an electronic device can include a metallic body at least partially defining an exterior surface, the metallic body can have a porosity less than 1% in a first region that extends from the external surface to a depth of at least 100 microns below the external surface, and the metallic body can have a porosity greater than 1% in a second region adjacent to the first region. 
     In some examples, the metallic body is a metal injection molded body. The metallic body can have a porosity less than 0.5% in the first region. The metallic body can include steel. The metallic body can include aluminum. The metallic body can have fewer than 1000 pores per cubic millimeter in the first region. The metallic body can have an average pore size of less than about 3 microns in the first region. A portion of the metallic body defining the exterior surface can be polished. The exterior surface can be an exterior surface of the electronic device. The component can be a SIM tray. 
     According to some examples, a method of treating a component for an electronic device can include contacting a first metallic surface of the component with a tool to plastically deform the first metallic surface to a first desired depth, the tool exerting a pressure of at least 100 bar on the first metallic surface and translating across the first metallic surface at a rate of at least 1.25 meters per minute (m/min), contacting a polymeric surface of the component with the tool, the polymeric surface adjacent to the first metallic surface, contacting a second metallic surface of the component with the tool to plastically deform the second metallic surface to a second desired depth, the tool exerting a pressure of at least 100 bar on the second metallic surface, and translating across the second metallic surface at a rate of at least 1.25 m/min. The process can align the first metallic surface, the polymeric surface, and the second metallic surface in a plane. 
     In some examples, contacting the polymeric surface of the component with the tool exerts a pressure of at least 100 bar on the polymeric surface. Contacting the first metallic surface of the component with the tool can exert a pressure of at least 300 bar on the first metallic surface, and contacting the second metallic surface of the component with the tool can exert a pressure of at least 300 bar on the second metallic surface. The method can further include closing a gap between at least the first metallic surface and the polymeric surface. The first metallic surface and the second metallic surface can include steel. 
     According to some examples, a method of treating a component for an electronic device can include contacting a surface of a metallic region of the component with a tool to plastically deform the region, the tool exerting a pressure of at least 100 bar on the surface of the metallic region and translating across the first metallic surface at a rate of at least 1.25 m/min, and modifying a cluster of first grains positioned at the region so that at least some of the first grains are disposed between at least some second grains at the region, the first grains including a first phase and the second grains including a second, different phase. The method can further include reducing an average grain size of first grains of the cluster of first grains, the first grains disposed in a region of the component below the metallic surface. The metallic surface can include steel. The first phase can include a sigma phase. The method can further include polishing the region of the metallic surface. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The disclosure will be readily understood by the following detailed description in conjunction with the accompanying drawings, wherein like reference numerals designate like structural elements, and in which: 
         FIG.  1    shows a top perspective view of an electronic device. 
         FIG.  2    shows an exploded perspective view of an electronic device. 
         FIG.  3    shows a perspective view of a component of an electronic device. 
         FIG.  4    shows a top perspective view of a perspective view of an electronic device. 
         FIG.  5    shows an exploded view of an electronic device. 
         FIG.  6    shows a front perspective view of an electronic device. 
         FIG.  7    shows an exploded view of an electronic device. 
         FIG.  8    shows a cross-sectional view of a portion of a component of an electronic device. 
         FIG.  9    shows a cross-sectional view of a portion of a component of an electronic device being subjected to a process. 
         FIG.  10    shows a cross-sectional view of a portion of a component of an electronic device being subjected to a process. 
         FIG.  11    shows a cross-sectional view of a portion of a component of an electronic device being subjected to a process. 
         FIG.  12    shows a cross-sectional view of a portion of a component of an electronic device. 
         FIG.  13    shows a cross-sectional view of a portion of a component of an electronic device. 
         FIG.  14    shows a cross-sectional view of a portion of a component of an electronic device. 
         FIG.  15 A  shows a cross-sectional transmission electron micrograph of a portion of a sample component of an electronic device. 
         FIG.  15 B  shows a cross-sectional transmission electron micrograph of a portion of the sample component of  FIG.  15 A . 
         FIG.  15 C  shows a cross-sectional transmission electron micrograph of a portion of the sample component of  FIG.  15 A . 
         FIG.  15 D  shows a cross-sectional transmission electron micrograph of a portion of the sample component of  FIG.  15 A . 
         FIG.  16 A  shows a cross-sectional transmission electron micrograph of a portion of a sample component of an electronic device. 
         FIG.  16 B  shows a cross-sectional transmission electron micrograph of a portion of the sample component of  FIG.  16 A . 
         FIG.  17    shows a perspective view of a component of an electronic device. 
         FIG.  18 A  shows a plot of yield strength as a function of radial depth for a component of an electronic device experiencing a simulated impact. 
         FIG.  18 B  shows a plot of yield strength as a function of radial depth for a component of an electronic device experiencing a simulated impact. 
         FIG.  19    shows a plot of hardness as a function of depth for components of an electronic device. 
         FIG.  20    shows a plot of potential as a function of current density for samples undergoing a corrosion resistance test. 
         FIG.  21    is an X-ray diffractogram for a component of an electronic device before and after a treatment process as described herein. 
         FIG.  22    is a process flow diagram of a method for treating a component of an electronic device. 
         FIG.  23    is a process flow diagram of a method for treating a component of an electronic device. 
         FIG.  24 A  shows a perspective view of a component of an electronic device and a cross-sectional view of a portion of the component. 
         FIG.  24 B  shows a cross-sectional view of the portion of the component after being subjected to a process. 
         FIG.  25 A  shows a perspective view of a component of an electronic device and a cross-sectional view of a portion of the component. 
         FIG.  25 B  shows a cross-sectional view of the portion of the component of  FIG.  25 A  and a schematic representation of a process. 
         FIG.  25 C  shows a cross-sectional view of the portion of the component of  FIG.  25 A  and a schematic representation of a process. 
         FIG.  25 D  shows a cross-sectional view of the portion of the component after being subjected to a process. 
         FIG.  26 A  shows a cross-sectional view of a portion of a component of an electronic device. 
         FIG.  26 B  shows a cross-sectional view of the portion of  FIG.  26 A  after being subjected to a process. 
         FIG.  26 C  shows a cross-sectional view of the portion of  FIG.  26 A  after being subjected to a process. 
         FIG.  27    shows a cross-sectional photograph of a portion of a sample component of an electronic device. 
         FIG.  28    shows graphs of porosity, pore size, and number of pores versus depth for sample components of an electronic device. 
         FIG.  29    shows a process flow diagram of a method for treating a component of an electronic device. 
         FIG.  30    shows a process flow diagram of a method for treating a component of an electronic device. 
         FIG.  31 A  shows a process flow diagram of a method for treating a component of an electronic device. 
         FIG.  31 B  shows a process flow diagram of a method for treating a component of an electronic device. 
     
    
    
     DETAILED DESCRIPTION 
     Reference will now be made in detail to representative embodiments illustrated in the accompanying drawings. It should be understood that the following descriptions are not intended to limit the embodiments to one preferred embodiment. To the contrary, it is intended to cover alternatives, modifications, and equivalents that can be included within the spirit and scope of the described embodiments, as defined by the appended claims. 
     One aspect of the present disclosure relates to a metallic component for an electronic device, such as a stainless steel housing, at least partially defining an exterior surface of the electronic device. A first region of the metallic component extending from the surface to a depth of at least 100 microns into the component can have an average grain size less than 45 nanometers and/or an average hardness greater than 3.5 gigapascals (GPa), while a second region of the component extending from the first region into the component to a depth of at least 900 microns can have an average grain size larger than 45 nanometers and/or an average hardness less than 3.5 GPa. Further, the grains of the first region can be distributed along a gradient transitioning from a first average grain size at the surface of the metallic component, to a second, larger grain size at the portion of the first region adjacent to the second region. 
     The metallic component can be formed or shaped, and even integrated with one or more additional components of the electronic device prior to being subjected to a treatment to form the above-described refined microstructure of the first region. That is, prior to being subjected to a treatment or process as described herein, the first region of the component can have a substantially similar microstructure to the second region, for example having an average grain size larger than 45 nanometers and/or an average hardness less than 3.5 GPa, for example having an average grain size of about 50 nanometers and an average hardness of about 3.2 GPa. A treatment to modify or refine the microstructure of the first region to include the refined microstructure described herein can include plastically deforming a desired portion of the surface of the metallic component to a depth of, for example, 10 microns at a rate of 1.25 m/min. The deformation can be achieved by translatably contacting a tool to the metallic surface, for example by rolling or grinding the tool against the surface. The tool can include a rounded contact portion having a diameter of, for example, less than 10 millimeters. 
     In some examples, a component being treated according to the processes described herein, and/or having a refined microstructure as described herein, can allow for the selection of a material or materials of the component to optimize certain desired properties, for example machinability or magnetic permeability, while also providing a desired level of hardness, durability, corrosion resistance, and other desired properties at desired locations or portions of the component. 
     For example, a housing made primarily of a metallic material, such as a stainless steel alloy can be relatively easily machined, low cost, and have other desired properties, such as a desired cosmetic appearance and desired magnetic properties. However, a component including such a stainless steel alloy often does not have desired levels of hardness, durability, or corrosion resistance without further treatment. On the other hand, for housings or other components requiring high strength materials and surfaces, a work-hardened bar or plate of metal material can be machined into a desired shape using a CNC machine. However, machining hardened metals, such as stainless steel, for example, involves longer cycle times, increases tool wear, and requires more energy. 
     In contrast, using the processes and methods described herein, a manufacturer can form a housing or other electronic component that exhibits high surface strength by first machining a relatively soft, annealed stainless steel bar or plate into shape, and then performing a hardening process on the shape. Machining the softer metal component using a CNC machine reduces tool wear, cycle time, and energy consumption. Then, using processes and methods described herein, the surface of the machined component can be hardened to meet durability requirements. In some examples, after such surface hardening processes are carried out, a finishing machining or polishing step can be performed, but only after the majority of machining has been performed prior to the hardening processes, thus extending the life of the machining tools, reducing power consumption, and reducing cycle times for higher manufacturing throughput. 
     Similarly, the manufacturer can start with a MIM stainless steel bar or plate, which is also soft relative to work hardened metals, and then machine the component prior to any surface hardening processes that are carried out as described herein. Such hardening processes, in addition to increasing strength and durability of the component, can reduce the porosity of portions of the MIM component, including portions at or near the surface. This reduced porosity can result in an enhanced aesthetic appearance of the component, as well as provide other advantageous material properties, as discussed in more detail below. 
     Further, a mismatch in hardness between layers formed over the surface of the component, such as a layer deposited by a physical vapor deposition (PVD) process and the component itself, can result in relatively high levels of interfacial stress between the surface and the layer. This interfacial stress can lead to undesirable layer delamination, for example, if the component experiences high levels of stress, such as during a drop event. 
     In contrast, a component having been subjected to a treatment, as described herein, to refine the grain structure and/or including a refined microstructure can have certain portions, for example, interior portions including the desired properties described above, while also having desired levels of surface hardness, durability, corrosion resistance, and interfacial stress with additional layers. In some examples, the entire surface or exterior of a component can be treated and/or have a refined microstructure, as described herein. In some examples, however, only select or desired portions of a component, such as portions of the component that may experience high stress or impacts, for example, the corner portions of a housing, can be treated and/or have a refined microstructure, as described herein. 
     A metallic component including a portion or portions having a refined microstructure with a first region adjacent to a surface having a smaller average grain size than a second region extending into the component from the first region can include a relatively high surface hardness or durability, as compared to an untreated portion of the component. The untreated portion can, for example, partially define an interior volume of the electronic device and can retain the properties of an untreated material, such as having a higher level of machinability than the first region, and having a desired level of magnetic permeability. 
     Additionally, the material properties of the first region including a smaller average grain size relative to the second region or untreated portions of the component, and/or a gradient distribution of grain sizes, can allow for reduced levels of interfacial stress with a layer formed over the surface of the first region. In situations where a layer, such as a ceramic layer deposited by a PVD process, is formed over the surface of a metallic component, the mismatch in hardness between the material of the PVD layer and the metallic component can result in extremely high interfacial stresses during high stress events, such as impacts. These high stresses can result in cracking of the PVD layer or delamination of the layer from the metallic component. 
     In contrast, a region having been subjected to a treatment and/or including a refined microstructure, as described herein, can have a higher hardness than untreated portions or regions of the metallic component. Accordingly, any hardness mismatch between the surface of the metallic component and the over layer can be reduced, and the interfacial stress can thus also be reduced. The reduced interfacial stresses experienced during loading, such as during an impact, can prevent or inhibit the formation of cracks and/or delamination of the layer from the metallic component. 
     A first region of a component having the refined microstructure described herein, for example including a smaller average grain size than a second region extending into the component from the first region, can be formed by any of the treatments or processes described herein, for example, via plastically deforming a portion of the surface to a desired depth by translatably contacting a tool to the surface. In some examples, the tool can have any desired geometry. In some examples, the tool can have a rounded contact portion, such as a spherical contact portion or a cylindrical contact portion. In some examples, the contact portion of the tool can be flat, concave, or can have a shape corresponding to a shape of the surface to be treated. That is, in some examples, the tool can have a contact portion matching a portion of a profile of the surface of the component being treated. 
     As compared with other techniques for affecting the grain sizes and/or microstructure of a metallic component, the treatments and processes described herein do not require the addition of thermal energy or heat to the component during processing. As such, a metallic component can be subjected to treatment after having been partially or fully integrated with one or more other components, without having to take precautions or additional process steps to prevent undesired amounts of thermal energy from being imparted to the other components. For example, a metallic component can be integrated with one or more plastic or polymer components, and can be subjected to a surface treatment or burnishing, as described herein, without melting, deforming, or otherwise affecting the plastic or polymer components. 
     Similarly, the processes described herein can be used to treat a desired portion of a metallic component, without substantially deforming the overall shape or geometry of the component. As such, the metallic component can be substantially preformed or shaped prior to the surface treatments described herein, and can avoid the need for subsequent additional shaping or forming. In contrast, other treatments or techniques that can result in a refined grain structure, such as forging and cold working, can result in undesirable levels of component deformation and can require reforming or reworking subsequent to treatment, thereby increasing the cost and processing time. 
     The processes and treatments described herein can be relatively inexpensive, and can require minimal or reduced processing time compared to traditional techniques for affecting material hardness or grain structure. The same tool used to perform such processes can be used to treat multiple components, for example, in sequential treatment operations, without the need to repair or replace the tool. Additionally, as described herein, the duration of the treatment can be relatively short and can be carried out on the component at any desired time during integration or assembly of the component into the electronic device, thereby preventing significant increases in production time or cost. 
     Additionally, the surface treatments described herein can result in a region of refined grains, that is a first region having a smaller average grain size than a second region extending into the component therefrom, that can be significantly larger or deeper than can be achieved with traditional techniques for affecting a component&#39;s grain structure. Traditional mechanical techniques for affecting the grains of a metallic material, such as shot peening, can generally only affect grains up to about 20 microns below the surface being treated. Accordingly, subsequent processing of the component, for example polishing to achieve a desired cosmetic appearance, can result in the removal of the entire affected region, thereby obviating any benefits of treatment. In contrast, the treatments and processes described herein can affect and/or refine the microstructure of a first region that can extend from the surface to a depth of at least 100 microns into the component, and in some examples, up to 800 microns into the component. The depth of the region allows for removal of significant portions of material, for example up to 50 microns during a polishing process, without removing the region having a desired microstructure. 
     In some examples, the surface treatment processes described herein can additionally or alternatively affect the structure, including the microstructure, of components in various other beneficial ways. For example, a surface treatment process as described herein can align various surfaces of a component to provide a pleasing aesthetic and tactile experience. These surfaces can even include multiple different materials, such as a metallic material and a polymeric material. In some examples, a surface treatment process can reduce or eliminate one or more gaps between various portions of a component, as described herein. In some examples, surface treatment processes described herein can modify clusters of grains of an intermetallic sigma phase. Such clusters can complicate polishing or other processes carried out on metallic components, and thus, the surface treatments described herein can reduce the size of clusters of these grains, or even reduce the size of the grains themselves. In some examples, the surface treatments described herein can reduce the porosity, number of pores, and/or average pore size of a component formed by a powder metallurgy process, such as a metal injection molding (MIM) process. 
     These and other embodiments are discussed below with reference to  FIGS.  1 - 31 B . However, those skilled in the art will readily appreciate that the detailed description given herein with respect to these Figures is for explanatory purposes only, and should not be construed as limiting. 
       FIG.  1    illustrates a perspective view of an example of an electronic device  100 . The electronic device  100  shown in  FIG.  1    is a mobile wireless communication device, such as a smartphone. The smartphone of  FIG.  1    is merely one representative example of a device that can be used in conjunction with the systems and methods disclosed herein. Electronic device  100  can correspond to any form of wearable electronic device, a portable media player, a media storage device, a portable digital assistant (“PDA”), a tablet computer, a computer, a mobile communication device, a GPS unit, a remote-control device, or any other electronic device. The electronic device  100  can be referred to as an electronic device, or a consumer device. 
     The electronic device  100  can have a housing that includes a frame or a band  102  that defines an outer perimeter and a portion of the exterior surface of the electronic device  100 . The band  102 , or portions thereof, can be joined to one or more other components of the device, as described herein. In some examples, the band  102  can include several sidewall components, such as a first sidewall component  104 , a second sidewall component  106 , a third sidewall component  108  (opposite the first sidewall component  104 ), and a fourth sidewall component (not shown in  FIG.  1   ). The aforementioned sidewall components can be joined, for example, at multiple locations, to one or more other components of the device, as described herein. The exterior surface or surfaces defined by the housing, including the surfaces of the band  102  can be treated according to the processes described herein, for example, to form a region having a smaller average grain size than the bulk material of the housing or component. In some examples, the band  102  can include a surface coating or surface finish, as described herein, such as a surface coating deposited by a physical vapor deposition process. 
     In some instances, some of the sidewall components form part of an antenna assembly (not shown in  FIG.  1   ). As a result, a non-metal material or materials can separate the sidewall components of the band  102  from each other, in order to electrically isolate the sidewall components. For example, a first separating material  112  separates the first sidewall component  104  from the second sidewall component  106 , and a second separating material  114  separates the second sidewall component  106  from the third sidewall component  108 . The aforementioned materials can include an electrically inert or insulating material(s), such as plastics and/or resin, as non-limiting examples. Further, as described herein, one or more of the sidewall components can be electrically connected to internal components of the electronic device, such as a support plate, as described herein. In some examples, these electrical connections can be achieved by joining a sidewall component to an internal component, for example, as part of the antenna assembly. 
     The electronic device  100  can further include a display assembly  116  (shown as a dotted line) that is covered by a protective cover  118 . The display assembly  116  can include multiple layers (discussed below), with each layer providing a unique function. The display assembly  116  can be partially covered by a border  120  or a frame that extends along an outer edge of the protective cover  118  and partially covers an outer edge of the display assembly  116 . The border  120  can be positioned to hide or obscure any electrical and/or mechanical connections between the layers of the display assembly  116  and flexible circuit connectors. Also, the border  120  can include a uniform thickness. For example, the border  120  can include a thickness that generally does not change in the X- and Y-dimensions. 
     Also, as shown in  FIG.  1   , the display assembly  116  can include a notch  122 , representing an absence of the display assembly  116 . The notch  122  can allow for a vision system that provides the electronic device  100  with information for object recognition, such as facial recognition. In this regard, the electronic device  100  can include a masking layer with openings (shown as dotted lines) designed to hide or obscure the vision system, while the openings allow the vision system to provide object recognition information. The protective cover  118  can be formed from a transparent material, such as glass, plastic, sapphire, or the like. In this regard, the protective cover  118  can be referred to as a transparent cover, a transparent protective cover, or a cover glass (even though the protective cover  118  sometimes does not include glass material). As shown in  FIG.  1   , the protective cover  118  includes an opening  124 , which can represent a single opening of the protective cover  118 . The opening  124  can allow for transmission of acoustical energy (in the form of audible sound) into the electronic device  100 , which can be received by a microphone (not shown in  FIG.  1   ) of the electronic device  100 . The opening  124  can also, or alternatively, allow for transmission of acoustical energy (in the form of audible sound) out of the electronic device  100 , which can be generated by an audio module (not shown in  FIG.  1   ) of the electronic device  100 . 
     The electronic device  100  can further include a port  126  designed to receive a connector of a cable assembly. The port  126  allows the electronic device  100  to communicate data (send and receive), and also allows the electronic device  100  to receive electrical energy to charge a battery assembly. Accordingly, the port  126  can include terminals that electrically couple to the connector. 
     The electronic device  100  can also include several additional openings. For example, the electronic device  100  can include openings  128  that allow an additional audio module (not shown in  FIG.  1   ) of the electronic device to emit acoustical energy out of the electronic device  100 . The electronic device  100  can further include openings  132  that allow an additional microphone of the electronic device to receive acoustical energy. Furthermore, the electronic device  100  can include a first fastener  134  and a second fastener  136  designed to securely engage with a rail that is coupled to the protective cover  118 . In this regard, the first fastener  134  and the second fastener  136  are designed to couple the protective cover  118  with the band  102 . 
     The electronic device  100  can include several control inputs designed to facilitate transmission of a command to the electronic device  100 . For example, the electronic device  100  can include a first control input  142  and a second control input  144 . The aforementioned control inputs can be used to adjust the visual information presented on the display assembly  116 , or the volume of acoustical energy output by an audio module, as non-limiting examples. The controls can include one of a switch or a button designed to generate a command or a signal that is received by a processor. The control inputs can at least partially extend through openings in the sidewall components. For example, the second sidewall component  106  can include an opening  146  that receives the first control input  142 . Further details regarding the features and structure of an electronic device are provided below, with reference to  FIG.  2   . 
       FIG.  2    illustrates an exploded view of an electronic device  200 . The electronic device  200  shown in  FIG.  2    is a smartphone, but is merely one representative example of a device that can include or be used with the systems and methods described herein. As described with respect to electronic device  100 , electronic device  200  can correspond to any form of wearable electronic device, a portable media player, a media storage device, a portable digital assistant (“PDA”), a tablet computer, a computer, a mobile communication device, a GPS unit, a remote-control device, and other similar electronic devices. In some examples, the electronic device  200  can include some or all of the features described herein with respect to electronic device  100 . 
     The electronic device can have a housing that includes a band  202  that at least partially defines an exterior portion, such as an outer perimeter, of the electronic device. As with the band  102  described above in  FIG.  1   , the band  202  can include several sidewall components, such as a first sidewall component  204 , a second sidewall component  206 , a third sidewall component  208  (opposite the first sidewall component  204 ), and a fourth sidewall component  210 . The band  202  can also include a non-metal material or materials that separate and/or join the sidewall components of the band  202  with each other, as described herein. For example, separating material  214  can separate and/or join the second sidewall component  206  with the third sidewall component  208 . In some other instances, however, the band  202  may not include any separating material  214  and can be a solid and substantially unitary metallic component such that the sidewall components  204 ,  206 ,  208 , and  210  are a single body. 
     The housing, including the band  202 , can include one or more features to receive or couple to other components of the device  200 . For example, the band  202  can include any number of features such as apertures, cavities, indentations, and other mating features to receive and/or attach to one or more components of the device  200 . The electronic device  200  can include internal components such as processors, memory, circuit boards, batteries, and sensors. Such components can be disposed within an internal volume defined, at least partially, by the band  202 , and can be affixed to the band  202 , via internal surfaces, attachment features, threaded connectors, studs, posts, and/or other fixing features, that are formed into, defined by, or otherwise part of the band  202 . For example, attachment feature  222  can be formed in the band  202 . In some examples, the attachment feature  222  can be formed by a subtractive process, such as machining. Accordingly, the portion of the band  202  where the attachment feature  222  is to be formed may not be subjected to a treatment or include a refined microstructure as described herein, to allow for relative ease of formation of the feature  222 . 
     The device  200  can include internal components, such as a system in package (SiP)  226 , including one or more integrated circuits such as a processors, sensors, and memory. The device  200  can also include a battery  224  housed in the internal volume of the device  200 . The device  200  can also include one or more sensors, such as optical or other sensors, that can sense or otherwise detect information regarding the environment exterior to the internal volume of the device  200 . Additional components, such as a haptic engine, can also be included in the device  200 . The electronic device  200  can also include a display assembly  216 , similar to display assembly  116 , described herein. In some examples, the display assembly  216  can be received by and/or be attached to the band  202  by one or more attachment features. In some examples, one or more of these internal components can be mounted to a circuit board  220 . The electronic device  200  can further include a support plate  230 , also referred to as a back plate or chassis, that can provide structural support for the electronic device  200 . The support plate  230  can include a rigid material, such as a metal or metals. 
     An exterior surface of the electronic device  200  can further be defined by a back cover  240  that can be coupled to one or more other components of the device  200 . In this regard, the back cover  240  can combine with the band  202  to form an enclosure or housing of the electronic device  200  with the enclosure or housing (including band  202  and back cover  240 ) at least partially defining an internal volume and an exterior surface. The back cover  240  can include a transparent material such as glass, plastic, sapphire, or the like. In some examples, the back cover  240  can be a conductive transparent material, such as indium titanium oxide or a conductive silica. The exterior surface or surfaces defined by the housing, including the surfaces of the band  202  and/or the back cover  240 , can be subjected to a treatment as described herein and can include a region or regions having the refined microstructure and properties described herein. As such, the band  202  and the back cover  240  can be formed from any number of desired materials, such as metallic materials. In some examples, other components, such as internal components of the electronic device  200 , for example a support plate  230 , can also be subjected to a treatment as described herein and can include a region having a refined microstructure as described herein. Further details regarding coating a component of an electronic device are provided below with reference to  FIG.  3   . 
       FIG.  3    illustrates a component  302  of an electronic device. The electronic device can be a smartphone, and can include any of the features of devices  100  and  200 , as described with respect to  FIGS.  1  and  2   . The component  302  can be a band  302  of a smartphone, similar to band  102  and band  202  described with respect to  FIGS.  1  and  2   . As with bands  102  and  202 , the band  302  can include several sidewall components,  304 ,  306 ,  308 , and  310 , or in some examples, can be a substantially unitary body. In embodiments where the band  302  includes sidewall components  304 ,  306 ,  308 ,  310 , they can be joined together by a material  314 . The material  314  can be any material as desired, for example, a non-conductive material such as a non-conductive polymer. In some examples, as described herein, the components  304 ,  306 ,  308 ,  310  can be integrated with or joined by the material  314  prior to being subjected to a treatment, as described herein, without the treatment degrading or undesirably affecting the material  314 . One or more components  304 ,  306 ,  308 ,  310  can also include features formed therein, for example, an aperture  326  formed in component  308 . 
     The band  302  can include or be formed from a metallic material, such as aluminum, titanium, or stainless steel. For example, the sidewall components  304 ,  306 ,  308 ,  310  forming the band  302  can include a stainless steel alloy, for example a 316 L stainless steel alloy. The band  302  and the sidewall components  304 ,  306 ,  308 ,  310  can also include a surface coating, such as a coating deposited by a physical vapor deposition process, as described herein. In some examples, the band can include one or more regions, such as regions that define an exterior surface of the electronic device, that include a refined microstructure, as described herein. In some embodiments, an entire surface of the band  302  can have a refined microstructure, as described herein, for example, having a grain size distribution including smaller grains at the surface of the band and transitioning along a gradient to larger grains near to the interior of the band material. 
     Accordingly, an electronic device including the band  302  can have a portion or portion including the refined microstructure described herein, for example, including a first region extending from the surface to a depth and having a first average grain size, and a second region extending from the first region further into the portion and having a second, larger average grain size. In some examples, the first region can include a grain size distribution transitioning from an average grain size at the surface to a larger average grain size at a portion of the first region adjacent to the second region. Further, in some examples, multiple components or portions of components can include a refined microstructure, as described herein, formed according to the processes described herein. 
     Any number or variety of electronic device components can include a component that has been subjected to a surface treatment, as described herein. The surface treatment or treatments can refine or modify a microstructure of some or all of the component, can densify or reduce the porosity of some or all of the component, and/or can align or reduce gaps between portions of the component. One or more of these surface treatments can include plastically deforming the surface to a desired depth, and/or applying a desired amount of pressure to the surface, as described herein. The component can then be treated, for example, by polishing or forming a surface layer. Various examples of components having been subjected to surface treatments as described herein, surface coatings, and processes for forming the same are described below with reference to  FIGS.  4  and  5   . 
       FIG.  4    shows another electronic device  400 . The electronic device shown in  FIG.  4    is a laptop computer. As with electronic devices  100  and  200  discussed herein, the laptop computer  400  of  FIG.  4    is merely one representative example of a device that can be used in conjunction with the components and methods disclosed herein. Electronic device  400  can correspond to any form of electronic device, such as a wearable electronic device, a portable media player, a media storage device, a portable digital assistant (“PDA”), a tablet computer, a computer, a mobile communication device, a GPS unit, or a remote-control device. The electronic device  400  can be referred to as an electronic device, or a consumer device. The electronic device  400  can have an exterior housing  402 , a display  404 , and input components  406 ,  408 . Further details of the electronic device  400  are provided below with reference to  FIG.  5   . 
     Referring now to  FIG.  5   , the electronic device  400  can include a housing  402  that at least partially defines an exterior surface of the device  400 . The device  400  can also include internal components, such as processors  410 , memory, circuit boards, batteries  412 , sensors  414 , speakers, and other internal computing components. Such components can be disposed within an internal volume defined at least partially by the housing  402 , and can be affixed to the housing  402  via internal surfaces, attachment features, threaded connectors, studs, posts, and/or other features, that are formed into, extending into the body from, or otherwise part of the housing  402 . 
     As with the housings of electronic devices  100  and  200 , the housing  402  can be formed from substantially any metallic material, for example aluminum, steel, titanium, or other metals described herein. In some embodiments, the housing  402  can further include a surface layer or coating formed over the metallic material, such as a layer deposited by a physical vapor deposition process. Thus, in some examples, the housing  402  can have a desired refined microstructure, and a desired hardness or hardness profile, as described herein. Additionally, other components of the electronic device  400  can include a refined microstructure, as described herein. In some examples, substantially any portion or entire exterior surface of a component, such as the housing  402 , can have a refined microstructure, as described herein. Accordingly, the portion on which a treatment is carried out and which includes a refined microstructure as described herein can be any three-dimensional surface. That is, the portion including the refined microstructure described herein is not required to be planar and can include curves, protrusions, folds, corners, bends, or any other three-dimensional features. In some examples, a three-dimensional surface can be a surface that has an amount of curvature or is non-planer in two or more orientations. 
     Any number or variety of electronic device components can include a component that has been subjected to a surface treatment, as described herein. The surface treatment or treatments can refine or modify a microstructure of some or all of the component, can densify or reduce the porosity of some or all of the component, and/or can align or reduce gaps between portions of the component. One or more of these surface treatments can include plastically deforming the surface to a desired depth, and/or applying a desired amount of pressure to the surface, as described herein. The component can then be treated, for example, by polishing or forming a surface layer. Various examples of components having been subjected to surface treatments as described herein, surface coatings, and processes for forming the same are described below with reference to  FIGS.  6  and  7   . 
       FIG.  6    shows another embodiment of an electronic device  500 . The electronic device shown in  FIG.  6    is a watch, such as a smartwatch. The smartwatch  500  of  FIG.  6    is merely one representative example of a device that can be used in conjunction with the components and methods disclosed herein. As described with respect to electronic devices  100 ,  200 ,  400 , electronic device  500  can correspond to any form of wearable electronic device, a portable media player, a media storage device, a portable digital assistant (“PDA”), a tablet computer, a computer, a mobile communication device, a GPS unit, a remote control device, and other devices. The electronic device  500  can be referred to as an electronic device, or a consumer device. Further details of the watch  500  are provided below with reference to  FIG.  7   . 
     Referring now to both  FIGS.  6  and  7   , the electronic device  500  can include a housing  502 , and a cover  516  attached to the housing. The housing  502  can substantially define at least a portion of an exterior surface of the device  500 . The cover  516  can include glass, plastic, or any other substantially transparent material, component, or assembly. The cover  516  can cover or otherwise overlay a display, a camera, a touch sensitive surface, such as a touchscreen, or other component of the device  500 . The cover  516  can define a front exterior surface of the device  500 . A back cover  530  can also be attached to the housing  502 , for example opposite the cover  516 . The back cover  530  can include ceramic, plastic, metal, or combinations thereof. In some examples, the back cover  530  can include an electromagnetically transparent portion  532 . The electromagnetically transparent portion  532  can be transparent to any wavelength of electromagnetic radiation, such as visual light, infrared light, radio waves, or combinations thereof. Together, the housing  502 , cover  516 , and back cover  530  can substantially define an interior volume and exterior surface of the device  500 . 
     As with the housing  100 ,  200 , and  400 , the housing  502  can be formed from a metallic material and can include a portion or portions having the refined microstructure described herein. The portions, for example the portions of the housing  502  at least partially defining the exterior surface of the device  500 , can include a first region extending from the surface to a desired depth having a first average grain size, and a second region extending from the first region into the housing  502  having a second, larger average grain size. The grains of the first region can have sizes distributed along a gradient, transitioning from smaller grains at the surface to larger grains at the portion of the first region adjacent to the second region. In some examples, the housing  502  can also include a surface layer formed by a physical vapor deposition process. 
     The housing  502  can be a substantially continuous or unitary component and can include one or more openings  504 ,  506  to receive components of the electronic device  500  and/or provide access to an internal portion of the electronic device  500 . Additionally, other components of the electronic device  500 , can be formed from or can include a metallic material including a portion or portions having the refined microstructure described herein. In some embodiments, the device  500  can include input components such as one or more buttons  542  and/or a crown  544  that can be formed from a metallic material including a portion or portions having the refined microstructure described herein. The metallic material including a portion or portions having the refined microstructure described herein can provide for strong and durable input components  542 ,  544  as discussed herein. 
     The electronic device  500  can further include a strap  550 , or other component designed to attach the device  500  to a user, or to provide wearable functionality. In some examples, the strap  550  can be a flexible material that can comfortably allow the device  500  to be retained on a user&#39;s body at a desired location. Further, the housing  502  can include a feature or features that can provide attachment locations for the strap  550 . In some embodiments, the strap  550  can be retained on the housing  502  by any desired techniques. For example, the strap  550  can include any combination of magnets that are attracted with magnets disposed within the housing  502 , or retention components that mechanically retain the strap  550  against the housing  502 . 
     The device  500  can also include internal components, such as a haptic engine  524 , a battery  522 , and a system in package (SiP), including one or more integrated circuits  526 , such as processors, sensors, and memory. The SiP can also include a package. All or a portion of one or more internal components, for example the package of the SiP, can be formed from, or can include, a metallic material including a portion or portions having the refined microstructure described herein. 
     The internal components, such as one or more of components  522 ,  524 ,  526  can be disposed within an internal volume defined at least partially by the housing  502 , and can be affixed to the housing  502  via internal surfaces, attachment features, threaded connectors, studs, posts, or other features, that are formed into, defined by, or otherwise part of the housing  502  and/or the cover  516  or back cover  530 . In some embodiments, the attachment features can be formed relatively easily on interior surfaces of the housing  502 , for example, by machining, because those portions of the housing have not been subjected to a surface treatment, as described herein. 
     The housing  502  formed from a metallic material including a portion or portions having the refined microstructure described herein can be conformable to interior dimensional requirements, as defined by the internal components  522 ,  524 ,  526 . For example, the structure of the housing  502  can be defined or limited exclusively or primarily by the internal components the housing  502  is designed to accommodate. That is, because a housing  502  formed from a metallic material including a portion or portions having the refined microstructure described herein can be extremely strong, hard, and durable, the housing  502  can be shaped to house the interior components  522 ,  524 ,  526  in a dimensionally efficient manner without being constrained by factors other than the dimensions of the components, such as the need for additional structural elements. 
     Any number or variety of electronic device components can include a component that has been subjected to a surface treatment, as described herein. The surface treatment or treatments can refine or modify a microstructure of some or all of the component, can densify or reduce the porosity of some or all of the component, and/or can align or reduce gaps between portions of the component. One or more of these surface treatments can include plastically deforming the surface to a desired depth, and/or applying a desired amount of pressure to the surface as described herein. The component can then be treated, for example, by polishing or forming a surface layer. Various examples of components having been subjected to surface treatments as described herein, surface coatings, and processes for forming the same are described below with reference to  FIGS.  8 - 11   . 
       FIG.  8    illustrates a cross-sectional view of a portion of a component  600  of an electronic device that has not been subjected to a surface treatment, as described herein. In some embodiments, the component  600  can be a housing of an electronic device and can include some or all of the features of the housings  100 ,  200 ,  400  described herein. The component  600  can include or be formed from a metallic material, for example aluminum, steel, titanium, other metals, or alloys thereof. Thus, in some examples, the component  600  can include crystalline grains  602 ,  604 . Each crystalline grain  602 ,  604  can have a grain size. As used herein, the term grain size refers to the largest diameter or largest linear dimension of an individual crystalline grain. In some instances, such as for grains that may not be substantially spherical, or that may be highly elongated in one or two dimensions, the grain size can refer to an average of any number of diameters of the crystalline grain. Further, a region or regions of the component  600 , for example the region illustrated in  FIG.  8   , can have an average grain size. As used herein, the term average grain size refers to the sum total of the grain size of each grain within the region divided by the total number of grains. 
     As can be seen, an untreated component  600  including or formed from a metallic material can have grains  602  near the external surface  610  that are substantially the same size as grains  604  in the interior region of the component  600 . In some examples, the average grain size of the component  600 , including grains  602  and  604 , can be greater than 45 nanometers, greater than 46 nanometers, greater than 47 nanometers, greater than 48 nanometers, greater than 49 nanometers, greater than 50 nanometers, greater than 60 nanometers, greater than 75 nanometers, or even 100 nanometers or greater. Accordingly, the mechanical properties of the metallic material forming the component  600  can be substantially similar at the surface  610  and near the interior, for example, adjacent to the grain  604 . As described herein, if the metallic material of the component  600  is selected to provide for ease of machinability, the surface  610  may not have a desired level of hardness or durability. Conversely, if the metallic material of the component  600  is selected to provide a desired level of hardness, it will likely be difficult, expensive, and/or time consuming to machine features into the component  600 . The surface treatment described herein, however, can allow for a metallic material that has a desired level of machinability, while also providing surface  610  with a desired level of hardness. The component  600  can include any desired shape or form, and can be subjected to a surface treatment, as described herein and as illustrated in  FIGS.  9 - 11   . 
       FIG.  9    shows a cross-sectional view of a portion of a component  700  of an electronic device being subjected to a surface treatment process, also referred to as a burnishing process. In some examples, the component  700  can be substantially similar to the untreated component  600  described with respect to  FIG.  8   . In some examples, one or more portions of the component  700 , for examples portions that are not shown, can be subjected to a similar or identical surface treatment or burnish, as will be described. As such, prior to treatment, the portion of the component  700  depicted in  FIG.  9    can have a substantially uniform or regular distribution of grain sizes throughout, again, similar to the grain structure illustrated with respect to component  600  illustrated in  FIG.  8   . 
     During a surface treatment process, or burnishing process the contact portion  710  of a tool is brought into contact with a surface  702  of the component  700  at a location where the formation of a first region including refined grains is desired. The contact portion  710  contacts the component  700  at the surface  702  and exerts sufficient force against the component  702  to plastically deform the surface  702  to a desired depth, as illustrated. As used herein, the desired deformation depth can refer to the deformation that occurs locally under the contact portion  710 . In some examples, this deformation can cause a protrusion or bulging of the surface  702  adjacent to the contact portion  710 , although the contact portion  710  can subsequently contact and deform these areas of the surface  702 , as shown in  FIGS.  10  and  11   . 
     The contact portion  710  of the tool can plastically deform the surface  702  to a depth of at least 10 microns. In some examples, the contact portion  710  of the tool can plastically deform the surface  702  to a depth of at least 12 microns, at least 15 microns, at least 20 microns, at least 25 microns, at least 30 microns, at least 40 microns, or at least 50 microns or more. Further, in some examples, the depth to which the contact portion  710  plastically deformed the surface  702  can be controllably varied at various desired locations. Additionally, the force required to deform the surface  702  to a desired depth may vary at different locations on the surface  702 , for example, due to the component geometry, material defects, differences in composition, and other factors. In some examples, the contact portion  710  of the cool can exert a pressure on the surface  702  of the component  700  of between about 1 bar and about 1000 bar, between about 10 bar and about 1000 bar, between about 50 bar and about 500 bar, or between about 100 bar and about 300 bar. 
     In some examples and as illustrated, the contact portion  710  of the tool can have a substantially rounded shape or profile, such as a spherical, ovoid, or other rounded shape. In some examples, the contact portion  710  can have a cylindrical shape. In some examples, the contact portion  710  can have any shape that can achieve or produce the desired depth of plastic deformation of the surface  702 . In some examples, the contact portion  710  can have a shape corresponding to a shape of the surface  702  to be treated. That is, in some examples, the tool can have a contact portion  710  having a profile that matches the surface  702  of the component being treated. In some examples, such as where the contact portion  710  has a spherical or rounded shape, the diameter or width of the contact portion  710  can be between 1 millimeter and 50 millimeters. In some embodiments, the contact portion  710  can be substantially spherical and can have a diameter of 8 millimeters or 10 millimeters. 
     The area of the surface  702  that directly contacts the contact portion  710  can be referred to as the contact patch or contact area of the tool. The size of this contact area can vary depending on the size of the contact portion  710  and the depth to which the surface  702  is deformed. In some instances, the contact area can be significantly smaller than the diameter or size of the contact portion  710 . For example, the contact area can be less than 500 square microns. In some examples, the contact area can be less than 400 square microns, less than 300 square microns, less than 250 square microns, less than 200 square microns, less than 150 square microns, or less than 100 square microns. As used herein, the term contact patch or contact area can refer to the area of the surface  702  directly engaged or contacted by the contact portion  710  when the tool is stationary with respect to the surface  702 . Thus, while the contact portion  710  can be translated across the surface  702  and can come into contact with large areas thereof, for example, as illustrated in  FIGS.  10  and  11   , the contact area is nevertheless defined as the area instantaneously contacted by the contact portion  710  at any given time and location. 
     The contact portion  710  can, in some embodiments, be integrated or attached to a tool that is compatible with a CNC or other machining apparatus or tool. Accordingly, in some examples, the surface treatment described herein can be integrated into existing process flows for component manufacture or device assembly. Thus, a desired portion of the component  700  can be subjected to a surface treatment without significantly increasing production costs or processing times. Further, the contact portion  710  can be integrated with or used by hardware or apparatuses that can already be used during component  700  manufacture or assembly, again preventing large increases in cost or processing time. 
     The plastic deformation of the surface  702  caused by the contact portion  710  can produce or result in the formation of a region  704  extending from the surface  702  to a desired depth into the component  700 . The crystalline grains of this region  704  can be affected by the contact portion  710  and can be reduced in size such that the area  704  has a smaller average grain size than the adjacent regions of the component  700 . Although referred to herein as being reduced in size, without being bound by any one theory, the reducing in average grain size can be due to one or more factors, such as the division of single grains into multiple grains, the formation of new, smaller grains, and other similar grain defining factors. 
     The region  704  having a reduced average grain size, and/or an average grain size smaller than an adjacent region or regions, also referred to as a first region, can extend a desired depth into the component from the surface  702 . In some examples, the region  704  can extend to a depth of at least 100 microns, for example to a depth of 300 microns. In some examples, the region  704  can extend to a depth of at least 150 microns, at least 200 microns, at least 250 microns, at least 300 microns, at least 400 microns, at least 500 microns, at least 600 microns, at least 700 microns, at least 800 microns, at least 900 microns, or even up to 1 mm into the component from the surface  702 . 
     A second region, for example, including unaffected or unrefined grains having an average grain size greater than 45 or 50 nanometers, can be considered to extend from the first region further into the component  700 . Accordingly, the second region can extend from the first region  704  through the entire remaining thickness of the component  700  underlying the first region. In some examples, the second region can extend from the first region  704  to a depth at least 100 microns further into the component  700 , for example to a depth of 300 microns further into the component  700  than the first region  704 . In some examples, the second region can extend to a depth of at least 150 microns further than the first region  704 , at least 200 microns, at least 250 microns, at least 300 microns, at least 400 microns, at least 500 microns, at least 600 microns, at least 700 microns, at least 800 microns, at least 900 microns, or 1 mm or deeper than the first region  704 . Further, in some examples, the thickness of the component  700  can be less than the depth to which the region  704  extends from the surface  702 . That is, in some examples, the region  704  can extend substantially through an entire width or depth of a component  700 . While the interaction between the tool  710  and surface  702  of the component  700  is shown at one location in  FIG.  9   , in some examples the tool can be translated across the surface  702  of the component  700  to refine the grains over an extended portion  704  of the component  700 . 
     In some examples, the region  704  can have an average grain size less than 50 nanometers, for example less than 49 nanometers, less than 48 nanometers, less than 47 nanometers, less than 46 nanometers, less than 45 nanometers, less than 44 nanometers, less than 43 nanometers, less than 42 nanometers, less than 41 nanometers, less than 40 nanometers, less than 35 nanometers, or less than 30 nanometers. 
       FIG.  10    shows a cross-sectional view of a portion of a component  700  of an electronic device being subjected to a surface treatment process, as described herein. As with the process shown in  FIG.  9   , in some examples, the contact portion  710  of a tool can contact the surface  702  of a component  700  and plastically deform the surface  702  to a desired depth, thereby forming a region  704  having a smaller average grain size than adjacent and/or untreated regions of the component  700 . Further, as shown in  FIG.  10   , the contact portion  710  can be slid, ground, or otherwise translated against the surface  702 , such that it translatably contacts the surface  702 , indicated in  FIG.  10    with an arrow. In some examples, the contact portion  710  can move at a rate of between about 0.01 meters/minute (m/min) and about 10 m/min. In some examples, the contact portion  710  can move at a rate of between about 0.1 m/min and about 5 m/min, between about 0.5 m/min and about 2.5 m/min, or between about 1 m/min and about 2 m/min, for example about 1.25 m/min. 
     As the contact portion  710  translates across the surface  702  while in contact therewith, the region  704  is formed below the contact portion  710  to a desired depth. Accordingly, the region  704  can be substantially any desired size or area, and in some examples, can be disposed under substantially any amount of surface  702  of the component  700 . Further, the force exerted by the tool on the component  700  can provide additional benefits beyond the formation of the region  704 . For example, the force exerted by the tool can straighten or align all or a portion of the component  700  and can ensure that the surface  702  is substantially flat or planar. 
       FIG.  11    shows a cross-sectional view of a portion of a component  700  of an electronic device being subjected to a surface treatment process, as described herein. Similar to the process illustrated in  FIG.  10   , the contact portion  710  of the tool can be translated across the surface  702  to form a desired region  704 . Whereas the contact portion  710  was slid or ground over the surface  702  in  FIG.  10   , the process illustrated in  FIG.  11    can include rolling the contact portion  710  over the surface  702  to form the region  704 . Further, the examples illustrated in  FIGS.  10  and  11    can be combined as desired. That is, in some examples, the contact portion  710  can both be slid across the surface  702  at a desired rate and rotated while in contact therewith at a desired rate. 
     Any number or variety of electronic device components can include a component that has been subjected to a surface treatment, as described herein. The surface treatment or treatments can refine or modify a microstructure of some or all of the component, can densify or reduce the porosity of some or all of the component, and/or can align or reduce gaps between portions of the component. One or more of these surface treatments can include plastically deforming the surface to a desired depth, and/or applying a desired amount of pressure to the surface as described herein. The component can then be treated, for example, by polishing or forming a surface layer. Various examples of components having been subjected to surface treatments as described herein, surface coatings, and processes for forming the same are described below with reference to  FIGS.  12 - 14   . 
       FIG.  12    illustrates a cross-section view of a portion  800  of a component of an electronic device after being subjected to a surface treatment, for example region  704  illustrated in  FIGS.  9 - 11   , and as described herein. In some examples, the component can be substantially similar and can have a substantially similar grain structure to the untreated component  600  illustrated in  FIG.  8   . The portion  800  of the component illustrated in  FIG.  12    can correspond to the treated region  704  depicted in  FIGS.  9 - 11   . Thus, the average grain size of the entire region  800  illustrated in  FIG.  12    can be less than 50 nanometers, for example less than 49 nanometers, less than 48 nanometers, less than 47 nanometers, less than 46 nanometers, less than 45 nanometers, less than 44 nanometers, less than 43 nanometers, less than 42 nanometers, less than 41 nanometers, less than 40 nanometers, less than 35 nanometers, less than 30 nanometers, or even smaller. Even though the average grain size of the entire region  800  illustrated in  FIG.  12   , for example extending from the surface  810  to a desired depth into the component, can be less than a desired size, such as 45 nanometers, the grains can be distributed along a grain size gradient with smaller grains  802  adjacent to the surface  810 , and larger grains  804  adjacent to a second region having an average grain size larger than, for example, 45 nanometers. 
     As a result of the modified microstructure and refined grains in the region  800  illustrated in  FIG.  12   , the affected portion  800  of the component can have a number of modified or desirable material properties. For example, the affected or refined portion  800  can have a significantly increased hardness relative to unaffected or untreated portions of the component. In some embodiments, the component can include or be formed from a stainless steel alloy, such as 316 L stainless steel. The hardness of 316 L stainless steel that has not been subjected to a treatment as described herein can be about 2 GPa. The region  800  including a refined microstructure, as described herein, however, can have a hardness that is greater than 3 GPA, greater than 3.5 GPa, greater than 4 GPa, 5 GPa, or even up to 6 GPa. Thus, in some embodiments, a refined microstructure region  800  of a component can have a hardness that is 1.5 times, 2 times, or even up to 3 times harder than an untreated portion of the component or material. 
     In addition to increasing the hardness of the material in the region  800 , other material properties of the region  800  can be improved relative to untreated or unaffected portions of the component, as desired. In some examples the corrosion resistance and open circuit pitting potential of the material in region  800  can be improved, relative to the untreated or unaffected portions of the component. For example, the open circuit potential, or critical crevice potential of the region  800  can be higher or more positive than the untreated or unaffected portions of the component. In some examples, the open circuit potential of the region  800  can be up to 10 millivolts (mV), 25 mV, 50 mV, 100 mV, 200 mV, 500 mV, 1V, 2V, or even 5V or more than the open circuit potential of the untreated or unaffected portions of the component in an electrolytic solution. 
     Further, the treatment to refine the grains of the component in the region  800  can achieve this result without imparting undesirable properties to the region  800  or the component. For example, some traditional techniques for refining the grains of a material, such as shot peening, can result in a rough surface. This rough surface can often demand additional processing in order to achieve a desired level of smoothness, and in some examples, such processing can even result in the removal of significant portions of the region  800 . Accordingly, in some examples, the surface  810  of the component can have a surface roughness less than 0.5 microns, less than 0.25 microns, less than 0.1 microns, or even smaller, for example about 0.08 microns. In some cases, the surface roughness of the surface  810  can be less than 0.05 microns or smaller. 
     The refined microstructure described herein can also be achieved without the formation of additional material phases that can impart undesirable properties to the component. In some examples, the untreated portions of the component can have a first magnetic permeability. Subsequent to a refining treatment, as described herein, the treated portion  800  can have a magnetic permeability that is substantially similar or identical to the untreated component. For instance, where the component includes a stainless steel alloy having a magnetic permeability of 1.05μ in its untreated or unrefined form, the treated region  800  including an average grain size less than 45 can have a magnetic permeability of 1.05μ. 
     In some instances, this can be because no magnetic phases have been formed in the material during treatment. For example, where an untreated component can include less than about 1 volume percent of a martensitic phase, the treated region  800  can similarly include less than 1 volume percent of a martensitic phase. In some examples, the region  800  can include less than 1 volume percent of a martensitic phase, less than 0.8 volume percent of a martensitic phase, less than 0.6 volume percent of a martensitic phase, less than 0.4 volume percent of a martensitic phase, less than 0.2 volume percent of a martensitic phase, or even about 0.1 volume percent of a martensitic phase. 
     The component including a refined grain structure in a region  800  can be subjected to additional subsequent treatment or processing, as described herein.  FIG.  13    shows a cross-sectional view of a portion or region  800  of a component of an electronic device having an average grain size less than 45 nanometers, for example after being treated by a surface treatment process, as described herein. In this example, an additional layer  820  of material has been deposited or formed over the surface  810 . In some embodiments, the surface  810  can have a small enough surface roughness to deposit or form the layer  820  without additional processing. In some other embodiments, however, the surface  810  can be subjected to additional treatment or processing, for example, to smooth the surface  810  prior to formation of the layer  820 . In some examples, the layer  820  can be formed by a vapor deposition process, such as a physical vapor deposition process or a chemical vapor deposition process. In some examples, the layer  820  can have any desired thickness, and can be up to 10 microns, 20 microns, 50 microns, 100 microns, 250 microns, 500 microns, or more in thickness. In some examples, the layer  820  can include a ceramic material, such as a carbide, a nitride, or a carbonitride. In some examples, the layer  820  can include titanium carbonitride, chromium carbonitride, or combinations thereof. 
       FIG.  14    shows a cross-sectional view of a portion or region  800  of a component of an electronic device having an average grain size less than 45 nanometers, for example, after being treated by a surface treatment process, as described herein. Traditional techniques for surface hardening or surface materials, such as shot peening, can only affect the material to depths of about 20 microns, whereas polishing processes can remove up to about 50 microns of material from the surface. Accordingly, such polishing can remove substantially all of the treated portion of a component, thereby obviating any benefit of the treatment. In this example, however, because the region  800  extends into the component at least about 100 microns, and in some examples up to 1 millimeter, the component can be subjected to a polishing treatment to achieve both a desired surface smoothness and a desired cosmetic appearance without obviating the benefit of the treatment. In some examples, the polishing treatment can be a mechanical polishing treatment, a chemical polishing treatment, or combinations thereof. In some examples, such polishing treatments can remove a portion of surface material  830  that can extend up to 10 microns, up to 25 microns, or even up to 50 microns into the component. Even with this surface portion  830  removed by polishing, the grains  806  now present at the surface have still been refined, and the average grain size of the region  800  can still be less than about 45 nanometers. 
     Any number or variety of electronic device components can include a component that has been subjected to a surface treatment, as described herein. The surface treatment or treatments can refine or modify a microstructure of some or all of the component, can densify or reduce the porosity of some or all of the component, and/or can align or reduce gaps between portions of the component. One or more of these surface treatments can include plastically deforming the surface to a desired depth, and/or applying a desired amount of pressure to the surface as described herein. The component can then be treated, for example, by polishing or forming a surface layer. Various examples of components having been subjected to surface treatments as described herein, surface coatings, and processes for forming the same are described below with reference to  FIGS.  15 A- 16 B . 
       FIG.  15 A  shows a cross-sectional transmission electron micrograph of a portion of a sample component  900  including a 316 L alloy of stainless steel that has been subjected to a process for forming a refined microstructure, as described herein. The process was substantially similar to the processes illustrated and described with respect to  FIGS.  9 - 11   . In this particular example, the contact portion was translated from left to right across the surface  910  of the sample  900 . The contact portion exerted a pressure on the surface  910  of the component  900  of about 100 bar and was translated at a rate of about 1.25 meters/minute. 
     As can be seen, and as described with respect to  FIG.  12   , the sample component  900  can include smaller compressed grains  902  that are adjacent to the surface  910  and relatively larger and relatively uncompressed grains  904  that are disposed below the grains  902 . The compressed grains  902  adjacent to the surface  910  can have a horizontal layered structure and can have a thickness or height as illustrated of less than about 50 nm, for example between about 10 nm and about 50 nm. The grains  902  can have a substantially planar, platelet or pancake like shape, with the length and width of the grains  902  being much larger than the thickness or height of the grains  902 . The grains  902  can extend to a depth of about 1 to 2 microns below the surface  910 . 
     Further, as can be seen, the sample component  900  can include intermediate grains  906  that can be disposed between the grains  902  and the grains  906 . These intermediate grains can have an elongated tubular structure and can extend at an angle relative to the surface  910 . That is, the elongated tubular grains  906  can be oriented with their longest dimension at an angle of less than 90 degrees and greater than 0 degrees relative to the surface  910 . 
       FIG.  15 B  shows a cross-sectional transmission electron micrograph of a portion of the sample component  900  of  FIG.  15 A . This particular transmission electron micrograph shows a close-up of the compressed grains  902  and the elongated tubular grains  906  described herein. As can be seen, the compressed grains can have a length of about 100 nm to 1000 nm, with substantially smaller thicknesses of about 10 nm to about 50 nm. The width of the grains  902 , although not shown, can be similar to or less than the length, that is about 100 nm to 1000 nm. 
       FIG.  15 C  shows a cross-sectional transmission electron micrograph of a portion of the sample component  900  of  FIG.  15 A . This particular transmission electron micrograph shows a close-up of the elongated tubular grains  906  and the relatively uncompressed grains  904 . The elongated grains  906  can be oriented at an angle of between about 30 degrees and about 60 degrees relative to the surface  910 . Further, the elongated grains  906  can have a thickness that can be substantially similar to the grains  902 . That is, the elongated grains can have a thickness of about 10 nm to about 50 nm. The elongated grains  906  can have a length of between about 1 micron to 3, 4, 5, or even more microns. 
       FIG.  15 D  shows a cross-sectional transmission electron micrograph of a portion of the sample component  900  of  FIG.  15 A . This particular transmission electron micrograph shows a close-up of the relatively uncompressed grains  904 , with the elongated grains  906  overlaying the relatively uncompressed grains  904 . The grains  904  can be larger in one or more dimensions than the grains  902 ,  906 , and can be substantially equiaxial. 
       FIG.  16 A  shows a cross-sectional transmission electron micrograph of a portion of a sample component  1000  including a 316 L alloy of stainless steel that has been subjected to a process for forming a refined microstructure, as described herein. The process was substantially similar to the processes illustrated and described with respect to  FIGS.  9 - 11   . In this particular example, the contact portion was translated from left to right across the surface  1010  of the sample  1000 . The contact portion exerted a pressure on the surface  1010  of the component  1000  of about 300 bar, and was translated at a rate of about 1.25 meters/minute. 
     As can be seen, and as described with respect to  FIGS.  12  and  15 A- 15 D , the sample component  1000  can include smaller compressed grains  1002  that are adjacent to the surface  1010 , and elongated grains and relatively larger uncompressed grains that are disposed below the grains  1002 . The compressed grains  1002  adjacent to the surface  1010  can have a horizontal layered structure and can have a thickness or height as illustrated of less than about 50 nm, for example, between about 10 nm and about 50 nm. The grains  1002  can have a substantially planar, platelet, or pancake like shape, with the length and width of the grains  1002  being much larger than the thickness or height of the grains  1002 . 
       FIG.  16 B  shows a cross-sectional transmission electron micrograph of a portion of the sample component  1000  of  FIG.  16 A . This particular example shows that because of the higher pressure of about 300 bar exerted by the contact portion of the tool during processing, the microstructure and the grains of the sample  1000  can be affected and deformed to a depth of several microns below the surface  1010 . Accordingly, an increase in pressure during the processes described herein can deform grains at increasing depths from the surface. In this particular example, the grains  1006  that are more than 5 microns below the surface  1010  can be elongated grains  1006 , for example, as described with respect to  FIGS.  15 A- 15 D . Without wishing to be bound by any one theory, it is believed that the increased deformation depth of the grains of the sample  1000  can increase the corrosion resistance and hardness of the sample  1000 . 
     Any number or variety of electronic device components can include a component that has been subjected to a surface treatment, as described herein. The surface treatment or treatments can refine or modify a microstructure of some or all of the component, can densify or reduce the porosity of some or all of the component, and/or can align or reduce gaps between portions of the component. One or more of these surface treatments can include plastically deforming the surface to a desired depth, and/or applying a desire amount of pressure to the surface, as described herein. The component can then be treated, for example, by polishing or forming a surface layer. Various examples of components having been subjected to surface treatments as described herein, surface coatings, and processes for forming the same are described below with reference to  FIG.  17   . 
       FIG.  17    shows a perspective view of a component  1102  of an electronic device. In some examples, the component  1102  can be a band of a smartphone, and can include some or all of the features of the band or enclosure  102 ,  202 ,  302  described herein. In this example, the band  1102  includes a metallic material, such as a stainless steel alloy, and has been subjected to a surface treatment, for example, as described with respect to  FIG.  9 - 11   . The surface treatment has been selectively carried out on corner portions  1122 ,  1124 ,  1126 ,  1128  of the band  1102  that can be prone to experiencing high stress, for example, during drop events. As such, the portions  1122 ,  1124 ,  1126 ,  1128  can include a refined microstructure, as described herein, and can have a first region extending from the exterior surface of the component to a depth of at least about 100 microns having an average grain size less than 45 nanometers. 
     The untreated portions of the band  1102 , meanwhile, can have a substantially unaltered or unaffected grain structure, for example, as illustrated in  FIG.  6   , and including an average grain size greater than 45 or 50 nanometers. Thus, while the portions  1122 ,  1124 ,  1126 ,  1128  can have an increased hardness relative to the untreated portions of the band  1102 , the untreated portions can still be relatively easily machinable. For example, features, such as aperture  1132  through which components can be received, can be machined into the band  1102  after portions  1122 ,  1124 ,  1126 ,  1128  have been formed, but without the need for additional machining time or additional wear on a machining tool. As with the band  302  described above with respect to  FIG.  3   , the band  1102  can be a substantially unitary body, or can include multiple components, such as portions  1112 ,  1114 , that are joined together. Similarly, a feature such as aperture  1134  can be formed in another untreated area of the band  1102 . Although four separate portions  1122 ,  1124 ,  1126 ,  1128  including a refined microstructure as described herein are shown in  FIG.  17   , in some examples, a component can include any number of portions, and each portion can be any desired size or area. Further, in some examples, an entire surface of the component  1102  that defines an exterior portion of the electronic device can include a refined grain structure, as defined herein. 
     Any number or variety of electronic device components can include a component that has been subjected to a surface treatment, as described herein. The surface treatment or treatments can refine or modify a microstructure of some or all of the component, can densify or reduce the porosity of some or all of the component, and/or can align or reduce gaps between portions of the component. One or more of these surface treatments can include plastically deforming the surface to a desired depth, and/or applying a desire amount of pressure to the surface, as described herein. The component can then be treated, for example, by polishing or forming a surface layer. Various examples of components having been subjected to surface treatments as described herein, surface coatings, and processes for forming the same are described below with reference to  FIGS.  18 A- 20   . 
       FIG.  18 A  shows a plot of yield strength as a function of radial depth for a component of an electronic device including a metallic material, such as stainless steel, having a diameter of 40 microns and having a 2 micron thick ceramic PVD layer formed on the component. The plot is the result of a finite element analysis model of a simulated localized high-stress event, such as an impact. Further, the metallic material of the component has not been subjected to any surface treatment and does not include a refined microstructure. Accordingly, there is a large mismatch in the hardness of the PVD layer and the material of the component, as described herein. 
     The interface between the component and the PVD layer is at location 0.04 mm on the right side of the plot. The interfacial stress between the component and the PVD layer during the simulated impact was calculated to be approximately 3.5 GPa. As can be seen from the sharp increase in yield strength to 4 GPa, the intrinsic yield strength of the PVD layer, at location 0.04 mm, the PVD layer has not effectively transferred any load to the metallic component and has experienced a brittle failure, likely due to the mismatch in hardness between the metallic component and the PVD layer. 
       FIG.  18 B  also shows a plot of yield strength as a function of radial depth for a component of an electronic device including a metallic material, such as stainless steel, having a diameter of 40 microns and having a 2 micron thick ceramic PVD layer formed on the component. In the example of  FIG.  18 B , however, the component includes a refined microstructure, as described herein, and thus, includes a region having an increased hardness relative to the untreated metallic material. Thus, the hardness mismatch between the PVD layer and the metallic material at the interface is reduced. 
     This is shown in the plot as an upward curve of the yield strength near to the interface between the metallic material and the PVD layer, indicating that load was transferred from the PVD layer to the metallic material without complete failure of the PVD layer. As a result, the calculated interfacial stress was found to be approximately 2.4 GPa, a reduction of over 1 GPa relative to an untreated component. Accordingly, in some examples, an interfacial stress between a region of the component having a refined microstructure as described herein and a layer formed on the component, such as a ceramic PVD layer, during an impact on the layer can be less than an interfacial stress between the layer and a metallic component that does not have a refined grain structure and that has an average grain size greater than, for example, 45 microns. 
       FIG.  19    shows a plot of hardness (represented as a Vicker&#39;s hardness number, or VHN) as a function of depth for sample components of an electronic device having been subjected to a treatment, as described herein. The components can include some or all of the features of the components  102 ,  202 ,  300 ,  402 ,  502 ,  700 ,  902  as described herein. In this example, a first sample was work-hardened to a half-hard state prior to being subjected to the refining treatment, while a second sample was subjected to an annealing process. Accordingly, the untreated material of the first sample has a hardness  1201  of about 310 VHN (3.1 GPa) through the entire depth of the sample, while the untreated material of the second sample has a hardness  1203  of about 170 VHN (1.7 GPa) through the entire depth of the sample. 
     As can been seen in  FIG.  19   , the refining treatment has affected the grain sizes, and thus hardness  1202  of the material of the first sample extending to a depth of about 700 microns from the surface of the component. In this example, the material at the surface of the first sample has a hardness  1202  of about 450 VHN (4.4 GPa), an increase of about 140 VHN (1.4 GPa) over the untreated material. Further, the hardness  1202  of the material decreases along an approximately linear gradient towards the interior of the first sample component, until a depth of approximately 700 microns. Thereafter, the material has been substantially unaffected by the surface treatment process. 
     For comparison,  FIG.  19    shows a plot of hardness  1204  as a function of depth for the second sample component of an electronic device having been subjected to an annealing process and a surface treatment as described herein. The component and material of the second sample can be substantially identical to the component of the first sample, with the only difference being the treatment processes involved. As can be seen, the resultant surface hardness  1204  of the treated second sample is comparable to the treated first sample at about 400 VHN (3.9 GPa). The annealed second example component includes a much larger drop-off in hardness, with the bulk material only having a hardness  1204  of around 160 KHN (1.6 GPa). Further, the annealed component was exposed to high levels of heat during the annealing process, meaning that any parts unable to withstand this heat could not have been integrated with the component prior to treatment. In contrast, the treatment of the first example component does not require heat or thermal energy, and can be carried out on a component that has been integrated with any number of other components, even components formed of relatively low-melting point materials, such as polymers. 
       FIG.  20    shows a plot of potential (V SCE ) as a function of current density (μA/cm2) for a first sample  1301  and a second sample  1302  undergoing a corrosion resistance test in a saline solution. Each sample included stainless steel, however the first sample  1301  was subjected to a surface treatment, as described herein, while the second sample  1302  was not. As can be seen, the untreated sample has a critical crevice potential  1320  of about 0.5 to about 0.8 V. The critical crevice potential is the potential, or voltage, required to initiate corrosion in a crevice of the sample exposed to an electrolyte, such as saline. In general, the higher the critical crevice potential of a sample, the more resistant to everyday environmental corrosion the sample will be. 
     Further, once this corrosion has begun, a lower potential  1320  can drive the corrosion. In contrast, the treated sample  1301  is substantially more resistant to pitting and the test was unable to reach a critical crevice potential. Instead, only passive corrosion  1310  occurred, independent of the potential. Thus, a metallic sample or component subjected to a surface treatment process as described herein can be substantially more corrosion resistant than an untreated sample or component. 
       FIG.  21    is an X-ray diffractogram for a component of an electronic device both before and after a surface treatment process, as described herein. In this example, the component includes a 316 L alloy of stainless steel, and the untreated component has less than about 1 volume percent martensite. As can been seen in the plot, none of the peaks associated with martensitic steel are present in the untreated steel, indicated here with a solid line. After being subjected to treatment, the (220) peak has increased, however there are still no peaks associated with martensitic steel. Accordingly, the surface treatments described herein can be carried out with the undesirable formation of martensitic phases, which can undesirable impact the magnetic properties of the component, for example, by decreasing the magnetic permeability thereof. Various examples of processes for forming the same are described below with reference to  FIGS.  22 - 23   . 
       FIG.  22    illustrates a process flow diagram of an exemplary process for refining the grains of a component including a metallic material, as described herein. The process  1400  for refining the grains of a region of the component can include translatably contacting a tool to the surface of the component to plastically deform the surface to a desired depth at block  1410 , and forming a first region extending from the surface to a second desired depth, the first region having a smaller average grain size than a second region extending from the first region into the component at block  1420 . 
     At block  1410 , a tool is translatably contacted to the surface of the component at a desired location, for example, as described above with reference to  FIGS.  9 - 11   . The tool can plastically deform the surface to a depth of at least 12 microns, at least 15 microns, at least 20 microns, at least 25 microns, at least 30 microns, at least 40 microns, or at least 50 microns or more. Further, in some examples, the depth to which the tool plastically deformed the surface can be varied at various desired locations. The tool can be translated, for example, by sliding, grinding, or rolling at a desired rate. The tool can include a contact portion that is substantially similar to and can include any of the features of the contact portion  710  described with respect to  FIGS.  9 - 11   . A contact area of the tool on the surface can be less than 500 square microns. In some examples, the contact area can be less than 400 square microns, less than 300 square microns, less than 250 square microns, less than 200 square microns, less than 150 square microns, or less than 100 square microns. 
     At block  1420 , a first region extending from the contacted surface to a second desired depth is formed. Although depicted as a separate process step, in some examples, the formation can occur concurrently or simultaneously with the contacting of the tool to the surface, as mentioned in block  1410 . The first region can extend to a depth of at least 100 microns, for example, to a depth of 300 microns. In some examples, the first region can extend to a depth of at least 150 microns, at least 200 microns, at least 250 microns, at least 300 microns, at least 400 microns, at least 500 microns, at least 600 microns, at least 700 microns, at least 800 microns, at least 900 microns, or even up to 1 mm into the component from the surface. 
     In some examples, the first region can have an average grain size less than a desired size, such as less than 45 nanometers as described herein. A second region having an average grain size greater than a desired size, for example greater than 45 nanometers, can extend from the first region further into the component, as described herein. Additionally, the process  1400  can optionally be repeated a number of times over the same area or surface of a component to further refine the grains thereof. For example, blocks  1410  and  1420  can be repeated once, twice, or even up to 15 times or more in order to form a first region extending a desired depth into the component and having an average grain size less than a desired size, such as less than 45 nanometers. 
       FIG.  23    illustrates a process flow diagram of an exemplary process for treating a component including a metallic material, as described herein. The process  1500  can include translatably contacting a tool to the surface of the component to plastically deform the surface to a desired depth at block  1510  and forming a first region extending from the surface to a second desired depth, the first region having a smaller average grain size than a second region extending from the first region into the component at block  1520 , and forming a layer on the surface of the component by a deposition process at block  1530 . 
     In some examples, blocks  1510  and  1520  can be substantially identical to, and can include some or all of the features of blocks  1410  and  1420 , described with respect to  FIG.  22   . At block  1530 , a layer is formed over the surface by a deposition process. In some examples, the layer can be formed by a vapor deposition process, such as a physical vapor deposition process or a chemical vapor deposition process. In some examples, the layer can have any desired thickness and can be up to 10 microns, 20 microns, 50 microns, 100 microns, 250 microns, 500 microns, or more in thickness. In some examples, the layer can include a ceramic material, such as a carbide, a nitride, or a carbonitride. In some examples, the layer can include titanium carbonitride, chromium carbonitride, or combinations thereof. 
     Any number or variety of electronic device components can include a component that has been subjected to a surface treatment, as described herein. The surface treatment or treatments can refine or modify a microstructure of some or all of the component, can densify or reduce the porosity of some or all of the component, and/or can align or reduce gaps between portions of the component. One or more of these surface treatments can include plastically deforming the surface to a desired depth, and/or applying a desire amount of pressure to the surface, as described herein. The component can then be treated, for example, by polishing or forming a surface layer. Various examples of components having been subjected to surface treatments as described herein, surface coatings, and processes for forming the same are described below with reference to  FIGS.  24 A and  24 B . 
       FIG.  24 A  shows a perspective view of a component  1602  of an electronic device. In some examples, the component  1602  can be a band of a smartphone, and can include some or all of the features of the band or enclosure  102 ,  202 ,  302  described herein. In this example, the band  1602  includes sidewall components  1604 ,  1606 ,  1608 ,  1610 . These sidewall components  1604 ,  1606 ,  1608 ,  1610  can be joined together by a material  1614 . The material  1614  can be any material as desired, for example, a non-conductive material such as a non-conductive polymer. In this example, and as shown, the components  1604 ,  1606 ,  1608 ,  1610  can be integrated with, or joined by, the material  1614  prior to being subjected to a surface treatment. In some examples, the material  1614  can be injection molded into one or more retention features defined by the components  1604 ,  1606 ,  1608 ,  1610  to join the components  1604 ,  1606 ,  1608 ,  1610  together. 
     As can be seen in the inset of  FIG.  24 A , in some examples this molding process can leave a gap, opening, and/or crevice  1622  between the component  1608  and the material  1614 . A gap  1624  can also exist, or be defined by the component  1610  and the material  1614 . Further, the portion  1615  of the exterior surface defined by the material  1614  may, in some examples, be misaligned with the portions  1609 ,  1611  of the exterior surface defined by the metallic surfaces of the components  1608 ,  1610 . That is, the portions  1609 ,  1611 ,  1615  of the exterior surface defined by the material  1614  and components  1608 ,  1610  may not be aligned in a single plane. While the misalignment between the surface  1615  and the surfaces  1609 ,  1611 , and the gaps  1622 ,  1624  may be relatively small and even substantially imperceptible to a human, for example, on the order 10 s or 100 s of microns, the surface offset and gaps can provide ingress points for corrosive or other undesirable materials that can affect the aesthetics and/or function of the component  1602  over time. Accordingly, in some examples, a surface treatment as described herein can serve to align the surfaces  1615 ,  1609 ,  1611  and to close or reduce the size of the gaps  1622 ,  1624 . 
       FIG.  24 B  shows the example component  1602  after having been subjected to a surface treatment as described herein. In some examples, a surface treatment can include contacting the surface  1609  of the metallic portion  1608  with a tool at a desired pressure to deform the portion  1608  to a desired depth, as described with respect to  FIGS.  9 - 11   . The tool can be translated across the surface  1609 , and subsequently across the surface  1615  and  1611 , as described herein. That is, the tool can translate from left to right across the surfaces  1609 ,  1615 ,  1611  as illustrated in  FIG.  24 B . The tool can contact and exert the desired pressure on both the surfaces  1615  and  1611 . While the metallic portions  1609 ,  1611  can be plastically deformed by the surface treatment, in some examples, the surface  1615  and/or non-conductive or polymeric portion  1614  may only be elastically deformed, even though it is subjected to a desired pressure and/or deformed to a same or similar depth as the portions  1608  and  1610 . 
     Accordingly, the plastic deformation of the portions  1608 ,  1610  can serve to align the surfaces  1609 ,  1615 , and  1611  with one another. That is, the surfaces  1609 ,  1615 , and  1611  can be aligned in a single plane and can together define a substantially flat, planar, and/or continuous surface. Further, as shown in  FIG.  24 B , the surface treatment can reduce a size and/or completely close any gaps  1622 ,  1624  between the portions  1608 ,  1610  and the material  1614 . In this way, a surface treatment as described herein can increase a corrosion resistance of a component  1602  by reducing ingress points for contaminants. A surface treatment, as described herein, can also provide a pleasing and desirable aesthetic appearance and feel to the component  1602  by aligning the surfaces thereof. Further, by sealing, closing, or reducing a dimension of the gaps  1622 ,  1624 , a surface treatment can increase a level of water resistance of the component  1602 . 
     Any number or variety of electronic device components can include a component that has been subjected to a surface treatment, as described herein. The surface treatment or treatments can refine or modify a microstructure of some or all of the component, can densify or reduce the porosity of some or all of the component, and/or can align or reduce gaps between portions of the component. One or more of these surface treatments can include plastically deforming the surface to a desired depth, and/or applying a desire amount of pressure to the surface, as described herein. The component can then be treated, for example, by polishing or forming a surface layer. Various examples of components having been subjected to surface treatments as described herein, surface coatings, and processes for forming the same are described below with reference to  FIGS.  25 A- 25 D . 
       FIG.  25 A  shows a perspective view of a component  1702  of an electronic device. In some examples, the component  1702  can be a band of a smartphone, and can include some or all of the features of the band or enclosure  102 ,  202 ,  302  described herein. In this example, the band  1702  includes sidewall components  1704 ,  1706 ,  1708 ,  1710 . These sidewall components  1704 ,  1706 ,  1708 ,  1710  can be joined together by a material  1714 . The material  1714  can be any desired material, for example, a non-conductive material such as a non-conductive polymer. In this particular example, the sidewall components  1704 ,  1706 ,  1708 ,  1710  can include steel, such as a stainless steel alloy like 316 L stainless steel. 
     In some examples, the sidewall components  1704 ,  1706 ,  1708 ,  1710  can be formed, at least partially, by casting or any other process whereby molten metal is cooled or solidified to form the components  1704 ,  1706 ,  1708 ,  1710 . As can be seen in the inset section of  FIG.  25 A , this solidification process can result in formation of clusters  1734  of grains of an intermetallic sigma phase of material. These sigma phase grain clusters  1734  can be surrounding by a desirable phase or phases  1732  of the material including component  1710 , for example, a non-martensitic and/or austenitic phase of steel. 
     In some examples, as described herein, it can be desirable to polish a surface of the component  1710 . The sigma phase grain clusters  1734 , however, can be present in the cosmetic plane of the component  1710 , that is the plane that is polished and/or exposed during a polishing process. The sigma phase grain clusters  1734  can be revealed during such processes and can provide an undesirable cosmetic appearance, showing up as spots or splotches. Further, the relatively high hardness of the sigma phase grain clusters  1734  can cause undesirable complications during the polishing process. Accordingly, it can be desirable to reduce or eliminate the presence of the sigma phase grain clusters  1734  through a surface treatment as described herein prior to polishing the component  1710  or prior to subjecting the component to any other processing. 
       FIG.  25 B  shows the translational path  1742  of a tool that is contacting a region of the surface of the component  1710  that includes or overlays sigma phase grain clusters  1734 . The tool can contact the surface and exert a desired pressure thereon and/or deform the surface to a desired depth, as described herein. Further, the tool can be translated or rastered across the surface to ensure that the path  1742  of the tool translates over the sigma phase grain clusters  1734 , or a region of the surface overlaying the sigma phase grain clusters  1734 . 
       FIG.  25 C  shows an alternate translational path  1744  of the tool during a surface treatment as described herein, whereby the path can cross over a single cluster  1734  multiple times during a single process. Although two particular translational paths  1742 ,  1744  are illustrated in  FIGS.  25 B and  25 C , it should be understood that the surface treatments described herein can use or include substantially any desired translational path. 
       FIG.  25 D  shows the component  1710  after having been subjected to a surface treatment, as described herein. As can be seen, the surface treatment can modify the clusters  1734  of sigma phase grains to break apart the clusters  1734  into smaller and/or more spaced apart portions of sigma phase material  1735 . That is, the sigma phase grain clusters  1734  can now have grains of the phase  1732  disposed between at least some of the sigma phase grains of the cluster  1734 , resulting in smaller portions or clusters  1735  of sigma phase grains or material. Further, in some examples, the sigma phase grain clusters  1734  can include sigma phase grains having a first average grain size. This first average grain size can be about 10 microns to about 100 microns, as measured across a major dimension of the sigma phase grains of the cluster  1734 . After being subjected to a surface treatment as described herein, the sigma phase grains can have a reduced second average grain size. In some examples, this reduced second average grain size can be between about 1 micron and about 10 microns, or even smaller. Accordingly, in some examples, the sigma phase grains of the smaller clusters  1735  can also have a reduced average grain size relative to the sigma phase grains of the clusters  1734 . In this way, any subsequent polishing and/or cosmetic processes performed on the surface treated component  1710  can proceed with reduced complications or with reduced undesirable aesthetic properties associated with the clusters  1734 . 
     Any number or variety of electronic device components can include a component that has been subjected to a surface treatment, as described herein. The surface treatment or treatments can refine or modify a microstructure of some or all of the component, can densify or reduce the porosity of some or all of the component, and/or can align or reduce gaps between portions of the component. One or more of these surface treatments can include plastically deforming the surface to a desired depth, and/or applying a desired amount of pressure to the surface, as described herein. The component can then be treated, for example, by polishing or forming a surface layer. Various examples of components having been subjected to surface treatments as described herein, surface coatings, and processes for forming the same are described below with reference to  FIGS.  26 A- 28   . 
       FIG.  26 A  illustrates a cross-sectional view of a portion of a component  1800  of an electronic device that has not been subjected to a surface treatment as described herein. In some examples, the component  1800  can be a housing of an electronic device and can include some or all of the features of the housings  100 ,  200 ,  400  described herein. In some examples, the component  1800  can define an exterior surface  1810 , that can also at least partially define the exterior surface of an electronic device including the component  1800 . The component  1800  can include or be formed from a metallic material, for example, aluminum, steel, titanium, other metals, or alloys thereof. In some examples, the component  1800  can be formed by a powder metallurgy process, such as an additive manufacturing process, a powder forging process, a hot isostatic pressing (HIP) process, a metal injection molding (MIM) process, a selective sintering process, or any other power metallurgy process or combinations thereof. 
     As a result of this formation process, the metallic body of the component  1800  can include or define one or more pores or voids  1802 ,  1804 . In some examples, these pores  1802 ,  1804  can be substantially evenly distributed throughout the component  1800 . In some examples, as described herein, it can be desirable to polish or perform other treatment processes on the component  1800 . Such processes can result in the removal of material from the surface  1810  to form a new or polished cosmetic surface. Owing to the location of the pores  1802  near the surface  1810 , however, these processes can remove the material overlaying the pores  1802 , thereby revealing the pores  1802  at the cosmetic surface. The revealed pores  1802  can show up as divots or undesirable cosmetic defects on the cosmetic surface after a polishing or another treatment process. Accordingly, it can be desirable to subject the component  1800  to a surface treatment as described herein to reduce the porosity of the component in a region adjacent to the surface  1810  in order to provide a relatively defect or divot free cosmetic surface after polishing or other treatments have been carried out. 
       FIG.  26 B  illustrates the portion of the component  1800  shown in  FIG.  26 A  after having been subjected to a surface treatment, as described herein. For example, after having a tool contact the surface  1810  to exert a desired amount of pressure and/or deform the component  1810  to a desired depth, as described herein. As can be seen, after having been subjected to such a surface treatment, the metallic body of the component  1800  can include a first region  1812  extending from the surface  1810  to a depth below the surface that has a reduced porosity relative to a second region adjacent to and/or below the first region  1812 . In some examples, the first region can extend a depth of at least 50 microns, at least 100 microns, at least 150 microns, at least 200 microns, at least about 400 microns, at least about 600 microns, at least about 800 microns, or even at least about 1 mm. 
     In some examples, the first region  1812  can define fewer pores  1802  per volume relative to the number of pores  1804  per volume in the second region adjacent to the first region  1812 . That is, in some examples, the average porosity of the first region can be less than a desired porosity, while the average porosity of the second region can be greater than the desired porosity. Further, in some examples, the pores  1802  of the first region can be reduced in size by the surface treatment processes described herein. Accordingly, the pores  1802  of the first region can have a smaller or reduced average size relative to the pores  1804  of the second region. 
     In some examples, the first region can have fewer than 100,000 pores per cubic millimeter, fewer than 10,000 pores per cubic millimeter, or fewer than 1000 pores per cubic millimeter. In some examples, the first region can have an average pores size of less than about 10 microns, less than about 5 microns, less than about 3 microns, less than about 2 microns, or even less than about 1 micron or smaller. In some examples, the first region can have a porosity of about 2% or less, about 1.5% or less, about 1% or less, about 0.75% or less, about 0.5% or less, about 0.25% or less, about 0.1% or less, or even about 0.05% or less. 
       FIG.  26 C  shows a cross-sectional view of the portion of the component  1800  of  FIG.  26 B  after being subjected to a polishing process, or any other surface treatment or removal process. As can be seen, a region  1814  of the component  1800  can be removed from the surface to define or reveal a cosmetic surface  1816 . Because the region  1814  is part of the first region  1812 , and has a reduced or lowered porosity, the surface  1816  can be substantially free of revealed pores  1802 . Whereas polishing the component  1800  shown in  FIG.  26 A  may reveal pores  1802  as divots or other undesirable surface features, as can be seen in  FIG.  26 C , the region  1814  can have a substantially reduced porosity, and thus the cosmetic surface  1816  of the component  1800  can have a reduced number of divots or undesirable defects caused by pores as compared to the a component  1800  that has not undergone a surface treatment as described herein. As used herein, the term porosity can refer to a volume percentage of the component that comprises or includes pores or voids. Meanwhile, the density of a sample can be the volume percentage of the sample that includes solid material. The porosity of a sample can also be 100%, less the density of the material. That is, a sample with a porosity of 1% can have a density of 99%. 
       FIG.  27    shows cross-sectional photographs of portions of a first sample component  1901  and a second sample component  1902  before and after being subjected to surface treatments described herein. The cross-sectional photographs on the left show first and second sample components  1901 ,  1902  that have been formed by a metal injection molding (MIM) process. As can be seen, the components  1901 ,  1902  define a number of pores that are distributed throughout the shown cross-sectional area, and can extend from the surface (a depth of 0 microns) to a depth of 315 microns. Each sample was then subjected to a surface treatment as described herein, with a first sample  1901  being subjected to a process wherein a tool exerted a pressure of about 100 bar on the surface thereof, and the second sample  1902  being subjected to a process wherein a tool exerted a pressure of about 300 bar on the surface thereof. 
     The cross-sectional photographs on the right of  FIG.  27    shows the samples  1901 ,  1902  after being subjected to the presently described surface treatment processes. As can be seen, the porosity of the samples  1901 ,  1902  has been reduced in a region extending from the surface to a depth below the surface. In the first sample  1901 , the porosity is reduced in a region extending to a depth of about 20 to 50 microns. Further, as can be seen, both the size and number of pores in this region are reduced relative to the remainder of the sample  1901 . The sample  1902  shows an even greater reduction in porosity and also includes a deeper or larger region of reduced porosity because of the higher pressure exerted by the tool during the surface treatment. As can be seen, the porosity of the region extending from the surface to a depth of about 150 microns has been greatly reduced relative to the untreated sample  1902  and as compared to the region below the reduced porosity region. 
       FIG.  28    shows graphs of porosity, average pore size, and number of pores versus depth for MIM sample components  2001  including a 316 L steel and MIM sample component  2002  including a relatively high nitrogen content steel alloy. The porosity, average pore size, and number of pores were measured for the samples  2001 ,  2002  prior to being subjected to any surface treatment process (labelled as Pre-Burnish), samples  2001 ,  2002  that had been subjected to a surface treatment process that exerted 100 bar of pressure on the samples (labelled as 100 Bar Burnish) and samples  2001 ,  2002  that had been subjected to a surface treatment process that exerted 300 bar of pressure on the samples (labelled as 300 Bar Burnish). As can be seen, the porosity, average pore size, and number of pores in the samples  2001 ,  2002  were reduced after the samples  2001 ,  2002  were subjected to the surface treatment processes described herein. The porosity, average pore size, and number of pores in the samples  2001 ,  2002  were also reduced in regions extending from the surface to depths of at least 50 microns, at least 150 microns, or even 250 microns or greater. 
     Any number or variety of electronic device components can include a component that has been subjected to a surface treatment, as described herein. The surface treatment or treatments can refine or modify a microstructure of some or all of the component, can densify or reduce the porosity of some or all of the component, and/or can align or reduce gaps between portions of the component. One or more of these surface treatments can include plastically deforming the surface to a desired depth, and/or applying a desired amount of pressure to the surface, as described herein. The component can then be treated, for example, by polishing or forming a surface layer. Various examples of components having been subjected to surface treatments as described herein, surface coatings, and processes for forming the same are described below with reference to  FIGS.  29 - 31 B . 
       FIG.  29    illustrates a process flow diagram of an exemplary process  2100  for treating a component including a metal portion and a non-metal, or polymer portion, as described herein. The process  2100  for surface treating the component can include translatably contacting a tool to the surface of the component to plastically deform the surface of the metallic portion to a desired depth at block  2110 , and aligning the surface of the metal portion with a surface of the polymer portion at block  2120 . 
     At block  2110 , a tool is translatably contacted to the surface or surfaces of the component at a desired location, for example, as described above with reference to  FIGS.  9 - 11    and  FIGS.  24 A- 24 B . The tool can plastically deform the surface of the metallic portion, or metallic surface, to a depth of at least 12 microns, at least 15 microns, at least 20 microns, at least 25 microns, at least 30 microns, at least 40 microns, or at least 50 microns or more. Further, in some examples, the depth to which the tool plastically deforms the metallic surface can be varied at various desired locations or portions. The tool can be translated, for example, by sliding, grinding, or rolling at a desired rate. The tool can include a contact portion that is substantially similar to, and can include any of the features of, the contact portion  710  described with respect to  FIGS.  9 - 11   . A contact area of the tool on the surface can be less than 500 square microns. In some examples, the contact area can be less than 400 square microns, less than 300 square microns, less than 250 square microns, less than 200 square microns, less than 150 square microns, or less than 100 square microns. 
     At block  2120 , the metal portion is plastically deformed to align the surface of the metal portion with surface of the polymer portion, for example, as described with respect to  FIG.  24 B . In some examples, the surfaces of the metal portion and the polymer portion can be aligned in or with a single plane. In some examples, the component being subjected to the surface treatment  2100  can include multiple metal portions adjacent to one or more polymer portions, and the surfaces of each of these portions can be aligned. Further, as described with respect to  FIG.  24 B , in some examples, block  2120  can include reducing a size of, and/or closing any gaps between, a metal portion and a non-metal or polymer portion of the component. 
       FIG.  30    illustrates a process flow diagram of an exemplary process  2200  for treating a component including grains of a first phase, such as an intermetallic sigma phase, at least partially surrounded by grains of a second phase, such as a metallic austenitic phase. The process  2200  for surface treating the component can include translatably contacting a tool to the surface of the component to plastically deform the surface of the metallic portion to a desired depth at block  2210 , and as described with respect to  FIGS.  25 A- 25 C . The process  2200  can also include modifying a cluster of grains of the first phase so that grains of the second phase are disposed between at least some of the grains of the first phase at block  2220 , and as described with respect to  FIG.  25 D . In some examples, block  2220  can further include reducing an average grain size of the grains of the first phase positioned at or underlying a region of the surface being contacted at block  2210 , as described with respect to  FIG.  25 D . 
       FIG.  31 A  illustrates a process flow diagram of an exemplary process  2300  for surface treating a component having a first porosity and formed by a powder metallurgy process, as described herein. The process  2300  can include translatably contacting a tool to the surface of the component to plastically deform the surface to a desired depth at block  2310 , and forming a first region extending from the surface to a first depth, the first region having a second smaller porosity, average pore size, and/or number of pores than a second region extending from the first region into the component, at block  2320  and as described with respect to  FIGS.  26 A- 28   . 
       FIG.  31 B  illustrates a process flow diagram of an exemplary process  2400  for surface treating a component having a first porosity and formed by a powder metallurgy process, as described herein. The process  2400  can include translatably contacting a tool to the surface of the component to plastically deform the surface to a desired depth at block  2410 , forming a first region extending from the surface to a first depth, the first region having a second smaller porosity, average pore size, and/or number of pores than a second region extending from the first region into the component, at block  2420  and as described with respect to  FIGS.  26 A- 28   , and removing a portion of material from the first region, for example through a polishing process, the portion extending from the surface to a second depth that is less than the first depth. 
     Any of the features or aspects of the components discussed herein can be combined or included in any varied combination. For example, the design and shape of the component is not limited in any way and can be formed by any number of processes, including those discussed herein. Further, a component including any of the features and/or structures described herein can be formed by any method now known or discovered in the future, even during formation of the component itself. A component including a portion or portions having a refined grain structure, modified porosity, modified grains structure, and/or any other features, as discussed herein, can be or can form all or a portion of a component, such as a housing or enclosure, for an electronic device. The component can also be or form any number of additional components of an electronic device, including internal components, external components, cases, surfaces, or partial surfaces. 
     To the extent applicable to the present technology, gathering and use of data available from various sources can be used to improve the delivery to users of invitational content or any other content that may be of interest to them. The present disclosure contemplates that in some instances, this gathered data may include personal information data that uniquely identifies or can be used to contact or locate a specific person. Such personal information data can include demographic data, location-based data, telephone numbers, email addresses, TWITTER® ID&#39;s, home addresses, data or records relating to a user&#39;s health or level of fitness (e.g., vital signs measurements, medication information, exercise information), date of birth, or any other identifying or personal information. 
     The present disclosure recognizes that the use of such personal information data, in the present technology, can be used to the benefit of users. For example, the personal information data can be used to deliver targeted content that is of greater interest to the user. Accordingly, use of such personal information data enables users to calculated control of the delivered content. Further, other uses for personal information data that benefit the user are also contemplated by the present disclosure. For instance, health and fitness data may be used to provide insights into a user&#39;s general wellness or may be used as positive feedback to individuals using technology to pursue wellness goals. 
     The present disclosure contemplates that the entities responsible for the collection, analysis, disclosure, transfer, storage, or other use of such personal information data will comply with well-established privacy policies and/or privacy practices. In particular, such entities should implement and consistently use privacy policies and practices that are generally recognized as meeting or exceeding industry or governmental requirements for maintaining personal information data private and secure. Such policies should be easily accessible by users and should be updated as the collection and/or use of data changes. Personal information from users should be collected for legitimate and reasonable uses of the entity and not shared or sold outside of those legitimate uses. Further, such collection/sharing should occur after receiving the informed consent of the users. Additionally, such entities should consider taking any needed steps for safeguarding and securing access to such personal information data and ensuring that others with access to the personal information data adhere to their privacy policies and procedures. Further, such entities can subject themselves to evaluation by third parties to certify their adherence to widely accepted privacy policies and practices. In addition, policies and practices should be adapted for the particular types of personal information data being collected and/or accessed and adapted to applicable laws and standards, including jurisdiction-specific considerations. For instance, in the US, collection of or access to certain health data may be governed by federal and/or state laws, such as the Health Insurance Portability and Accountability Act (HIPAA); whereas health data in other countries may be subject to other regulations and policies and should be handled accordingly. Hence different privacy practices should be maintained for different personal data types in each country. 
     Despite the foregoing, the present disclosure also contemplates embodiments in which users selectively block the use of, or access to, personal information data. That is, the present disclosure contemplates that hardware and/or software elements can be provided to prevent or block access to such personal information data. For example, in the case of advertisement delivery services, the present technology can be configured to allow users to select to “opt in” or “opt out” of participation in the collection of personal information data during registration for services or anytime thereafter. In another example, users can select not to provide mood-associated data for targeted content delivery services. In yet another example, users can select to limit the length of time mood-associated data is maintained or entirely prohibit the development of a baseline mood profile. In addition to providing “opt in” and “opt out” options, the present disclosure contemplates providing notifications relating to the access or use of personal information. For instance, a user may be notified upon downloading an app that their personal information data will be accessed and then reminded again just before personal information data is accessed by the app. 
     Moreover, it is the intent of the present disclosure that personal information data should be managed and handled in a way to minimize risks of unintentional or unauthorized access or use. Risk can be minimized by limiting the collection of data and deleting data once it is no longer needed. In addition, and when applicable, including in certain health related applications, data de-identification can be used to protect a user&#39;s privacy. De-identification may be facilitated, when appropriate, by removing specific identifiers (e.g., date of birth, etc.), controlling the amount or specificity of data stored (e.g., collecting location data a city level rather than at an address level), controlling how data is stored (e.g., aggregating data across users), and/or other methods. 
     Therefore, although the present disclosure broadly covers use of personal information data to implement one or more various disclosed embodiments, the present disclosure also contemplates that the various embodiments can also be implemented without the need for accessing such personal information data. That is, the various embodiments of the present technology are not rendered inoperable due to the lack of all or a portion of such personal information data. For example, content can be selected and delivered to users by inferring preferences based on non-personal information data or a bare minimum amount of personal information, such as the content being requested by the device associated with a user, other non-personal information available to the content delivery services, or publicly available information. 
     As used herein, the terms exterior, outer, interior, inner, top, and bottom are used for reference purposes only. An exterior or outer portion of a component can form a portion of an exterior surface of the component but may not necessarily form the entire exterior of outer surface thereof. Similarly, the interior or inner portion of a component can form or define an interior or inner portion of the component but can also form or define a portion of an exterior or outer surface of the component. A top portion of a component can be located above a bottom portion in some orientations of the component, but can also be located in line with, below, or in other spatial relationships with the bottom portion depending on the orientation of the component. 
     Various inventions have been described herein with reference to certain specific embodiments and examples. However, they will be recognized by those skilled in the art that many variations are possible without departing from the scope and spirit of the inventions disclosed herein, in that those inventions set forth in the claims below are intended to cover all variations and modifications of the inventions disclosed without departing from the spirit of the inventions. The terms “including:” and “having” come as used in the specification and claims shall have the same meaning as the term “comprising.” 
     The foregoing description, for purposes of explanation, used specific nomenclature to provide a thorough understanding of the described embodiments. However, it will be apparent to one skilled in the art that the specific details are not required in order to practice the described embodiments. Thus, the foregoing descriptions of the specific embodiments described herein are presented for purposes of illustration and description. They are not targeted to be exhaustive or to limit the embodiments to the precise forms disclosed. It will be apparent to one of ordinary skill in the art that many modifications and variations are possible in view of the above teachings.

Metadata:
Filing Date: 20210830
Publication Date: 20240514
Grant Date: 20240514
Priority Date: 20200923
Inventors: JOU, HERNG-JENG
LI, HOISHUN
YURKO, JAMES A.
Assignee: APPLE INC
CPC Classifications: [{"code": "H05K5/0286", "inventive": true, "first": true, "tree": "[]"}, {"code": "B21D22/02", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04M1/026", "inventive": false, "first": false, "tree": "[]"}, {"code": "B22F3/225", "inventive": true, "first": true, "tree": "[]"}, {"code": "G06F1/1626", "inventive": true, "first": true, "tree": "[]"}, {"code": "H05K5/0286", "inventive": true, "first": true, "tree": "[]"}, {"code": "B22F3/24", "inventive": true, "first": false, "tree": "[]"}, {"code": "C21D7/04", "inventive": true, "first": false, "tree": "[]"}, {"code": "C22F1/04", "inventive": true, "first": false, "tree": "[]"}, {"code": "H05K5/0217", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04M1/18", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04M1/0202", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F1/1656", "inventive": true, "first": false, "tree": "[]"}, {"code": "C22F1/00", "inventive": true, "first": false, "tree": "[]"}, {"code": "C21D7/06", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04M1/026", "inventive": false, "first": false, "tree": "[]"}, {"code": "B21D22/02", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 80741888