Patent ID: 12186791

DESCRIPTION

This disclosure is submitted in furtherance of the constitutional purposes of the U.S. Patent Laws “to promote the progress of science and useful arts” (Article 1, Section 8).

The following description including the attached pages provide various examples of the present invention. It will be clear from this description of the invention that the invention is not limited to these illustrated embodiments but that the invention also includes a variety of modifications and embodiments thereto. Therefore, the present description should be seen as illustrative and not limiting. While the invention is susceptible to various modifications and alternative constructions, it should be understood, that there is no intention to limit the invention to the specific form disclosed, but, on the contrary, the invention is to cover all modifications, alternative constructions, and equivalents falling within the spirit and scope of the invention as defined in the claims.

In the previously described and related applications various methods and techniques are described wherein the described technique and device (referred to as ShAPE) is shown to provide a number of significant advantages including the ability to control microstructure such as crystallographic texture through the cross sectional thickness, while also providing the ability to perform various other tasks. In this description we provide information regarding the use of the ShAPE technique to form materials with non-circular hollow profiles as well as methods for creating high entropy alloys that are useful in a variety of applications such as projectiles. Exemplary applications will be discussed on more detail in the following.

Referring first now toFIGS.1aand1b, examples of the ShAPE device and arrangement are provided. In an arrangement such as the one shown inFIG.1A, rotating die10is thrust into a material20under specific conditions whereby the rotating and shear forces of the die face12and the die plunge16combine to heat and/or plasticize the material20at the interface of the die face12and the material20and cause the plasticized material to flow in desired direction in either a direct or indirect manner. (In other embodiments the material20may spin and the die10pushed axially into the material20so as to provide this combination of forces at the material face.) In either instance, the combination of the axial and the rotating forces plasticize the material20at the interface with the die face12. Flow of the plasticized material can then be directed to another location wherein a die bearing surface24of a preselected length facilitates the recombination of the plasticized material into an arrangement wherein a new and more refined grain size and texture control at the micro level can take place. This then translates to an extruded product22with desired characteristics. This process enables better strength, ductility, and corrosion resistance at the macro level together with increased and better performance. This process can eliminate the need for additional heating, and the process can utilize a variety of forms of material including billet, powder or flake without the need for extensive preparatory processes such as “steel canning”, billet pre-heating, de-gassing, de-canning and other process steps can be utilized as well. This arrangement also provides for a methodology for performing other steps such as cladding, enhanced control for through wall thickness and other characteristics, joining of dissimilar materials and alloys, and beneficial feedstock materials for subsequent rolling operations.

This arrangement is distinct from and provides a variety of advantages over the prior art methods for extrusion. First, during the extrusion process the force rises to a peak in the beginning and then falls off once the extrusion starts. This is called breakthrough. In this ShAPE process the temperature at the point of breakthrough is very low. For example for Mg tubing, the temperature at breakthrough for the 2″ OD, 75 mil wall thickness ZK60 tubes is <150 C. This lower temperature breakthrough is believed in part to account for the superior configuration and performance of the resulting extrusion products.

Another feature is the low extrusion coefficient kf which describes the resistance to extrusion (i.e. lower kf means lower extrusion force/pressure). Kf is calculated to be 2.55 MPa and 2.43 MPa for the extrusions made from ZK60-T5 bar and ZK60 cast respectively (2″ OD, 75 mil wall thickness). The ram force and kf are remarkably low compared to conventionally extruded magnesium where kf ranges from 68.9-137.9 MPa. As such, the ShAPE process achieved a 20-50 times reduction in kf (as thus ram force) compared to conventional extrusion. This assists not only with regard to the performance of the resulting materials but also reduced energy consumption required for fabrication. For example, the electrical power required to extrude the ZK60-T5 bar and ZK60 cast (2″ OD, 750 mil wall thickness) tubes is 11.5 kW during the process. This is much lower than a conventional approach that uses heated containers/billets. Similar reductions in kf have also been observed when extruding high performance aluminum powder directing into wire, rod, and tubing.

The ShAPE process is significantly different than Friction Stir Back Extrusion (FSBE). In FSBE, a spinning mandrel is rammed into a contained billet, much like a drilling operation. Scrolled grooves force material outward and material back extrudes around and onto the mandrel to form a tube, not having been forced through a die. As a result, only very small extrusion ratios are possible, the tube is not fully processed through the wall thickness, the extrudate is not able to push off of the mandrel, and the tube length is limited to the length of the mandrel. In contrast, ShAPE utilizes spiral grooves on a die face to feed material inward through a die and around a mandrel that is traveling in the same direction as the extrudate. As such, a much larger outer diameter and extrusion ratio are possible, the material is uniformly process through the wall thickness, the extrudate is free to push off the mandrel as in conventional extrusion, and the extrudate length is only limited only by the starting volume of the billet. ShAPE can be scalable to the manufacturing level, while the limitations of FSBE have kept the technology as a non-scalable academic interest since FBSE was first reported.

An example of an arrangement using a ShAPE device and a mandrel18is shown inFIG.1B. This device and associated processes have the potential to be a low-cost, manufacturing technique to fabricate variety of materials. As will be described below in more detail, in addition to modifying various parameters such as feed rate, heat, pressure and spin rates of the process, various mechanical elements of the tool assist to achieve various desired results. For example, varying scroll patterns14on the face of extrusion dies12can be used to affect/control a variety of features of the resulting materials. This can include control of grain size and crystallographic texture along the length of the extrusion and through-wall thickness of extruded tubing and other features. Alteration of parameters can be used to advantageously alter bulk material properties such as ductility and strength and allow tailoring for specific engineering applications including altering the resistance to crush, pressure or bending. Scrolls patterns have also been found to affect grain size and texture through the thickness of the extrusion.

The ShAPE process has been utilized to form various structures from a variety of materials including the arrangement as described in the following table.

TABLE 1AlloyMaterial ClassPrecursor FormPUCKSBi2Te3ThermoelectricPowderFe—SiMagnetPowderNd2Fe11B/FeMagnetPowderNd2Fe14BMagnetPowderMA956ODS SteelPowderNb 0.95 Ti 0.05 Fe 1 Sb 1ThermoelectricPowderMn—BiMagnetPowderAl—SiModel Binary AlloyPowderCu—NiModel Binary AlloyPowderCu—NbModel Binary AlloyPowderPM 2000ODS SteelPowderEurofer 97ODS SteelPowderTUBESZK60Magnesium AlloyBarstock, CastingAZ31Magnesium AlloyBarstockAZ91Magnesium AlloyFlake, CastingAZS312Magnesium AlloyCastingMg7SiMagnesium AlloyCastingAZ91- 1, 5 and 10 wt. % Al2O3Mg MMCMechanically Alloyed FlakeAZ91- 1, 5 and 10 wt. % Y2O3Mg MMCMechanically Alloyed FlakeAZ91- 1, 5 and 10 and 5 wt. % SiCMg MMCMechanically Alloyed FlakeAA6063Structural AluminumCasting, Barstock and ChipAA7075High Strength AluminumCastingAl-12.4TMHigh Strength AluminumPowderA356Structural AluminumChipRODSAl—Mn wt. 15%Aluminum Manganese AlloyCastingAl—MgMg Al CoextrusionBarstockMg—Dy—Nd—Zn—ZrMagnesium Rare EarthBarstockCuPure CopperBarstockDS—CuDispersion Strengthened CuPowderCu-GraphiteConductive CopperPowderCu-GrapheneConductive CopperPowder + FilmCu-GrapheneConductive CopperBarstock + FilmCu-GrapheneConductive CopperFoil + FilmAl-GrapheneConductive AluminumPowder + FilmAl-Reduced GrapheneConductive AluminumBarstock + FlakeAl-GraphiteConductive AluminumBarstock + PowderMgPure MagnesiumBarstockAA6061AluminumCastingAA7075AluminumCastingAl—Ti—Mg—Cu—FeHigh Entropy AlloyCastingAl- 1, 5, 10 at. % MgMagnesium AlloyCastingAl-12.4TMHigh Strength AluminumPowderRhodiumPure RhodiumBarstockAl—CeHigh Temperature/Strength AluminumCastingAA1100Aluminium AlloyBarstockAA7XXXHigh Strength AluminumProprietary Powder14YWTODS SteelPowderMA956ODS SteelPowder

In addition, to the pucks, rods and tubes described above, the present disclosure also provides a description of the use of a specially configured scroll component referred by the inventors as a portal bridge die head which allows for the fabrication of ShAPE extrusions with non-circular hollow profiles. This configuration allows for making extrusion with non-circular, and multi-zoned, hollow profiles using a specially formed portal bridge die and related tooling.

FIGS.2A-2Cshow various views of a portal bridge die design with a modified scroll face that unique to operation in the ShAPE process.FIG.2Ashows an isometric view of the scroll face on top of the portal bridge die andFIG.2Bshows an isometric view of the bottom of the portal bridge die with the mandrel visible.

In the present embodiment grooves13,15on the face12of the die10direct plasticized material toward the aperture ports17. Plasticized material then passes through the aperture ports17wherein it is directed to a die bearing surface24within a weld chamber similar to conventional portal bridge die extrusion. In this illustrative example, material flow is separated into four distinct streams using four ports17as the billet and the die are forced against one another while rotating.

While the outer grooves15on the die face feed material inward toward the ports17, inner grooves13on the die face feed material radially outward toward the ports17. In this illustrative example, one groove13is feeding material radially outward toward each port17for a total of four outward flowing grooves. The outer grooves15on the die surface12feed material radially inward toward the port17. In this illustrative example, two sets of grooves are feeding material radially inward toward each port17for a total of eight inward feeding grooves15. In addition to these two sets of grooves, a perimeter groove19on the outer perimeter of the die, shown inFIG.2C, is oriented counter to the die rotation so as to provide back pressure thereby minimizing material flash between the container and die during extrusion.

FIG.2Bshows a bottom perspective view of the portal bridge die12. In this view, the die shows a series of full penetration of ports17. In use, streams of plasticized material tunneled by the inward15and outward13directed grooves described above pass through these ports17and then are recombined in a weld chamber21and then flow around a mandrel18to create a desired cross section. The use of scrolled grooves13,15,19to feed the ports17during rotation—as a means to separate material flow of the feedstock (e.g. powder, flake, billet, etc.) into distinct flow streams has never been done to our knowledge. This arrangement enables the formation of items with noncircular hollow cross sections.

FIG.3shows a separation of magnesium alloy ZK60 into multiple streams using the portal bridge die approach during ShAPE processing. (In this case the material was allowed to separate for effect and illustration of the separation features and not passed over a die bearing surface for combination). Conventional extrusion does not rotate and the addition of grooves would greatly impede material flow. But when rotation is present, such as in ShAPE or friction extrusion, the scrolls not only assist flow, but significantly assist the functioning of a portal bridge die extrusion and the subsequent formation of non-circular hollow profile extrusions. Without scrolled grooves feeding the portals, extrusion via the portal bridge die approach using a process where rotation is involved, such as ShAPE, would be ineffective for making items with such a configuration. The prior art conventional linear extrusion process teach away from the use of surface features to guide material into the portals17during extrusion.

In the previously described and related applications various methods and techniques are described wherein the ShAPE technique and device is shown to provide a number of significant advantages including the ability to control microstructure such as crystallographic texture through the cross sectional thickness, while also providing the ability to perform various other tasks. In this description we provide information regarding the use of the ShAPE technique to form materials with non-circular hollow profiles as well as methods for creating high entropy alloys that are useful in a variety of applications. These two exemplary applications will be discussed on more detail in the following.

FIG.4Ashows a schematic of the ShAPE process which utilizes a rotating tool to apply load/pressure and at the same time the rotation helps in applying torsional/shear forces, to generate heat at the interface between the tool and the feedstock and within the material, thus helping to consolidate the material. In this particular embodiment the arrangement of the ShAPE setup is configured so as to consolidate high entropy alloy (HEA) arc-melted buttons into densified pucks. In this arrangement the rotating ram tool is made from an Inconel alloy and has an outer diameter (OD) of 25.4 mm, and the scrolls on the ram face were 0.5 mm in depth and had a pitch of 4 mm with a total of 2.25 turns. In this instance the ram surface incorporated a thermocouple to record the temperature at the interface during processing. (seeFIG.4B) The setup enables the ram to spin at speeds from 25 to 1500 RPM.

In use, both an axial force and a rotational force are applied to a material of interest causing the material to plasticize. In extrusion applications, the plasticized material then flows over a die bearing surface dimensioned so as to allow recombination of the plasticized materials in an arrangement with superior grain size distribution and alignment than what is possible in traditional extrusion processing. As described in the prior related applications this process provides a number of advantages and features that conventional prior art extrusion processing is simply unable to achieve.

High entropy alloys are generally solid-solution alloys made of five or more principal elements in equal or near equal molar (or atomic) ratios. While this arrangement can provide various advantages, it also provides various challenges particularly in forming. While conventional alloys can comprise one principal element that largely governs the basic metallurgy of that alloy system (e.g. nickel-base alloys, titanium-base alloys, aluminum-base alloys, etc.) in an HEA each of the five (or more) constituents of HEAs can be considered as the principal element. Advances in production of such materials may open the doors to their eventual deployment in various applications. However, standard forming processes have demonstrated significant limitations in this regard. Utilization of the ShAPE type of process demonstrates promise in obtaining such a result.

In one example a “low-density” AlCuFe(Mg)Ti HEA was formed. Beginning with arc-melted alloy buttons as a pre-cursor, the ShAPE process was used to simultaneously heat, homogenize, and consolidate the HEA resulting in a material that overcame a variety of problems associated with prior art applications and provided a variety of advantages. In this specific example, HEA buttons were arc-melted in a furnace under 10−6Torr vacuum using commercially pure aluminum, magnesium, titanium, copper and iron. Owing to the high vapor pressure of magnesium, a majority of magnesium vaporized and formed Al1Mg0.1Cu2.5Fe1Ti1.5 instead of the intended Al1Mg1Cu1Fe1Ti1 alloy. The arc melted buttons described in the paragraph above were easily crushed with a hammer and used to fill the die cavity/powder chamber (FIG.4C), and the shear assisted extrusion process initiated. The volume fraction of the material filled was less than 75%, but was consolidated when the tool was rotated at 500 RPM under load control with a maximum pressure set at 85 MPa and at 175 MPa.

Comparison of the arc-fused material and the materials developed under the ShAPE process demonstrated various distinctions. The arc melted buttons of the LWHEA exhibited a cored dendritic microstructure along with regions containing intermetallic particles and porosity. Using the ShAPE process these microstructural defects were eliminated to form a single phase, refined grain and no porosity LWHEA sample

FIG.5shows the backscattered SEM (BSE-SEM) image of the as-cast/arc-melted sample. The arc melted samples had a cored dendritic microstructure with the dendrites rich in iron, aluminum and titanium and were 15-30 μm in diameter, whereas the inter-dendritic regions were rich in copper, aluminum and magnesium. Aluminum was uniformly distributed throughout the entire microstructure. Such microstructures are typical of HEA alloys. The inter-dendritic regions appeared to be rich in Al—Cu—Ti intermetallic and was verified by XRD as AlCu2Ti. XRD also confirmed a Cu2Mg phase which was not determined by the EDS analysis and the overall matrix was BCC phase. The intermetallics formed a eutectic structure in the inter-dendritic regions and were approximately 5-10 μm in length and width. The inter-dendritic regions also had roughly 1-2 vol % porosity between them and hence was difficult to measure the density of the same.

Typically such microstructures are homogenized by sustained heating for several hours to maintain a temperature near the melting point of the alloy. In the absence of thermodynamic data and diffusion kinetics for such new alloy systems the exact points of various phase formations or precipitation is difficult to predict particularly as related to various temperatures and cooling rates. Furthermore, unpredictability with regard to the persistence of intermetallic phases even after the heat treatment and the retention of their morphology causes further complications. A typical lamellar and long intermetallic phase is troublesome to deal with in conventional processing such as extrusion and rolling and is also detrimental to the mechanical properties (elongation).

The use of the ShAPE process enabled refinement of the microstructure without performing homogenization heat treatment and provides solutions to the aforementioned complications. The arc melted buttons, because of the presence of their respective porosity and the intermetallic phases, were easily fractured into small pieces to fill in the die cavity of the ShAPE apparatus. Two separate runs were performed as described in Table 1 with both the processes' yielding a puck with diameter of 25.4 mm and approximately 6 mm in height. The pucks were later sectioned at the center to evaluate the microstructure development as a function of its depth. Typically in the ShAPE consolidation process; the shearing action is responsible for deforming the structure at interface and increasing the interface temperature; which is proportional to the rpm and the torque; while at the same time the linear motion and the heat generated by the shearing causes consolidation. Depending on the time of operation and force applied near through thickness consolidation can also be attained.

TABLE 2Consolidation processing conditions utilized for LWHEAPressureProcessRun #(MPa)Tool RPMTemperatureDwell Time1175500180 s285500600° C.180 s

FIGS.6A-6Dshow a series of BSE-SEM images ranging from the essentially unprocessed bottom of the puck to the fully consolidated region at the tool billet interface. There is a gradual change in microstructure from the bottom of the puck to the interface where shear was applied. The bottom of the puck had the microstructure similar to one described inFIG.5. But as the puck is examined moving towards the interface the size of these dendrites become closely spaced (FIG.6B). The intermetallic phases are still present in the inter-dendritic regions but the porosity is completely eliminated. On the macro scale the puck appears more contiguous and without any porosity from the top to the bottom ¾thsection.FIG.6Cshows the interface where the shearing action is more prominent. This region clearly demarcates the as-cast dendritic structure to the mixing and plastic deformation caused by the shearing action. A helical pattern is observed from this region to the top of the puck. This is indicative of the stirring action and due to the scroll pattern on the surface of the tool. This shearing action also resulted in the comminution of the intermetallic particles and also assisted in the homogenizing the material as shown inFIGS.6C and6D. It should be noted that this entire process lasted only 180 seconds to homogenize and uniformly disperse and comminute the intermetallic particles. The probability that some of these intermetallic particles were re-dissolved into the matrix is very high. The homogenized region was nearly 0.3 mm from the surface of the puck.

The use of the ShAPE device and technique demonstrated a novel single step method to process without preheating of the billets. The time required to homogenize the material was significantly reduced using this novel process. Based on the earlier work, the shearing action and the presence of the scrolls helped in comminution of the secondary phases and resulted in a helical pattern. All this provides significant opportunities towards cost reduction of the end product without compromising the properties and at the same time tailoring the microstructure to the desired properties. Similar accelerated homogenization has also been observed in magnesium and aluminum alloys during ShAPE of as-cast materials.

In as much as types of alloys exhibit high strength at room temperature and at elevated temperature, good machinability, high wear and corrosion resistance, such materials could be seen as a replacement in a variety of applications. A refractory HE-alloy could replace expensive super-alloys used in applications such as gas turbines and the expensive Inconel alloys used in coal gasification heat exchanger. A light-weight HE-alloy could replace aluminum and magnesium alloys for vehicles and airplanes. Use of the ShAPE process to perform extrusions would enable these types of deployments.

Referring next toFIG.7, a device for performing shear-assisted extrusion is disclosed with reference to different implementations A, B, and C. In accordance with example implementations, device100can be a scroll having a scroll face110that includes an inner diameter portion104as well as outer diameter portions106. Accordingly, these 3 scroll faces are shown in accordance with one cross section. As shown and depicted herein, viewed from the face they would have a circular formation. Accordingly, inner diameter portion104can extend beyond a surface110of outer diameter portion106. Devices100can include apertures115arranged within the outer diameter portion and extending through the device toward a side102opposite the scroll face110. As shown and depicted, inner portion104can be defined by the member112extending from surface110. In accordance with alternative implementations, this member112, as well as member114in implementation B and116in implementation C, may not occupy all of inner portion104, but only a portion. In accordance with example implementations, portion104can be rectangular in one cross section, and with reference to implementation B, member114can be trapezoidal in one cross section, and with reference to implementation C, member116can be conical in one implementation. In each of these implementations, the member112,114,116can have sidewalls, and these sidewalls can define structures thereon, for example, these structures can be groves and/or extensions that provide for the transition of material away or towards the perimeter of the scroll face, which then would direct the material being processed through apertures115.

Referring next toFIG.8, an example scroll face device is depicted in isometric view having inner portion104and outer portion106. Accordingly, the device can include raised portions140,142, and/or144. These portions can provide for a flow of material in predetermined direction. For example, portions140can be configured to provide material to within apertures115, while portions142can be configured to provided material to within the same apertures115, thereby providing for flow of materials toward one another. Portions144can be provided for mechanicals needs as the device is utilized.

In accordance with example implementations, Shear assisted processing and extrusion (ShAPE™) can be used to join magnesium and aluminum alloys in a butt joint configuration. Joining can occur in the solid-phase and in the presence of shear, brittle Mg17Al12intermetallic layers can be eliminated from the Mg—Al interface. The joint composition can transition gradually from Mg to Al, absent of Mg17Al12, which can improve mechanical properties compared to joints where Mg17Al12interfacial layers are present.

As alluded to joining Mg—Al is difficult to perform without forming a brittle Mg17Al12interfacial layer at the dissimilar interface. Example applications for material having been joined using the processes of the present disclosure include, but are not limited to:Lightweight of rivets and bolts (i.e. Al shank with Mg head or vice versa)Multi-material extrusion for structural members (tailor welded extrusions)Mg—Al tailor welded blanks formed by slitting and rolling thin-walled tubesCorrosion resistant joints due to galvanically graded Mg—Al interfaceDissimilar Mg alloy or Al alloy joint pairs (i.e. AA6061 to AA7075)
Referring toFIGS.9A-9C, different views of a scroll face or die face of an extrusion die tool are shown including cross sectional views. In accordance with example implementations, the die tool can also be configured with or without scrolls in the die face. For example, when processing high temperature materials like steels, Tungsten Rhenium can be used as the die tool material. This material can engage the feedstock material to the extent that friction or shear is provided thereby producing sufficient deformational heating.

Die tool200can include tool sidewalls202as well as die face rim204. InFIG.9B, die face208can have an opening206configured to receive and extrude feedstock material mixed and provided during the process. Referring next toFIG.9C, from opening206can extend die face208. As shown, die face208can be extended at an angle in relation to rim204or sidewall202. This angle can be greater than zero degrees as shown in table 3; as an example for tubes fabricated with 12 mm outer diameter and 1 mm and 2 mm wall thickness. In accordance with example implementations this angle can form a portion of the die face, a substantial portion of the die face (for example extending greater than 50% of the radius of the die face), and/or an entirety of the die face from rim204to opening206.

TABLE 3Extrusions fabricated with differing degrees of angled scroll faces.Wall Thickness6 Scroll1 and 2 mm4 Scroll, 0 deg1 and 2 mm4 Scroll, 14 deg1 and 2 mm4 Scroll, 26 deg1 and 2 mm4 Scroll, 45 deg1 and 2 mm

Referring next toFIG.10A, in accordance with another example implementation, die200can have an outer rim204can have a portion that is substantially planar in relation to face208thereby providing a substantially normal relationship between face204and sidewall202. As can be seen with respect toFIG.10C, face208can extend at an angle from this rim to opening206, and this angle can be measured to an imaginary extension212as angle210.

Referring next toFIG.11A, a die200is shown with sidewalls202and rim204. Referring toFIG.11B, die200can have a recess214therein about opening206. Recess or bore214can be contiguous with opening206. In accordance with example implementations and with reference toFIG.11C, recess214can extend from the face208into the die along member or face216to a ledge218, and then to opening206. Opening206has been described in relation to a single extrusion; however, opening206can also be a larger opening that can be used in conjunction with a mandrel to provide tubed material as extrusion products, for example.

In accordance with example implementations and with reference toFIGS.12A-12C, die face200can include sidewall202and rim204. As can be seen inFIG.12B, recess214can be defined within die200, and as shown inFIG.12C, face208can be angled in relation to sidewall202and also include recess214having side face216extending to ledge218.

Referring next toFIG.13A, die face200can include sidewall202and rim204. As can be seen, rim204can be substantially planar as shown inFIGS.13B and13C.

Referring next toFIGS.14A-14B, in accordance with example implementations, die200can be used to process feedstock material220. Material220can be a single material or a mix of material as shown with # *, and as the ShAPE process proceeds, the material is sheared and/or plasticized to continue to form extrusion product222. As can be seen, within recess214the material can mix. This mixing can provide for a more homogeneous or stable extrusion product222.

Referring next toFIG.15, in accordance with another example implementation, a die200is shown processing feedstock material220. This die can have an angled face as well as shorter extensions extending to a mandrel configuration, wherein mandrel224extends between extensions226. This mandrel configuration with the shorter extensions can provide for a more stable extrusion product222in the form of a tube, for example. These extensions can be considered a bearing surface.

Referring next toFIGS.16and17, an example die200is shown having face208as well as opening206. In accordance with example implementations, an extrusion product222is shown that can be provided utilizing this die200. Additionally, the feedstock material can be seen, and the extrudate can be seen in accordance withFIG.17.

Referring next toFIG.18, an example die face is shown having a long bearing surface and without a counterbore or recess214. As shown inFIG.19, the die face has a short bearing surface226as well as a recess214within face208. In accordance with example implementations and with reference toFIG.20, utilizing these die faces with the angles and counterbores can provide for reduced extrusion force. As shown inFIG.21, these die faces can provide reduced motor torque.

Referring next toFIG.22, a pair of die faces are compared, one having a flat scrolled die face with a counterbore, and one including a conical die face or angled die face having angle210with a counterbore. Utilizing these die faces, reduced force is provided as shown inFIG.23; reduced torque is provided as shown inFIG.24; and reduced temperature is provided as shown inFIG.25.

Referring next toFIG.26, utilizing the counterbore214and a short bearing surface, a tubular extrusion product having a straight nice finish can be provided as compared to a die face having a longer bearing surface shown above.

Referring next toFIGS.27-28, again with a long bearing surface as shown inFIG.27, the extrusion product is fragile and twisted with a rough surface, whereas the extrusion product prepared using a short bearing surface and a recess is considered fully consolidated and a straight surface.

Referring next toFIGS.29-30, a comparison of extrusion products having different millimeters and different degrees is shown ranging from greater than 0 degrees to at least 45 degrees. Referring next toFIGS.31-33, an example die face is shown inFIG.31, and an improved die face is shown inFIG.32having a flat or planar rim204resulting in an improved product as shown inFIG.33. Referring next toFIGS.34and35, data utilizing the scrolls of the present invention is disclosed.

In accordance with example implementations, materials can be engaged using the ShAPE technology of the present disclosure. For example, Mg alloy ZK60 can be joined to Al alloy 6061, without forming an Mg17Al12interfacial layer. To accomplish this, the ShAPE™ process can be modified to mix ZK60 and AA6061 into a fully consolidated rod having an Al rich coating as a corrosion barrier. Referring next toFIG.36, a 5 mm diameter rod extruded from distinct Mg and Al pucks is shown inFIG.36(A)with full consolidation shown inFIG.36(B), andFIG.36(C)shows a gradient in the composition (magenta Al map) between the Al rich surface and rod interior. Analysis showed the critical result that the Mg17Al12β-phase did not exist as an interfacial layer, rather the IMC was highly refined and dispersed throughout the extrusion.

Referring toFIG.37, an example solid-phase method for joining Mg to Al extrusions in a butt configuration is shown. In accordance with example implementations, separate Mg and Al billets can be interlocked to form a single billet that will be extruded using the ShAPE process for example. As the die rotates and plunges to the right, an Mg alloy extrusion forms as the material is consumed. The rotating die then penetrates into the interlocking region of the two feedstock materials where Mg and Al are mixed and extruded simultaneously to form the dissimilar joint. Once the die penetrates past the interlocking region of the two feedstock materials, an Al alloy extrusion forms as material continues to be consumed. As shown inFIG.38, a multi-material rod or hollow-section extrusion can be fabricated absent of a brittle Mg17Al12interfacial layer is shown. The method can be used for rods and/or tubes of varying diameters.

The geometry of the interlocking region can be tailored to control the composition and transition length of the Mg-Al joint region. The geometric possibilities are many but two examples are shown in window160inFIG.37; one abrupt (flat pie shaped interface having complimentary portions162aand162bthat interlock to form interlocking region163), and one gradual (triangular spokes interface having complimentary portions164aand164bthat interlock to form interlocking region165). The most abrupt interface can be achieved with a flat interface between the Mg and Al billets.

In accordance with at least one implementation, with triangular spoked interlocks165, the composition of Mg in Al goes from 0% to 100% at a rate depending on the number of spokes and angle of the triangle's vertex. This method has been used to demonstrate a transition length of 37 mm to illustrate the concept. Because the joint is formed by mixing in the solid phase, an Mg17Al12interfacial layer will not form. Rather, a gradient in chemical composition and also possibly grain size will form across the dissimilar interface with the intense shear refining and dispersing any Mg17Al12second phase formations. The composition gradient at the Mg—Al interface has a secondary benefit of also being a galvanically graded interface which can improve corrosion resistance. Referring toFIG.39Mg—Al tailor welded blanks are shown, with a galvanically graded interface, made by slitting and rolling tubes. In accordance with example implementations, rolling of 75 mil thick ZK60 tubes down to 3 mil foils can be achieved using these tailor welded blanks. Referring toFIG.40, using interlocked feed material of AA7075 and AA6061, using the methods of the present disclosure, AA7075 can be butt jointed with AA6061 as shown with an abrupt (pictured) or extended transition length.

Accordingly, an extrusion process for forming extrusion of a desired composition from a feedstock is provided. The process can include providing feedstock for extrusion, and the feedstock comprising at least two different materials. The process can further include engaging the materials with one another within a feedstock container, with the engaging defining an interface between the two different materials as described herein. The process can include extruding the feedstock to form an extruded product. This extruded product can include a first portion that includes one of the two materials bound to a second portion that can include one of the other two materials.

Accordingly, the interface between the two materials can interlock the one material with the other material and the geometry of the interlock can define a ratio of the two materials where they are bound. This ratio can be manipulated through manipulating the geometry of the engagement. For example, there could be a small amount of one of the materials entering into a perimeter defined by the other of the two materials, and vice versa. In accordance with example implementations and specific examples, one of the materials can be Mg and the other can be Al. The process can also include where the one material is Mg ZK60 and the other material is Al 6061. Accordingly, there could be one material that has one grade and another that has another grade. For example, the material can be AA7075 and the other material can be AA6061. In accordance with example implementations, these billets can be part of the feedstock and the billets can be interlocked.

The extrusion feedstock materials may have a geometry that defines a ratio of the two materials when they are extruded as bound extrusions. The feedstock materials can be aligned along a longitudinal axis, and according to example implementations this can be the extrusion axis. The interlock of the billets can reside along a plane extending normally from the axis, and accordingly, the plane can intersect with both materials.

In order to improve the formability of magnesium sheet materials, the inventors believe that the grain sizes should be less than 5 microns and/or a weakened texture is desirable. It has been demonstrated that the novel Shear Assisted Processing and Extrusion (ShAPE) technology can not only attain the aforementioned microstructure but also help with the alignment of the basal planes (i.e. texture). This technology can also reduce the size and uniformly distribute the second phase particles, which are believed to impede the formability of sheets. In accordance with example implementations, extruded tubes of Mg can be slit open and rolled into the sheet. Extruded tubes of magnesium (ZK60 alloy) using the ShAPE process can be provided which can be 50 mm in diameter and 2 mm in wall thickness, or another diameter and wall thickness. These tubes can be slit open in a press and then rolled parallel to the extrusion axis, for example.

Referring next toFIG.41, in particular embodiments, Mg sheets can be provided that are not common in mass produced vehicles, for example. The production of these sheets can include the use of rolling of ShAPE produced and open extruded tubes. In accordance with example implementations, and with reference toFIG.41, an example rolling mill130is shown. In accordance with example implementations, rolling mill130can have conveyer132but have a sheet134of a first thickness and after passing through mill130, the sheet134can be a sheet136of a second thickness. In accordance with example implementations, this rolling can be cold rolling, hot rolling, or twin rolling. ShAPE extrusions such as ShAPE tubing can provide a feedstock for subsequent rolling that can provide differentiated and/or advantageous grain size, second phase size and distribution, and/or crystallographic texture when compared to conventional feedstocks for rolling.

Referring next toFIG.42, a series of depictions are shown demonstrating a ShAPE fabricated Mg ZK60 tube and the open tube thickness as well as the rolled tube rolled hot to a desired thickness. In accordance with example implementations, the rolled tube can be annealed between passes at between 420° C. and 450° C. for 5 minutes, and can be performed without a twin roll casting if desirable.

Referring next toFIGS.43A and43B, in accordance with example implementations and as described herein, these Mg billets such as the ZK60 billet can be produced about a chilled mandrel as disclosed herein, with frictional heat to produce a tube having an extrusion direction and basal planes about that extrusion direction. In accordance with example implementations, these materials can be anisotropic which can make them quite robust.

Referring next toFIG.44, a series of passes are shown from zero passes all the way to 16 passes of a Mg sheet. InFIG.45a 0.005 inch thickness sheet is shown and demonstrated the flexibility and robustness in the accompanying two figures. In accordance with example implementations and with reference toFIG.46, reduction per rolling pass has been plotted, and as can be seen, after about 5 rolling passes, the thickness remains uniform, but after 10 rolling passes, there can be a reduction in thickness of up to 60%. Such large reductions per pass are difficult to impossible to achieve with hot rolling of conventional Mg feedstocks intended for subsequent rolling operations.

In compliance with the statute, embodiments of the invention have been described in language more or less specific as to structural and methodical features. It is to be understood, however, that the entire invention is not limited to the specific features and/or embodiments shown and/or described, since the disclosed embodiments comprise forms of putting the invention into effect. The invention is, therefore, claimed in any of its forms or modifications within the proper scope of the appended claims appropriately interpreted in accordance with the doctrine of equivalents.