Patent Publication Number: US-2011073379-A1

Title: Cutting element and method of forming thereof

Description:
BACKGROUND 
     1. Field of the Disclosure 
     The following disclosure is directed to cutting elements for use in drill bits and/or milling bits, and particularly cutting elements incorporating a cutting body and a jacket. 
     2. Description of the Related Art 
     In the past, rotary drill bits have incorporated cutting elements employing superabrasive materials. Within the industry there has been widespread use of synthetic diamond cutters using polycrystalline diamond compacts, otherwise termed “PDC” cutters. Such PDC cutters may be self supported, otherwise a monolithic object made of the desired material, or incorporate a polycrystalline diamond layer or “table” on a substrate made of a hard metal material suitable for supporting the diamond layer. 
     However, PDC cutter designs continue to face obstacles. For example, mechanical strains are commonplace given the significant loading on the cutters, and as such, delamination and fracture of the cutters, particularly of the diamond table, can occur given the extreme loading and temperatures generated during drilling operations. Furthermore, failure of the cutters due to temperature concerns can go beyond the existence of simply encountering high temperatures, but the effects of heating and cooling on the cutters and the resultant failure of the cutters due to differences in thermal expansion coefficient and thermal conductivity of materials within the cutter. 
     Various configurations of cutters have been used to mitigate the effects of mechanical strain and temperature-induced wear characteristics. However, significant shortcomings are still exhibited by conventional cutters. 
     SUMMARY 
     According to one aspect, a cutting element includes a substrate having an upper surface, a rear surface spaced apart from the upper surface, and a side surface connected to the rear surface and upper surface. The cutting element further includes a superabrasive layer comprising a rear surface, an upper surface, and a side surface connected to and extending between the rear surface and upper surface, wherein the rear surface of the superabrasive layer overlies the upper surface of the substrate. A jacket can overlay the side surface of the substrate, abutting a portion of the rear surface of the superabrasive layer, wherein the jacket comprises a flange extending along a portion of the side surface of the superabrasive layer. 
     In accordance with another aspect, a cutting element includes a cutter body comprising a substrate having an upper surface, a rear surface spaced apart from the upper surface, and a side surface connected to the rear surface and upper surface. The cutting element also employs a superabrasive layer comprising a rear surface overlying the upper surface of the substrate at a substrate/superabrasive layer interface, and a jacket comprising an erosion-resistant material overlying a periphery of the substrate/superabrasive layer interface at a side surface of the substrate, wherein the jacket extends for a fraction of a total length of the cutter body. 
     In yet another aspect, a cutting element includes a substrate having an upper surface, a superabrasive layer comprising a rear surface overlying the upper surface of the substrate at a substrate/superabrasive layer interface, and a jacket overlying a periphery of the substrate/superabrasive layer interface, wherein the jacket comprises a coating including an erosion-resistant material. 
     According to still another aspect, a cutting element includes a substrate having an upper surface, a rear surface spaced apart from the upper surface, and a side surface connected to the rear surface and upper surface. The cutting element incorporates a superabrasive layer comprising a rear surface, an upper surface, and a side surface connected to and extending between the rear surface and upper surface, wherein the rear surface of the superabrasive layer overlies the upper surface of the substrate. Additionally, the cutting element includes a jacket abutting a portion of the rear surface of the superabrasive layer, wherein the jacket comprises an axially varying composition. 
     In accordance with another aspect, a cutting element includes a cutter body comprising a substrate having an upper surface, a rear surface spaced apart from the upper surface, and a side surface connected to the rear surface and upper surface. The cutting element has a superabrasive layer comprising a rear surface, an upper surface, and a side surface connected to and extending between the rear surface and upper surface, wherein the rear surface of the superabrasive layer overlies the upper surface of the substrate. Also, the cutting element includes a jacket releasably attached to the cutter body. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present disclosure may be better understood, and its numerous features and advantages made apparent to those skilled in the art by referencing the accompanying drawings. 
         FIG. 1  includes an illustration of a subterranean drilling operation. 
         FIG. 2  includes an illustration of a drill bit in accordance with an embodiment. 
         FIGS. 3A-3B  include a cross-sectional illustrations and a perspective view illustration of a cutter element in accordance with an embodiment. 
         FIGS. 4A-4D  includes cross-sectional illustrations of cutting elements in accordance with embodiments. 
         FIGS. 5A-5C  include cross-sectional illustrations of cutting elements in accordance with embodiments. 
         FIGS. 6A-6B  include cross-sectional illustrations of cutting elements in accordance with embodiments. 
         FIG. 7  includes a cross-sectional illustration of a cutting element in accordance with an embodiment. 
         FIGS. 8A-8B  include cross-sectional illustrations of cutting elements in accordance with embodiments. 
         FIGS. 9A-9E  include cross-sectional illustrations and perspective view illustrations of cutting elements in accordance with embodiments. 
         FIGS. 10A-10C  include cross-sectional illustrations of cutting elements in accordance with embodiments. 
         FIGS. 11A-11C  include cross-sectional illustrations of cutting elements in accordance with embodiments. 
     
    
    
     The use of the same reference symbols in different drawings indicates similar or identical items. 
     DETAILED DESCRIPTION 
     The following is directed to earth boring drilling bits and/or milling bits, and more particularly, cutting elements used in such bits. The following describes cutting elements and methods of forming such elements such that they may be incorporated within drilling and/or milling bits. The terms “bit”, “drill bit”, and “matrix drill bit” may be used in this application to refer to “rotary drag bits”, “drag bits”, “fixed cutter drill bits”, “mill- and drill-bits”, “milling bits” or any bits incorporating the teachings of the present disclosure. As will be appreciated, such drill bits may be used to form well bores or boreholes in subterranean formations as well as mill through casings or other objects within a borehole. 
     An example of a drilling system for drilling such well bores in earth formations is illustrated in  FIG. 1 . In particular,  FIG. 1  illustrates a drilling system including a drilling rig  101  at the surface, serving as a station for workers to operate a drill string  103 . The drill string  103  defines a well bore  105  extending into the earth and can include a series of drill pipes  100  and  103  that are coupled together via joints  104  facilitating extension of the drill string  103  for depths into the well bore  105 . The drill string  103  may include additional components, such as tool joints, a kelly, kelly cocks, a kelly saver sub, blowout preventers, safety valves, and other components known in the art. 
     Moreover, the drill string can be coupled to a bottom hole assembly  107  (BHA) including a drill bit  109  used to penetrate earth formations and extend the depth of the well bore  105 . The BHA  107  may further include one or more drill collars, stabilizers, a downhole motor, MWD tools, LWD tools, jars, accelerators, push and pull directional drilling tools, point stab tools, shock absorbers, bent subs, pup joints, reamers, valves, and other components. A fluid reservoir  111  is also present at the surface that holds an amount of liquid that can be delivered to the drill string  103 , and particularly the drill bit  109 , via pipes  113 , to facilitate the drilling procedure. 
       FIG. 2  includes a perspective view of a fixed cutter drill bit according to an embodiment. The fixed cutter drill bit  200  has a bit body  213  that can be connected to a shank portion  214  via a weld. The shank portion  214  includes a threaded portion  215  for connection of the drill bit  200  to other components of the BHA. The drill bit body  213  can further include a breaker slot  221  extending laterally along the circumference of the drill bit body  213  to aid coupling and decoupling of the drill bit  200  to other components. 
     The drill bit  200  includes a crown portion  222  coupled to the drill bit body  213 . As will be appreciated, the crown portion  222  can be integrally formed with the drill bit body  213  such that they are a single, monolithic piece. The crown portion  222  can include gage pads  224  situated along the sides of protrusions or blades  217  that extend radially from the crown portion  222 . Each of the blades  217  extend from the crown portion  222  and include a plurality of cutting elements  219  bonded to the blades  217  for cutting, scraping, and shearing through earth formations when the drill bit  200  is rotated during drilling. The cutting elements  219  may be polycrystalline diamond compacts (PDC) or any of the cutting elements described herein. Coatings or hardfacings may be applied to other portions of the bit body  213  or crown portion  222  to reduce wear and increase the life of the drill bit  200 . 
     The crown portion  222  can further include junk slots  227  or channels formed between the blades  217  that facilitate fluid flow and removal of cuttings and debris from the well bore. Notably, the junk slots  227  can further include openings  223  for passages extending through the interior of the crown portion  222  and bit body  213  for communication of drilling fluid through the drill bit  200 . The openings  223  can be positioned at exterior surfaces of the crown portion  222  at various angles for dynamic fluid flow conditions and effective removal of debris from the cutting region during drilling. 
       FIGS. 3A-3B  include a cross-sectional illustration and a perspective view illustration of a cutting element in accordance with an embodiment. In particular,  FIG. 3A  includes a cross-sectional illustration of a cutting element  300  employing a cutter body  350  and a jacket  303  extending around a portion of the cutter body  350  in accordance with an embodiment. The cutter body  350  can include a substrate  301  having an upper surface  307  extending transversely to the longitudinal axis  308 , a rear surface  396  parallel to the upper surface  307  and extending transversely to the longitudinal axis  308 , and a side surface  305  extending between the upper surface  307  and rear surface  396  and extending parallel to the longitudinal axis  308 . The substrate  301  can provide support for forming a superabrasive layer  302  thereon. 
     In reference to the substrate  301 , the substrate can be made of a material suitable for withstanding drilling applications. For example, the substrate  301  can employ a material having a Mohs hardness of at least about 8, or at least about 8.5, at least about 9.0, or even at least about 9.5. The substrate  301  can be formed of a carbide, nitride, oxide, boride, carbon-based material, and a combination thereof. Particular metals or metal alloy materials may be incorporated in the substrate  301 , such that the substrate can be made of a cermet. In some instances, the substrate  301  can be made of a cemented material, such as a cemented carbide. Some suitable cemented carbides can include metal carbides, and particularly cemented tungsten carbide. According to one embodiment, the substrate  301  consists essentially of tungsten carbide. 
     The substrate  301  can have a shape comprising an elongated portion defining a length extending along a longitudinal axis  308 . In certain designs, the side surface  305  of the substrate  301  can have an arcuate shape defining a circumference extending at a radius around the longitudinal axis  308 . For instance, the substrate  301  may have a cylindrical shape (e.g., a right cylinder), such that it has a circular cross-sectional contour as viewed in cross-section to the longitudinal axis  308 . It will be appreciated that alternative shapes for the substrate  301  and cutting elements herein are possible, including polygonal cross-sectional contours (e.g., rectangular, trapezoidal, pentagonal, triangular, etc.), elliptical cross-sectional contours, hemispherical cross-sectional contours, and the like. Accordingly, it will be further appreciated that reference herein to a circumference with regard to the cutting element or any of its components is reference to a dimension extending around the periphery of the identified article. As such, for designs of cutters having non-circular cross-sectional contours, reference to a circumference herein will be understood to be a reference to a dimension of the periphery. 
     According to certain embodiments, the substrate  301  can be formed to have a chamfered surface  322  that can extend between the rear surface  396  and the side surface  305  of the substrate  301 . The chamfered surface  322  can extend at an angle to the longitudinal axis  308  and can have various lengths and angles. 
     The cutter body  350  can include a superabrasive layer  302  overlying the upper surface  307  of the substrate  301 . In particular, the superabrasive layer  302  can be in direct contact with (i.e., abutting) the upper surface  307 , and more particularly, bonded directly to the upper surface  307  of the substrate  301 . In certain designs, the superabrasive layer  302  can be formed such that it has a rear surface  316  forming an interface with the upper surface  307  of the substrate  301  extending transversely to the longitudinal axis  308 . The superabrasive layer  302  can have an upper surface  309  parallel to the rear surface  316  that extends transversely to the longitudinal axis  308 . A side surface  306  of the substrate can extend between the rear surface  316  and upper surface  309  parallel to the longitudinal axis  308  of the cutter body  350 . 
     The superabrasive layer  302  can include superabrasive materials such as diamond, boron nitride (e.g, cubic boron nitride), certain carbon-based materials, and a combination thereof. The superabrasive layer can include a polycrystalline material. In fact, according to certain designs, the superabrasive layer  302  can consist essentially of polycrystalline diamond. With reference to those embodiments using polycrystalline diamond, the superabrasive layer  302  can be made of various types of diamond including thermally-stable polycrystalline diamond, which generally contain a lesser amount of catalyst material (e.g., cobalt) than other diamond materials, making the material stable at higher temperatures. In other applications, the superabrasive layer  302  can be formed such that it consists essentially of polycrystalline cubic boron nitride. 
     In some embodiments, the superabrasive layer  302  has a thickness  332  (t sal ) measured in a direction substantially parallel to the longitudinal axis  308  of the cutter body  350 . The superabrasive layer  302  can have a volume and average thickness  332  (t sal ) suitable for operating in combination with other components (e.g., a jacket  303 ) for improved performance. Generally, the superabrasive layer can have a thickness  332  (t sal ) of at least about 0.5 mm, such as at least about 1 mm, at least about 2 mm, at least about 3 mm or even at least about 4 mm. In certain exemplary designs, the superabrasive layer has a thickness within a range between about 0.5 mm and about 5 mm. 
     The superabrasive layer  302  can employ a chamfered surface  345  abutting the upper surface  309 . The chamfered surface  345  can improve the cutting performance of the cutting element  300 . In particular, the chamfered surface  345  can extend between the upper surface  309  and side surface  306  of the superabrasive layer  302 . As illustrated, the chamfered surface  345  can extend at an angle to the upper surface  309  and the side surface  306 , and more particularly, at an angle to the longitudinal axis  308  of the cutter body  350 . Various angles and lengths may be employed on the chamfered surface  345  depending upon the intended application. As will be appreciated, the chamfered surface  345  may extend around the entire periphery of the superabrasive layer  302 , such that it is in the shape of an annulus. 
     Still, in certain designs, the chamfered surface  345  may be segmented, such that it is made of discrete portions, wherein each portion extends for a distance less than the entire periphery (i.e., less than 360°) around the cutter body  350 . Moreover, in certain instances, it may be desirable to use a radiused edge as opposed to a chamfered surface. A radiused edge can have a curvature or arcuate shape that can define a radius. As such, it will be appreciated that references herein to chamfered surfaces will be understood to also include radiused edge configurations. Furthermore, it will be appreciated that the chamfered surface can be made of multiple surfaces, such that the chamfered surface comprises at least two or more surfaces, which can be angled relative to each other and the other surfaces of the superabrasive layer  302 . 
     As further illustrated in  FIG. 3A , the cutting element  300  can include a jacket  303  extending around a portion of the side surface  306  of the superabrasive layer  302  and the side surface  305  of the substrate  301 . As illustrated, the jacket  303  comprises an inner surface  310 , which can extend substantially parallel to the longitudinal axis  308 , and an outer surface  311 , opposite the inner surface  310 , which can extend substantially parallel to the longitudinal axis  308 . Additionally, the jacket  303  can have an upper surface  346  and a rear surface  314 , each of which can extend between the inner surface  310  and outer surface  311 , parallel to each other and in a direction substantially perpendicular to the longitudinal axis  308  of the cutter body  350 . 
     As further illustrated, the jacket  303  can be formed to have a chamfered surface  347  that can extend between the upper surface  346  and the outer surface  311 . The chamfered surface  347  can improve the cutting behavior, abrasion resistance, and erosion resistance of the cutting element  300 . The chamfered surface  347  can extend at an angle to the upper surface  346 , the outer surface  311  and the longitudinal axis  308  of the cutter body  350 . 
     The jacket  303  can be formed to include a chamfered surface  323  at the rear of the cutter body  350 . The chamfered surface  323  can provide coverage of the chamfered surface  322  of the substrate  301  to improve erosion resistance. In particular embodiments, the chamfered surface  323  can extend between the rear surface  314  and the outer surface  311  of the jacket  303 , and more particularly, at an angle to the rear surface  314 , outer surface  311 , and longitudinal axis  308  of the cutter body  350 . 
     The jacket  303  can be formed such that it extends peripherally (e.g., circumferentially) along the side surface  306  of the superabrasive layer  302  and the side surface  305  of the substrate  301 . The amount of peripheral coverage of the jacket can be measured in degrees of coverage based on a central angle measured perpendicular to the longitudinal axis  308  and centered at the center of the cutter body  350  defined by the longitudinal axis  308 . According to some designs, the jacket can extend through the entire periphery (i.e., 360° of coverage) of the cutter body  350 . That is, the jacket  303  is a single, monolithic piece extending around the entire circumference of the side surface  306  of the superabrasive layer  302  and the side surface  305  of the substrate  301 . 
     Alternatively, some cutting elements can incorporate a jacket  303  formed of discrete jacket portions, wherein each discrete jacket portion extends through a fraction of the total peripheral distance of the cutter body  350 . For example, a jacket portion can extend through not greater than 270°, such as not greater than 180°, such as not greater than 90°, or even not greater than 45° of the total peripheral distance of the cutter body  350 . The discrete jacket portions can be mechanically attached to each other, such as in an interlocking arrangement, through overlapping lips, grooved connections, and the like. In other designs, the discrete jacket portions may be bonded to each other, such as through the use of a brazing composition. 
     The inner surface  310  defines a central opening wherein the cutter body  350  can be disposed. In particular, the jacket  303  can be formed such that the inner surface  310  is in direct contact (i.e., abutting) with the side surface  306  of the superabrasive layer  302 . In particular designs, the jacket  303  is formed such that the inner surface  310  is directly bonded to the side surface  306  of the superabrasive layer  302 . Likewise, the jacket  303  can be formed such that the inner surface  310  is directly contacting the side surface  305  of the substrate  301 , and in particular, can be directly bonded to the side surface  305  of the substrate  301 . Direct bonding between the jacket  303  and the side surface  305  of the substrate  301  may be achieved using a single-step forming process, such as an HPHT process, which is provided in more detail herein. 
     The jacket  303  can extend along certain portions of the length (i.e., measured parallel to the longitudinal axis  308 ) of the cutter body  350 . For example, the jacket  303  can extend along at least 50% of the entire length of the cutter body  350  from the rear surface  396  of the substrate  301  to the upper surface  309  of the superabrasive layer  302 . In other embodiments, the jacket  303  is designed to extend over a greater portion of the total length of the cutter body  350 , such as at least about 60%, at least about 75%, at least about 80%, and even at least about 90%. According to one particular embodiment, the jacket  303  is formed to extend substantially along the entire length of the cutter body  350 , wherein the front surface  346  of the jacket  303  terminates at the edge between the chamfered surface  345  and the side surface  306  of the superabrasive layer  302 . It will be appreciated that certain embodiments may utilize a jacket  303  extending for a fraction of the full length of the substrate  301  along the longitudinal axis  308 , which can refer to a collar as described in more detail herein. 
     In particular designs, the jacket  303  can be formed to have a flange  348  that extends along a portion of the superabrasive layer  302 . That is, the flange  348  can extend along and overlie at least a portion of the side surface  306  of the superabrasive layer  302 . In particular, the flange  348  can have an inner surface  318  that extends along the side surface  306  in the direction of the longitudinal axis  308 , and therein overlies the side surface  306 . Notably, the inner surface  318  can be abutting the side surface  306  of the superabrasive layer  302 . The inner surface  318  of the flange  348  can extend for a fraction of the entire thickness (as measured in the same direction as the thickness  332 ) of the side surface  306 . In still other designs, the inner surface  318  of the flange  348  can extend for the entire thickness of the side surface  306  as measured between the rear surface  316  and the edge of the chamfered surface  345  joined to the side surface  306 . 
     Additionally, the jacket  303  can be formed such that at least a portion of the jacket  303  can be abutting the rear surface  316  of the superabrasive layer  302 . In some designs, such as illustrated in  FIG. 3A , the jacket  303  can be formed to have a surface  313  that is abutting a portion of the rear surface  316  of the superabrasive layer  302 . Notably, the surface  313  of the jacket  303  can extend at an angle to the longitudinal axis  308 , such as a substantially perpendicular to the longitudinal axis  308 , such that it complements the contours of the portion of the rear surface  316  of the superabrasive layer  302  that the surface  313  abuts. Moreover, the surface  313  can be bonded to the rear surface  316  of the superabrasive layer  302 . 
     In accordance with embodiments herein, the cutting element  300  is formed such that the jacket  303  can exert a radially compressive force and an axial force on the superabrasive layer  302 . Accordingly, the forces exerted by the jacket  303  on the superabrasive layer  302  are provided in a manner such that a significant portion of the force, or even a majority of the force, or even entirely all of the force applied by the jacket  303  is a radially compressive force acting in a direction substantially perpendicular to the longitudinal axis  308  of the cutter body  350  at the side surface  306  of the superabrasive layer  302 . Such forces can improve the cutting capabilities of the cutting element  300 . 
     The jacket  303  can be formed such that is has an average thickness  333  (t s ) as measured in a direction perpendicular to the longitudinal axis  308  between the inner surface  310  and the outer surface  311  of the jacket  303  that is not greater than about 5 mm. According to other embodiments, the jacket  303  can have an average thickness  333  (t s ) that is at least about 0.1 mm, such as at least about 0.5 mm, at least about 1 mm, at least about 2 mm, or even at least about 3 mm. Still, certain embodiments utilize a jacket  303  having an average thickness  333  (t s ) that is not greater than about 5 mm, on the order of not greater than about 4 mm, such that it is not greater than about 3 mm, or even not greater than about 2 mm. More particular designs may utilize an average jacket thickness  333  (t s ) within a range between about 0.1 mm and about 5 mm, such as between about 1 mm and about 4 mm, such as between about 1 mm and about 3 mm, or even between about 2 mm and about 3 mm. 
     Moreover, the flange  348  of the jacket  303  can be formed such that it has an average thickness  336  (t jf ) as measured between the surface  318  of the jacket  303  and the outer surface  311  of the jacket in a direction perpendicular to the longitudinal axis  308 . Notably, the average thickness  336  of the flange  348  can be different than the average thickness  333  of the jacket  303  at a position along the jacket  303  overlying the substrate  301 . In particular, the average thickness  336  of the flange  348  can be less than the average thickness of the jacket  303  at a position overlying the substrate  301 . 
     The cutting element  350  including the jacket  303  may be formed to have a particular outer diameter  334  (OD s ). In particular embodiments, the jacket  303  can be formed to have an outer diameter  334  (OD s ) within a range between 8 mm to about 40 mm, or even between about 8 mm and about 30 mm. 
     Certain cutting elements utilize a jacket  303  that can include erosion-resistant materials, corrosion-resistant materials, and a combination thereof. The jacket  303  can be formed of a material including an inorganic material, organic material, and a combination thereof. The material of the jacket  303  can be a polycrystalline material, an amorphous material, and a combination thereof. The jacket  303  can be made of certain inorganic materials, such as a ceramic, cermet, metal or metal alloy material. Some suitable metal or metal alloy materials can include transition metal elements. Examples, of some suitable metal elements for use in the jacket  303  can include titanium, chromium, nickel, tungsten, cobalt, iron, molybdenum, vanadium, and a combination thereof. 
     In certain embodiments, it may be suitable to form a jacket  303  comprising a super-alloy material, which is a metal or metal alloy having superior hardness and refractoriness, and which typically incorporates metal elements such as tungsten, chromium, cobalt, iron, and nickel. Some such suitable super-alloys can include nickel-based materials, cobalt-based materials, chromium-based material, and/or cobalt-chromium-based materials. In fact, super-alloy compositions include a majority amount of nickel, chromium, and/or cobalt (depending upon the precise composition) and may further include minor amounts of other alloying metal elements, such as molybdenum, tungsten, iron, and manganese. Some minor amounts of elements such as silicon and carbon may also be present. Examples of such materials include Stellite®, Inconel®, Hastelloy® and Talonite®. 
     The jacket  303  can be made of a corrosion-resistant material that can include any of the materials noted herein. In particular instances, the jacket  303  can incorporate a plug  392  made of a material suitable for use as a galvanic corrosion inhibitor. In certain designs, the plug  392  can be contained within the body of the jacket  303  and intersecting the surface  311  of the jacket  303  such that the plug can be exposed to the downhole environment and act as a galvanic corrosion inhibitor to reduce the potential corrosion to other portions of the cutting element  300 . Some suitable materials can include a metal or metal alloy, such as zinc or zinc-based material. 
     Notably, the plug  392  can be positioned within the jacket  303  such that it can be exposed to the downhole environment. Other embodiments may use a plug  392  contained within the jacket  303  and substrate  301 . It will be appreciated that the plug  392  can be placed in a position that maintains a sufficient electrical contact with the environment and maintain a suitable electrical conductivity to act as a galvanic corrosion inhibitor. In fact, while  FIG. 3A  has illustrated the plug  392  as a monolithic piece of material within the jacket  303 , other embodiments can employ different forms of the plug  392 . For example, certain embodiments can utilize a layer of the galvanic corrosion inhibiting material (e.g., a coating) overlying a portion of the jacket  303 . More particularly, the entire exterior surface of the jacket  303  can be coated by the galvanic corrosion inhibiting material. In yet other designs, the galvanic corrosion inhibiting material can be in the form of a particulate material, which can be uniformly dispersed in the material of the jacket  303 . The particulate material can be uniformly dispersed throughout the entire volume of the jacket  303 . In certain embodiments, the particulate material can be selectively deposited in regions of the jacket  303 , for example, in regions of the jacket spaced away from the interface between the superabrasive layer  302  and the substrate  301 . 
     Additionally, the jacket  303  can be made of a material such as a carbide, nitride, boride, oxide, carbon-based material, and a combination thereof. In accordance with one particular embodiment, the jacket  303  can be a cermet material. Particular examples of suitable cermet materials include tungsten carbide material or cemented tungsten carbide. 
     According to certain other designs, the cutting element  300  can be formed such that the jacket  303  comprises a polycrystalline material. The polycrystalline material can be an elemental composition, ceramic, a cermet, a metal, a metal alloy, and a combination thereof. For example, the jacket  303  can be made of a material including polycrystalline diamond. In particular instances, the jacket  303  can be formed entirely of polycrystalline diamond. In another embodiment, the jacket  303  can be formed entirely of cubic boron nitride. Yet, other designs may utilize a jacket  303  wherein a portion of the jacket  303  comprises polycrystalline diamond, such as in the form of an exterior layer, film, or series of layers. 
     In still other designs, the cutting element  300  can be formed such that the jacket  303  is made of a material including an organic material. Some suitable organic materials can include thermoset, thermoplastics, elastomers, and a combination thereof. For example, the jacket  303  can include a polymer material such as polyamides, polyimides, polyesters, polyethers, polyurethanes, gels, polyxylylenes, silicone, fluoropolymers, and a combination thereof. 
     Still, in certain embodiments, the jacket  303  and substrate  301  may be formed such that they comprise the same general composition, yet the concentration of certain species may differ between the jacket  303  and the substrate  301 . For example, the jacket  305  and substrate  301  can be made of a carbide material, specifically tungsten carbide, and yet the jacket  305  may be formed of a carbide having a different composition than that of the substrate  301 . That is, the jacket  305  can be formed such that it contains a different element, such as a different metal species, particularly a different content of a catalyst metal species (e.g., cobalt) as compared to the composition of the substrate  301 . 
     Referring to  FIG. 3B , a general perspective illustration of the cutting element of  FIG. 3A  is provided with a cut-out portion for an internal view of components of the cutting element.  FIG. 3B  does not show the particular chamfered edges and is provided to generally illustrate the orientation of the components of the cutting element  300  with respect to each other, including a cut-out portion for a clearer understanding of the orientation of the substrate  301  and the superabrasive layer  302 . As illustrated, the jacket  303  can surround the cutter body  350  including the substrate  301  and at least a portion of the side surface  306  of the superabrasive layer  302 . As described herein, and as will be appreciated, while  FIG. 3B  illustrates a cutting element  300  having a generally cylindrical shape, other polygonal shapes are contemplated, such as elliptical, triangular, rectangular, trapezoidal, hexagonal, irregular, and the like. 
       FIG. 4A  includes a cross-sectional illustration of a cutting element in accordance with an embodiment. The cutting element  400  includes components described herein, particularly including a cutter body  450  comprising a substrate  301  and a superabrasive layer  302  overlying an upper surface  307  of the substrate  301 . The cutting element  400  further includes a jacket  303  extending over the side surface  306  of the superabrasive layer  302  and the side surface  305  of the substrate  301 . Notably, the upper surface  307  of the substrate  301  is formed to have a contoured region  401 . The contoured region  401  can be formed in the upper surface  307  of the substrate  301  to aid reduction of stresses in the superabrasive layer  302 . The contoured region  401  can be formed such that it includes a protrusion  402  extending axially along the longitudinal axis  308  and displaced at a position along the longitudinal axis  308  that is different than other points along the upper surface  307 . It will be appreciated, that the contoured region  401  is illustrated as including a protrusion  402 , but other shapes and contours may be used. For example, a series of protrusions or series of grooves may be utilized, and moreover may be patterned of shapes may be utilized on the upper surface  307 , such as an arrangement of protrusions appearing as spokes extending radially along the upper surface  307  of the substrate  301  from the center of the upper surface  307  to the side surface  306  of the substrate  301 . 
     Additionally, the cutting element  400  can include a coating  411  overlying a portion of the substrate  301 . As illustrated, and according to certain designs, the coating  411  can overlie the outer surface  311  of the jacket  303 , and more particularly, can be abutting the outer surface  311  of the jacket  303 . In fact, the coating  411  can include a film that overlies all the external surfaces of the jacket  303 , including a surface portion  415  overlying the front surface  346  of the jacket  303 , a surface portion  414  overlying the chamfered surface  347  of the jacket  303 , a surface portion  413  overlying the outer surface  311  of the jacket  303 , and even a surface portion  417  overlying the chamfered surface  323  of the jacket  303 . The coating  411  can provide additional corrosion resistance and erosion resistance to the jacket  303 . 
     Suitable materials for use in the coating  411  can include inorganic materials, organic materials, and a combination thereof. Notably, the coating  411  can include the same materials of the jacket  303 . For instance, the coating  411  can be formed of an inorganic material such a as a ceramic, cermet, metal, metal alloy and a combination thereof. In particular embodiments, the coating  411  can employ a super-alloy material. 
     In still other instances, the coating  411  can be formed of a ceramic material, such as an oxide, carbide, nitride, boride, and a combination thereof. Some designs may incorporate an abrasive material in the coating  411 . Some such suitable abrasive materials can include superabrasive materials, like cubic boron nitride, diamond, and a combination thereof. In at least one embodiment, the coating  411  can be formed entirely of cubic boron nitride. In another embodiment, the coating  411  can be formed entirely of polycrystalline diamond. 
     While the coating  411  is illustrated as a layer overlying the entire external surfaces of the jacket  303 , certain designs can utilize a coating  411  that overlies only a fraction of the total external surface of the jacket  303 . For example, the coating  411  can be formed such that it overlies the external surfaces of the jacket  303  proximate to the front of the cutting element  400 , and particularly the surfaces closes to the superabrasive layer  302 , which are configured to be engaged in the cutting process. The coating  411  can selectively overlay particular portions of the jacket, including for example, the upper surface  346  of the jacket, the chamfered surface  347  of the jacket, at least a fraction of the outer surface  311  of the jacket  303 , at least a fraction of the inner surface  310  of the jacket  303 , and a combination thereof. In particular instances, the coating  411  can overlie, and in particular, can abut the inner surface  310  of the jacket  303 , such that the coating  411  is disposed between the substrate  301  and the jacket  303 . Such embodiments may be particularly useful in the context of releasable jackets  303 , which can be removed from the substrate  301 . 
       FIG. 4B  includes a cross-sectional illustration of a cutting element in accordance with an embodiment. The cutting element  420  includes components described herein, particularly including a cutter body  450  comprising a substrate  301  and a superabrasive layer  302  overlying an upper surface  307  of the substrate  301 . The cutting element  420  further includes a jacket  303  extending over the side surface  306  of the superabrasive layer  302  and the side surface  305  of the substrate  301 . Notably, the upper surface  307  of the substrate  301  is formed to have a contoured region  421  having a different contour than the embodiment of  FIG. 4A . In fact, the upper surface  307  of the substrate  301  can be contoured to have protrusions  422 ,  423 , and  424 , which can extend into complementary grooves within the superabrasive layer  302 . The protrusions  422 - 424  can extend through a circumference (or other peripheral measurement) and define a series of arcs within the upper surface  307  of the substrate  301  to reduce mechanical strains on the superabrasive layer  302  during formation and use. 
       FIGS. 4C and 4D  include cross-sectional illustrations of cutting elements according to embodiments. The cutting element  470  of  FIG. 4C  includes components described herein, particularly including a cutter body  450  comprising a substrate  301  and a superabrasive layer  302  overlying an upper surface  307  of the substrate  301 . The cutting element  470  further includes a jacket  303  extending over the side surface  306  of the superabrasive layer  302  and the side surface  305  of the substrate  301 . Notably, the jacket  303  is formed to overlay at least a portion of the rear surface  396  of the substrate  301 . According to certain embodiments, the jacket  303  can encapsulate a majority of the external surfaces (e.g., side surface  305  and rear surface  396 ) of the substrate  301 . In certain embodiments, as illustrated in  FIG. 4C , a portion of the jacket  303  is configured to extend over, and abut, a portion of the rear surface  396  of the substrate  301 . Such a configuration can facilitate improved corrosion-resistance and/or erosion-resistance of the cutting element  470  in downhole applications. 
       FIG. 4D  includes a cross-sectional illustration of a cutting element  480  similar to that of  FIG. 4C , with the distinction that the jacket  303  is overlying the entire rear surface  396  of the substrate  301 . As such, it is contemplated that embodiments herein can utilize a jacket  303  having various configurations of coverage of the substrate  301  to provide improved corrosion-resistance and/or erosion resistance. 
       FIGS. 5A-5C  include cross-sectional illustrations of cutting elements according to embodiments, In particular, the  FIGS. 5A-5C  include illustrations of embodiments using a jacket having a variable thickness that can have a changing thickness with a change in position in an axial direction, a change in position in a radial direction, or a combination of such directions. The thickness of the jacket can be a gradual variation (e.g., a tapered form), an abrupt variation (e.g., a stepped configuration), a series of discrete, abrupt variations, or a combination thereof. The thickness of the jacket can be varied such that the change in thickness is asymmetric. The asymmetry can be based around the longitudinal axis, a radial axis, or a combination thereof. For example, the inner and outer surfaces of the jacket can be varied such that the change in thickness is asymmetric with regard to the contours of the inner and outer surfaces. 
       FIG. 5A  includes a cross-sectional illustration of a cutting element in accordance with an embodiment. The cutting element  500  includes a cutter body  550  employing a substrate  301  having a superabrasive layer  302  overlying the upper surface  307  of the substrate  301 . The cutting element  500  further includes a jacket  503  overlying a side surface  306  of the superabrasive layer  302  and a side surface  305  of the substrate  301 . Generally, cutting elements of any of the embodiments herein can be formed such that the jacket can have a thickness as measured between the inner surface  510  and the outer surface  311  that varies. That is, the thickness of the jacket  503  can vary in an axial direction, a radial direction, or a combination thereof. 
     As illustrated in  FIG. 5A , the jacket  503  is formed such that its thickness varies axially, changing in thickness at different positions along the longitudinal axis  308  of the cutter body  550 . In particular embodiments, the jacket  503  can have a tapered shape, such that the thickness of the jacket  503  within the region  504  adjacent to the superabrasive layer  302  has a lesser thickness than the thickness of the jacket within region  505  adjacent to the rear surface  396  of the substrate  301 . The tapered shape of the jacket  503  can be achieved by utilizing an outer surface  311  that extends substantially parallel to the longitudinal axis and an inner surface  510  that extends at an angle to the longitudinal axis  308 . The side surface  305  of the substrate  301  can complement the inner surface  510  of the jacket  503  and extend at an angle to the longitudinal axis  308 . Thus, in certain embodiments utilizing a jacket  503  having a tapered shape, the side surface  305  of the substrate can be tapered, such that the shape of the substrate  301  can have an axially varying thickness, and in particular, can have a frustoconical shape. 
     The cutting element  500  can be formed in a one-piece construction or a two-piece construction, which will be described in more detail herein. The axially varying thickness of the jacket  503  can facilitate an improved bond between the substrate  301  and the jacket  503 , particularly when the jacket  503  is affixed to the substrate  301  of the cutting element, which is indicative of a two-piece construction. 
       FIG. 5B  includes a cross-sectional illustration of a cutting element in accordance with an embodiment. The cutting element  520  includes a cutter body  550  employing a substrate  301  having a superabrasive layer  302  overlying the upper surface  307  of the substrate  301 . The cutting element  520  includes a jacket  523  overlying the side surface  306  of the superabrasive layer  302  and the side surface  305  of the substrate  301 . Unlike the jacket  503  of  FIG. 5A , the jacket  523  of  FIG. 5B  can have a tapered shape, wherein the thickness of the jacket  523  in the region  504  adjacent to and abutting the rear surface  316  of the superabrasive layer  302  can be greater than a thickness of the jacket  523  in the region  505  at the rear surface  525  of the jacket  523 . As illustrated, the cutting element  520  can achieve a jacket  523  having a tapered shape by utilizing an inner surface  526  that is angled relative to the longitudinal axis  308  and outer surface  311  of the jacket  523 , wherein the outer surface  311  and the longitudinal axis  308  extend along directions substantially parallel to each other. 
     It will be appreciated that the jackets of embodiments herein can also achieve an axially variable thickness by changing the contour of the outer surface  311  of the jacket. That is, the inner surface  510  can be formed such that it extends parallel to the longitudinal axis  308  of the cutter body  550 , but the outer surface  311  of the jacket  523  is angled relative to the longitudinal axis  308  of the cutter body  550 . 
       FIG. 5C  includes a cross-sectional illustration of a cutting element in accordance with an embodiment. The cutting element  560  includes a cutter body  550  employing a substrate  301  having a superabrasive layer  302  overlying the upper surface  307  of the substrate  301 . The cutting element  560  includes a jacket  563  overlying a side surface  306  of the superabrasive layer  302  and a side surface  305  of the substrate  301 . According to the embodiment of  FIG. 5C , the jacket  563  has a variable thickness that changes thickness at different axial positions along the longitudinal axis  308  at discrete intervals. As such, the jacket  563  can have an inner surface  561  comprising a plurality of discrete steps, wherein each of the steps can have a different axial and radial position relative to each other. The jacket  563  therein can have a difference in thickness at each of the discrete steps. 
     As illustrated in the embodiment of  FIG. 5C , the jacket  563  can have a greater thickness in the region  564  as compared to the thickness of the jacket  563  in the region  565 . The jacket  563  can have an inner surface  561  comprising a plurality of discrete steps, including for example a surface  566  defining a first step having a first thickness and a second surface  568  displaced axially from the surface  566  and radially displaced from the surface  566  in a position closer to the outer surface  311  of the jacket  563 . The surfaces  566  and  568  are joined by a surface  567  extending substantially perpendicular to the longitudinal axis  308  and the surfaces  566  and  568 . Such a configuration facilitates the formation of an inner surface  561  comprising the discrete steps to form the jacket  563  having an axially varying thickness along the length of the jacket  563  from the upper surface  346  to the rear surface  569 . 
     The substrate  301  can be formed, either through a direct forming process (such as casting or molding) or by machining to have a side surface  305  having a complementary contour to the inner surface  561  of the jacket  563 . That is, the substrate  301  can have a side surface  305  comprising a plurality of steps for complementary engagement with the inner surface  561  of the jacket  563 . Such a design can facilitate an interlocking relationship between the two components. 
     It will be appreciated that other embodiments can be utilized wherein the thickness of the jacket  563  varies in a different manner, for example, a jacket wherein the thickness is greater in the region  565  as compared to the thickness of the jacket in the region  564 . Moreover, it will be appreciated that while the illustrated embodiments demonstrates a symmetrical, stepped configuration for the inner surface  561  of the jacket  563 , other contours may be utilized. For example, the inner surface  561  can include steps of different radial height and/or axial length as compared to other steps along the inner surface  561 . Additionally, the cutting elements of embodiments herein can utilize a combination of features, such as a jacket having a combination of a tapered surface and stepped surface. 
       FIG. 6A  includes a cross-sectional illustration of a cutting element in accordance with an embodiment. The cutting element  600  can include a cutter body  650  employing a substrate  301  having a superabrasive layer  302  overlying the upper surface  307  of the substrate  301 . The cutting element  650  can include a jacket  603  overlying the side surface  306  of the superabrasive layer  302  and the side surface  305  of the substrate  301 . According to the embodiment of  FIG. 6A , the jacket  603  can have a flange  648  that includes an inner surface  606  that extends axially over the entire length of the side surface  306  of the superabrasive layer  302  between the rear surface  316  and the chamfered surface  345 . In such embodiments, the flange  648  is placed in a direct cutting position configured to share the cutting load with the superabrasive layer  302 . It will be appreciated, that such a configuration may be most suitable for use with a jacket comprising an abrasive material, such as a superabrasive material (e.g., polycrystalline diamond or cubic boron nitride). 
       FIG. 6B  includes a cross-sectional illustration of a cutting element in accordance with an embodiment. The cutting element  620  can include a cutter body  650  employing a substrate  301  having a superabrasive layer  302  overlying the upper surface  307  of the substrate  301 . The cutting element  650  can include a jacket  603  overlying the side surface  306  of the superabrasive layer  302  and the side surface  305  of the substrate  301 . Notably, the jacket  603  can have a particularly shaped flange  648  overlying and abutting the side surface  306  of the superabrasive layer  302 . In accordance with at least one embodiment, the flange  648  is formed to have an upper surface  607  that extends at an angle to the longitudinal axis  308 , such that it can be a tapered surface. Particularly, the upper surface  607  can be a tapered surface terminating at the edge between the side surface  306  and chamfered surface  345  of the superabrasive layer  302 . The upper surface  607  can extend at various angles and for various lengths depending upon the intended application. Moreover, it will be appreciated that the upper surface  607  can be formed with a curvilinear shape, such that the upper surface  607  can be a radiused surface in certain embodiments. 
       FIG. 7  includes a cross-sectional illustration of a cutting element in accordance with an embodiment.  FIG. 7  includes a cutting element  700  having a cutter body  750  employing a substrate  301  and a superabrasive layer  302  overlying an upper surface  307  of the substrate  301 . Additionally, the cutting element  700  includes a jacket  703  that can be abutting a surface of the superabrasive layer  302 . In particular, the superabrasive layer  302  can include a flange region  707  that extends axially along the side surface  305  of the substrate  301 . The jacket  703  can be formed to have an upper surface  719  that is flush with and directly contacting a surface of the flange region  707 . The flange region  707  can include the same materials and properties of the superabrasive layer  302  as described herein. In particular, the flange region  707  can utilize a polycrystalline diamond material, and in certain instances, can consist essentially of a polycrystalline diamond material, offering additional corrosion-resistance and/or erosion resistance. It will be appreciated, that while the jacket  703  is not illustrated as overlying a side surface of the superabrasive layer, and particularly a side surface of the flange region  707 , such embodiments are contemplated. 
     As illustrated, the flange region  707  can be formed to extend axially to a position behind rear surface  316  of the superabrasive layer, such that the surface  708  of the flange region  707  is closer to the rear surface  396  of the substrate  301  as compared to the distance between the surface  316  of the superabrasive layer  302  and the rear surface  396  of the substrate. Notably, the flange region  707  can be a portion of the superabrasive layer  302  that can extend axially along a portion of the side surface  305  of the substrate  301 . Such a design can provide additional protection from erosion and/or corrosion to the interface between the rear surface  316  of the superabrasive layer  302  and the upper surface  307  of the substrate  301 . 
     The flange region  707  can be defined by a surface  708  that extends substantially perpendicular to the longitudinal axis  308  and terminates at an upper surface  719  of the jacket  703 . Additionally, the flange region  707  can be further defined by an inner surface  711  connected to the rear surface  316  and the surface  708  in a direction substantially parallel to the longitudinal axis  308  of the cutter body  750 . The surface  711  can overlie, and in particular, can be abutting the side surface  305  of the substrate  301 . The surface  709  can further define the flange region and extend between the chamfered surface  345  and the surface  708 . 
     The flange region  707  can have a length (L f ) measured as a distance in an axial distance along the longitudinal axis  308  between a midpoint at the rear surface  316  of the superabrasive layer  302  (i.e., the intersection between the rear surface  316  of the superabrasive layer  302  and the longitudinal axis  308 ) and the rear-most point (i.e., closest to the rear surface  396  of the substrate  301 ) on the surface  708 . In certain embodiments, the flange region  707  can have a length (L f ) that is at least about 2% of the total length (L ce ) of the cutting element as defined by the equation [(L ce −L f )/L ce ]×100%, wherein L ce  is the length of the cutting element  700  and L f  is the length of the flange region  707 . According to certain other embodiments, the flange region  707  can have a length of at least about 5%, at least about 10%, or even at least about 15% based on the equation above. Yet, some embodiments can utilize a flange region  707  having a length within a range between about 2% and about 50%, such as between about 2% and about 40%, between about 5% and about 30%, between about 5% and about 20%, or even between about 10% and about 25% of the total length of the cutting element  700 . 
     The cutting element  700  can be formed as single, monolithic article in a one-step forming process (e.g., a HP/HT forming process), or alternatively, the cutting element  700  can be formed using a two-step forming process, which may employ formation of the components separately and a subsequent joining step between components. While the jacket  703  is illustrated as having a shape wherein the upper surface  719  terminates at the surface  708 , other embodiments can utilize a jacket  703  having a flange portion (as illustrated in other embodiments) that is overlying and abutting the surface  709  of the flange region  707  of the superabrasive layer  302 . 
       FIGS. 8A-8B  include cross-sectional illustrations of cutting elements in accordance with embodiments. Generally, cutting elements of embodiments herein can utilize a jacket and cutter body that may be mechanically interlocked with each other. That is, the jacket and cutter body can be formed of a single, monolithic article in a one-step forming process. In such instances, the jacket and the cutter body can be integrally bonded to each other without a noticeable seam or bond joint. In still other embodiments, the jacket and cutter body can be affixed to each other using a two-step forming process, wherein the cutter body is formed first and the jacket is formed separately and the two components are mechanically affixed to each other. In such instances, the jacket can be affixed to the cutter body using different mechanisms including a releasable mechanical connection such that many jackets can be interchanged with the cutter body, a permanent fixation using a bond joint (e.g., permanently brazed coupling assembly), fasteners, interlocking connections, interference fit connections, taper-lock connections, a combination thereof, and the like. Mechanically interlocking connections between the cutter body and the jacket can be accomplished by incorporation of interfacial surface features on the inner surface of the cutter body, particularly the substrate, and the jacket. Notably, such interfacial features can include the use of complementary engaging features that are designed to interlock the jacket and cutter body at the interface between the jacket and substrate. Some suitable examples of interfacial surface features can include grooves and/or protrusions extending axially and/or radially along the inner surface of the jacket and cutter body, honeycomb structures, threaded surfaces, and the like. 
     One such design of mechanically interlocking orientation between the components is provided in  FIG. 8A .  FIG. 8A  includes a cross-sectional illustration of a cutting element in accordance with an embodiment. The cutting element  800  includes a cutter body  850  comprising a substrate  301  and a superabrasive layer  302  overlying an upper surface  307  of the substrate  301 . A jacket  803  can extend axially over the side surface  306  of the superabrasive layer  302  and the side surface  305  of the substrate  301 . The jacket  803  and the substrate  301  can include a contoured region along their respective inner surfaces  310  and  305  for complementary engagement and mechanically interlocking the two components. Contoured regions as used herein can reference protrusions, grooves, lips, or any other surface features suitable for interlocking engagement between the jacket  803  with the substrate  301 . As illustrated in  FIG. 8A , the jacket  803  comprises a protrusion  801  extending radially inward along the inner surface  310  that is configured to be engaged with a complementary groove  805  within the side surface  305  of the substrate  301 . As will be appreciated, the protrusion  801  may extend for a portion of the peripheral (e.g. circumferential) dimension of the inner surface  310  of the jacket  803 . That is, the protrusion  801  can extend peripherally along the inner surface  310  of the jacket  803  for a distance of at least about 45°, at least about 90°, or even at least about 180°. In certain instances, the protrusion  801  may extend for the full peripheral dimension of the inner surface  310  of the jacket  803  (i.e., 360°). Likewise, the complementary groove  805  may extend for the same distance for proper complementary engagement of the groove  801  therein. 
     Notably, the protrusion  801  can be placed in an axial position along the length of the jacket  803 , such that it is proximate to the rear surface  314  of the jacket  803 . In particular, the protrusion  801  can be axially spaced apart from the rear surface  316  of the superabrasive layer  302  to avoid potential weakening of the mechanical bond between the substrate  301  and the superabrasive layer  302 . As such, embodiments herein may utilize a protrusion (and any other surface features) for complementary engagement of the substrate  301  and the jacket  803  at a position that is closer to the rear surface  396  of the substrate  301  than the rear surface  316  of the superabrasive layer  302 . 
       FIG. 8B  includes a cross-sectional illustration of a cutting element in accordance with an embodiment. The cutting element  820  includes a cutter body  850  comprising a substrate  301  and a superabrasive layer  302  overlying an upper surface  307  of the substrate  301 . A jacket  803  can extend axially over the side surface  306  of the superabrasive layer  302  and the side surface  305  of the substrate  301 . The jacket  803  and the substrate  301  can include a contoured region along their respective inner surfaces  310  and  305  for complementary engagement and mechanically interlocking the two components. As illustrated in  FIG. 8B , the jacket  803  comprises a groove  829  extending radially outward into the body of the jacket  803  to define a cavity therein. A complementary protrusion  821  extends radially outward from the side surface  305  of the substrate  301  and is configured to engage the groove  829  and mechanically interlock the substrate  301  and the jacket  803 . 
     In particular, the groove  829  can be defined by a linear surface  822  and curved surface  823 , a combination of which can aid coupling and proper placement between the substrate  301  and the jacket  803 . Such a structure of the groove  829  and the protrusion  821  can facilitate proper seating between the jacket  803  and substrate  301  for proper bonding between the two components. Alternatively, the groove  829  and protrusion  821  can be shaped such that the jacket  803  is releasably engaged with the substrate  301 , for use of interchangeable jackets. 
       FIG. 9A  includes a cross-sectional illustration of a cutting element in accordance with an embodiment. In particular,  FIG. 9A  includes a cutting element  900  having those components described in embodiments herein, including a cutter body  950  comprising a superabrasive layer  302  overlying an upper surface  307  of a substrate. The cutting element  900  further includes a jacket, which is in the form of a collar  901 , which can extend axially along the side surface  305  of the substrate  301  and along at least a portion of the side surface  306  of the superabrasive layer  302 . Notably, the collar  901  is a particular formulation of the jacket of embodiments herein, and is distinguished from other jackets because the collar  901  extends for a fraction of the total length (L ce ) of the cutting element  900 . The collar  901  can have an exterior side surface  903  that extends parallel to the side surface  305  of the substrate  301  and parallel to the longitudinal axis  308  of the cutter body  950 . The collar  901  can further include a front surface  902 , which can be a chamfered surface, extending at an angle to the longitudinal axis  308 . Additionally, the collar  901  can be defined by a rear surface  904  extending from the exterior side surface  903  and connected to the side surface  305  of the substrate  301 . The collar can have the same features and properties of the jackets described in accordance with embodiments herein, particularly with regard to the use of corrosion-resistance and/or erosion resistant materials. 
     The collar  901  can be mechanically connected to the cutter body  950 , and more particularly, mechanically connected to the substrate  901 . In certain instances, the collar  901  can be permanently mechanically connected (i.e., affixed) to the cutter body  950 . In instances wherein the collar  901  is affixed to the substrate  301 , the means for affixing the two components can include various implements, such as fasteners, interlocking connections, bonding mechanisms (e.g., brazing), a combination thereof and the like. In other designs, the collar  901  can be releasably attached to the cutter body  950 , such that after use of the cutting element  900  and sufficient wear to the collar  901 , the collar  901  can be replaced with a new collar and the cutting element may be reused. Some suitable mechanisms for implementing releasable engagement between the collar  901  and the substrate  301  can include fasteners, interlocking connections, snap-fit connections, taper-fit connections, temperature-induced fitting procedures using a temperature differential between components, bonding compounds and mechanisms (e.g., adhesives, etc) a combination thereof and the like. 
     According to the illustrated embodiment of  FIG. 9A , the collar  901  can have an engagement arm  906  that is configured to extend radially inward, into the body of the substrate  301  within a complementary groove  905  within the side surface  305  of the substrate  301 . The engagement arm  906  and groove  905  can be an interlocking connection for mechanically affixing the collar  901  to the substrate  301 . In other embodiments, the engagement arm  906  and groove  905  can be a releasable connection, such that the collar  901  can be removed from the cutter body  950 . 
     Moreover, the engagement arm  906  can be positioned such that it extends from the rear surface  904  of the collar  901 . The position of the engagement arm  906  ensures that it is engaged within the interior of the substrate at a sufficient distance from the rear surface  316  of the superabrasive layer  302  to avoid weakening the bond between the superabrasive layer  302  and the substrate  301 . 
     As further illustrated in the embodiment of  FIG. 9A , the collar  901  can have a length (L c ) as measured in an axial direction parallel to the longitudinal axis  308 . The length of the collar  901  can extend for a fraction of the entire length (L ce ) of the cutting element as defined by the equation [(L ce −L c )/L ce ]×100%, wherein L ce  is the length of the cutting element and L c  is the length of the collar  901 . Notably, independent of the length, a portion of the collar  901  can be configured to cover the interface between the superabrasive layer  302  and the substrate  301  defined by the upper surface  307  of the substrate  301  and rear surface  316  of the superabrasive layer  302 . 
       FIG. 9B  includes a perspective view of the cutting element of  FIG. 9B . As illustrated, the collar  901  can extend around the periphery of the outer side surface  305  of the substrate  301 . In particular, as illustrated, the collar  901  overlies the interface between the substrate  301  and the superabrasive layer  302  to reduce the damage to the interface due to the corrosive and erosive downhole environment. According to one particular embodiment, the collar  901  can extend around the entire periphery (i.e., circumference) of the cutter body  950 . 
       FIG. 9C  includes a cross-sectional illustration of a cutting element in accordance with an embodiment. In particular,  FIG. 9C  includes a cutting element  910  having those components described in embodiments herein, including a cutter body  950  comprising a superabrasive layer  302  overlying an upper surface  307  of a substrate. The cutting element  910 , like the cutting element  900 , includes a jacket, which is in the form of a collar  911 , which can extend axially along the side surface  305  of the substrate  301  and along at least a portion of the side surface  306  of the superabrasive layer  302 . The collar  911  of  FIG. 9C  differs from the collar  901  of  FIG. 9A  in that the collar  911  has a greater length and differently shaped engagement arm  917  extending radially inward into the body of the substrate  301 . The collar  911  can include an upper surface  912  angled relative to the longitudinal axis  308  and overlying, and particularly, abutting the side surface  306  of the superabrasive layer  302 . The collar  911  further includes an exterior side surface  913  extending between the upper surface  912  and a rear surface  914  substantially parallel to the longitudinal axis  308 . 
     The collar  911  includes an engagement arm having a particular re-entrant shape. The re-entrant shape includes surfaces  915  and  918  that can be angled relative to each other such that the surface  916  has a greater length than a length between the surfaces  918  and  915  at the side surface  305  of the substrate  301 . Given the shape of the engagement arm  917 , the collar  911  may not necessarily be removed in a direction laterally and can avoid removal during operation. The collar  911  may be engaged in the complementary groove of the substrate  301  by sliding the collar peripherally along an engagement groove within the substrate  301  until the engagement arm  917  is contained within the groove. 
     Unlike the collar  901  of  FIG. 9A , the collar  911  may not necessarily extend through the entire periphery (i.e., circumference) of the cutter body  950 .  FIG. 9D  includes a perspective view of the cutting element  910  of  FIG. 9C  as placed in the blade  922  of a drill bit. As illustrated, the cutting element  910  is configured within the surface of the drill bit, such that the collar  911  extends around the circumference of the cutter body  950  and is in a cutting position configured to potentially engage downhole formations and provide suitable corrosion-resistance and/or erosion resistance for the interface between the substrate  301  and the superabrasive layer  302 . 
       FIG. 9E  includes a cross-sectional illustration of the cutting element of  FIG. 9A  in a cutting position according to an embodiment. As illustrated, the cutting element  910  when contained within a drill bit can be angled relative to a surface  940  to remove material from the surface  940 , which is a typical configuration in a downhole material removal process. As illustrated, the collar  911  of the cutting element is configured to engage a portion of the surface  940  within the region  941  after the surface  940  is engaged by the superabrasive layer  302 . The region  941  can be an erosive and corrosive environment, which can attack the interface between the substrate  301  and the superabrasive layer  302 . The collar  911  can provide suitable protection against this environment and improve the cutting capabilities and lifetime of the cutting element  910 . 
     The cutting elements herein can have a jacket that is designed to have a different composition than the composition of the substrate. The difference in composition can be a difference in at least one element, a compound, or the entire composition. According to one embodiment, the jacket can have a composition that varies from the substrate based on the content of a single species (e.g., a catalyst material), such that the jacket and the substrate can generally have the same basic composition, yet the content of certain elements contained within the composition are varied. For example, particular embodiments can have a jacket having an average cobalt content (or any other content of a catalyst material) that is different than the average cobalt content of the substrate. In certain embodiments, the jacket can have an average cobalt content that is at least 1% less than the average cobalt content of the substrate. For example, the substrate can have an average cobalt content of 12%, and accordingly, the jacket can have an average cobalt content of 11% or less. 
     In other instances, the difference in the cobalt content between the jacket and the substrate can be greater, such that the average cobalt content of the jacket is at least about 3% less, at least about 5% less, at least about 8% less, or even at least about 10% less. In accordance with at least one embodiment, the average cobalt content of the jacket can be within a range between about 1% and about 15% less, such as between about 1% and about 12% less, or even between about 3% and about 10% less than the average cobalt content of the substrate. The foregoing has made specific reference to cobalt, however, cutting elements utilizing other catalyst materials, such as iron, nickel, and even a combination of catalyst materials, can utilize the same differences in composition between the substrate and the jacket. 
     Additionally, the cutting elements of the embodiments herein can employ a jacket having a different microstructure than the microstructure of the substrate. The microstructure can be characterized by the grade of material used, the average grain size, shape of the grains, distribution of grain sizes, and the like. According to one embodiment, the jacket is formed from a grade of tungsten carbide that is different than the grade of tungsten carbide used to form the substrate. In still other embodiments, the jacket comprises an average grain size of tungsten carbide that is different than the average grains size of the substrate. In a particular design, the jacket is formed of tungsten carbide having a smaller average grain size than the average grains size of the substrate, which may provide improved erosion-resistance. While such distinctions have mentioned the use of tungsten carbide, it will be appreciated that such distinctions in microstructure between the substrate and the jacket can be utilized for any of the materials described herein. 
     According to embodiments of certain cutting elements, the jacket can be formed from a series of films or layers of material, such that the composition of the jacket can be an axially varying composition, a radially varying composition, and a combination thereof. For example, in certain jackets having a radially varying composition, the composition of the jacket at a first radial position can be different than the composition of the jacket a second radial position. Likewise, for axially varying compositions, the composition of the jacket between a first and second position axially spaced apart from each other within the jacket can have different compositions. 
     In particular, the varying compositions can be a gradient of a composition, wherein the composition changes gradually with a change in positions along the body of the jacket. As such, in embodiments using a gradient of axially varying and/or radially varying composition, the jacket may not necessarily be formed of discrete layers or films of material. Rather, the jacket can be a monolithic article, and more particularly, the substrate and jacket can be integrally bonded to form a monolithic article, wherein the composition gradually varies in an axial and/or radial direction through the entire substrate/jacket assembly. 
     The difference in composition for such jackets can be based on a difference of the entire composition or a single chemical species (e.g., element), wherein the content (mass or volume) of the particular species within the composition changes with a change in the radial and/or axial position on the jacket. For example, in certain instances, the jacket can be formed of tungsten carbide, and the tungsten carbide composition can have a particular content of a catalyst material, such as cobalt. In particular embodiments, the cobalt composition of the jacket can vary axially or radially. That is, in one design, the jacket comprises a gradient of cobalt content along the length of the jacket body, such that the cobalt content within the jacket gradually changes along the length of the jacket, thus defining an axially varying cobalt gradient. In other embodiments, the jacket can employ a radially varying cobalt content, such that the cobalt content within the jacket gradually changes along the thickness of the jacket from the inner surface to the external side surface of the jacket. Still, it will be appreciated that a jacket body employing a number of layers, wherein the layers can have a different chemical composition with respect to each other, can include a composite arrangement, wherein for example, one layer comprises a first chemical composition (e.g., tungsten carbide) and a second layer comprises a second chemical composition (e.g., polycrystalline diamond) different than the first chemical composition. 
       FIGS. 10  A- 10 C provide cross-sectional illustrations of cutting elements employing jackets having radially varying and/or axially varying compositions.  FIG. 10A  includes a cross-sectional illustration of a cutting element according to an embodiment. The cutting element  1000  can include those components described herein, notably a cutter body  1050  including a substrate  301  and a superabrasive layer  302  overlying the upper surface  307  of the substrate  301 . The substrate  301  can further include a jacket  1003  having an inner surface  310  overlying, and in particular, abutting the side surface  305  of the substrate  301 . The jacket  1003  can further include an upper surface  1002  that is abutting the rear surface  316  of the superabrasive layer  302 . Notably, according to the illustrated embodiment, the jacket  1003  can be formed such that there may not necessarily be a flange overlying the side surface  306  of the superabrasive layer  302 , however, it will be appreciated that such configurations can be used. 
     The jacket  1003  can have a radially varying composition. As illustrated, the jacket  1003  can have layered regions  1008 ,  1009 , and  1010  that are radially spaced apart from each other and extend generally parallel to the longitudinal axis  308  of the cutter body  1050 . In certain embodiments, the layered regions  1008 - 1010  can be separated by discrete interfaces, such that the layered regions  1008  and  1009  can be separated at an interface  1012  that can extend generally parallel to the longitudinal axis  308  of the cutter body  1050 . Moreover, the layered regions  1009  and  1010  can be separated at an interface  1011  that can extend generally parallel to the longitudinal axis  308  of the cutter body  1050 . 
     Each of the layered regions  1008 - 1010  can represent regions within the jacket having compositions that can be different from each other. For example, the position  1004  within the layer  1008  is radially spaced apart from the position  1005  within the layer  1009 , and particularly, the position  1004  can have a composition that is different from the composition of the position  1005 . Moreover, the position  1005  within the layer  1009  is radially spaced apart from the position  1006  within the layer  1010 , and particularly, the position  1005  can have a composition that is different from the composition of the position  1006 . Likewise, the positions  1004  and  1006 , which are radially spaced apart from each other, can have a difference in composition. The layered region  1008 - 1010  can have compositions wherein the content of at least one species is different as compared to the content of the same species within any of the other layered regions  1008 - 1010 . Additionally, the layered regions  1008 - 1010  can have a composition, wherein at least one chemical species (e.g., a catalyst material) is present within one of the layered regions and can be absent from one of the other layered regions  1008 - 1010 . Furthermore, it will be appreciated that while the jacket  1003  is illustrated as having three layered regions, more or less layered regions can be used to construct the jacket  1003 . 
     According to one embodiment, the jacket  1003  can have a radially varying composition, such that the content of a catalyst material, such as cobalt, at the positions  1004 ,  1005 , and  1006  are different compared to each other. In fact, in certain designs, the layered region  1008  can have an average cobalt content that is greater than the average cobalt content within the layered regions  1009  and  1010 . Moreover, the layered region  1009  can have an average cobalt content that is greater than the average cobalt content within the layered region  1010 . Accordingly, the cobalt content of the composition at position  1004  can be greater than the cobalt content of the composition at positions  1005  and  1006 , and likewise, the cobalt content of the composition at position  1005  can be greater than the cobalt content of the composition at position  1006 . It will be appreciated that other catalyst materials besides cobalt can be employed, and can exhibit the features noted in the foregoing. 
     In certain embodiments, the jacket  1003  can be formed to have layered regions  1008 - 1010  wherein the compositions differ from each in a greater manner than the content of one chemical species. For example, the layered regions  1008 - 1010  can differ from each other in that one of the layered regions  1008 - 1010  can have an entirely different composition than another one of the layered regions  1008 - 1010 . In particular, the jacket  1003  can be constructed such that the layered region  1010  can include a polycrystalline material, such as polycrystalline diamond, wherein the one of the layered regions  1008  or  1009  can be formed of a completely different composition, such as tungsten carbide. 
     Moreover, it will be appreciated, that the layered regions  1008 - 1010  can have a distinction in microstructure as compared to each other. For example, the layered regions  1008 - 1010  can differ from each other on the basis of average grains size, grain size distribution, grade of material, shape of the grains, and a combination thereof. In one particular embodiment, the layered region  1010  can be formed of a material (e.g., tungsten carbide) having an average grain size that is less than the average grains size of the material, which may be the same or different, within the layered region  1009 . 
     It will be appreciated that while the jacket  1003  is illustrated as having discrete layered regions  1008 - 1010 , such radially varying composition can also be achieved through a gradient structure, which may not utilize discrete layered regions within the jacket. The difference between forming a jacket with discrete layered regions having discrete interfaces and a jacket having a gradient structure, wherein the discrete interfaces may not be identifiable, can be achieved through different forming processes, which will be described in more detail herein. 
     The layered regions  1008 - 1010  are illustrated as having substantially the same thicknesses, as measured in a direction perpendicular to the longitudinal axis between the respective interfaces separating the layered regions  1008 - 1010 . In certain instances, the layered regions  1008 - 1010  may not necessarily have the same thickness as compared to each other. Moreover, the layered regions  1008 - 1010  can have relatively parallel structures, such that they extend along the axial direction  308 , and may not necessarily define flanges or similar structures as provided in other components of the cutting element  1000 . 
     According to a particular embodiment, the jacket  1003  can include an outermost layer (e.g., layered region  1010 ) comprising a first composition, such as tungsten carbide, and the layered region  1009  abutting the outermost layer can have a second, different composition as compared to the first composition. In particular, the second composition of layered region  1009  can be a superabrasive material, such as polycrystalline diamond, cubic boron nitride, and a combination thereof. Other embodiments herein may utilize a combination of tungsten carbide overlying layers or regions of superabrasive material, such that the superabrasive layer acts to further limit effects of erosion. Such configurations of layered regions comprising alternating compositions of superabrasive material and cermet (e.g., tungsten carbide) may serve to improve the life of the cutting element and limit erosion. 
       FIG. 10B  includes a cross-sectional illustration of a cutting element according to an embodiment. The cutting element  1020  can include those components described herein, notably a cutter body  1050  including a substrate  301  and a superabrasive layer  302  overlying the upper surface  307  of the substrate  301 . The substrate  301  can further include a jacket  1023  having an inner surface  310  overlying, and in particular, abutting the side surface  305  of the substrate  301 . The jacket  1023  can further include an upper surface  1002  that is abutting the rear surface  316  of the superabrasive layer  302 . Notably, according to the illustrated embodiment, the jacket  1023  can be formed such that there may not necessarily be a flange overlying the side surface  306  of the superabrasive layer  302 , however, it will be appreciated that such configurations can be used. 
     The jacket  1023  can have an axially varying composition that can be enabled by the formation of layered regions  1027 ,  1028 , and  1029  that are axially spaced apart from each other and define distinct axial regions within the body of the jacket  1023 . According to one embodiment, each of the layered regions  1027 - 1029  can represent regions within the jacket having compositions that can be different from each other. In particular, the layered regions  1027 - 1029  can exhibit differences in the composition similar to the layered regions  1008 - 1010  of the embodiment of  FIG. 10A . Moreover, the layered regions  1027 - 1029  can have the same characteristics (e.g., differences in microstructure) as described in accordance with the embodiment of  FIG. 10A . 
     For example, the position  1024  within the layered region  1027  is axially spaced apart from the position  1025  within the layered region  1028 , and particularly, the position  1024  can have a composition that is different from the composition of the position  1025 . Moreover, the position  1025  within the layered region  1028  is axially spaced apart from the position  1026  within the layered region  1029 , and particularly, the position  1025  can have a composition that is different from the composition of the position  1026 . Likewise, the positions  1024  and  1026 , which are axially spaced apart from each other, can have a difference in composition. The layered regions  1027 - 1029  can have compositions wherein the content of at least one species is different as compared to the content of the same species within any of the other layered regions  1027 - 1029 . Additionally, the layered regions  1027 - 1029  can have a composition, wherein at least one chemical species is present within one of the layered regions and can be absent from one of the other layered regions  1027 - 1029 . Furthermore, it will be appreciated that while the jacket  1023  is illustrated as having three layered regions, more or less layered regions can be used to construct the jacket  1023 . 
     As illustrated, the jacket  1023  can have layered regions  1027 - 1029  that are axially spaced apart from each other and can be separated by discrete interfaces, such that the layered regions  1027  and  1028  can be separated at an interface  1021  that can extend generally perpendicular to the longitudinal axis  308  of the cutter body  1050 . Moreover, the layered regions  1028  and  1029  can be separated at an interface  1022  that can extend generally perpendicular to the longitudinal axis  308  of the cutter body  1050 . 
     Notably, the layered regions  1027 - 1029  can have a difference in chemical composition as compared to each other. For example, according to one embodiment, the composition within the layered region  1027  can have an average cobalt content that is significantly different than the average cobalt content of the composition within the layered region  1028  and/or  1029 . In one particular embodiment, the jacket  1023  comprises an axially varying cobalt composition, wherein the average cobalt content decreases as axial position changes moving in a direction parallel to the longitudinal axis  308  from the rear surface  314  to the upper surface  1002  through the body of the jacket  1023 . As such, the composition at position  1024  can have a cobalt content that is less than the cobalt content of the composition at position  1025  and/or position  1026 . 
     According to an alternative embodiment, the layered region  1027  can be segmented axially, such that it includes an upper region defining the exterior surface of the jacket  1032  and extending for approximately half of the thickness radially into the interior of the jacket  1032 . The layered region  1027  can further include a lower region abutting the substrate  301  and defining an interior surface of the jacket  1032  and abutting the upper region. Accordingly, the layered region  1027  can be segmented into two distinct regions; and upper region and a lower region. The upper region can include a material such as tungsten carbide as noted herein. In contrast, the lower region can include a different material, such as a polycrystalline superabrasive material, and particularly, polycrystalline diamond or cubic boron nitride. The lower region can facilitate limited erosion of the article, particularly behind the superabrasive layer  302 . It will be appreciated that the layered region  1027  can be segmented into further layers or have a gradient structure as described herein. Additionally, any of the layered regions  1028  and  1029  can have the same features. 
       FIG. 10C  includes a cross-sectional illustration of a cutting element according to an embodiment. The cutting element  1040  can include those components described herein, notably a cutter body  1050  including a substrate  301  and a superabrasive layer  302  overlying the upper surface  307  of the substrate  301 . The substrate  301  can further include a jacket  1041  having an inner surface  310  overlying, and in particular, abutting the side surface  305  of the substrate  301 . The jacket  1041  can further include an upper surface  1002  that is abutting the rear surface  316  of the superabrasive layer  302 . Notably, according to the illustrated embodiment, the jacket  1041  can be formed such that there may not necessarily be a flange overlying the side surface  306  of the superabrasive layer  302 , however, it will be appreciated that such configurations can be used. 
     The jacket  1041  can have a combination of an axially varying and a radially varying composition that can be enabled by the formation of layered regions  1045 ,  1046 , and  1047 , which are curvilinear shaped regions. Each of the layered regions  1045 - 1047  can have portions that are axially spaced apart from other portions of the layered regions  1045 - 1047 . Stated another way, for a particular radial position within the body of the jacket  1041 , traveling along a linear path at the same radial position parallel to the longitudinal axis  308 , the composition of the jacket  1041  can change with change in axial position along the length of the jacket  1041  through the layered regions  1045 - 1047 . Likewise, portions of each of the layered regions  1045 - 1047  can be radially spaced apart from other portion of the layered regions  1045 - 1047 . That is for a particular axial position along the length of the jacket  1041 , traveling along a linear path at the same axial position perpendicular to the longitudinal axis  308 , the composition of the jacket  1041  can change with change in radial position along the thickness of the jacket  1041  through the layered regions  1045 - 1047 . 
     According to one embodiment, each of the layered regions  1027 - 1029  can represent regions within the jacket  1041  having compositions that can be different from each other. In particular, the layered regions  1027 - 1029  can exhibit differences in the composition similar to the layered regions  1008 - 1010  of the embodiment of  FIG. 10A . Moreover, the layered regions  1027 - 1029  can have the same characteristics (e.g., differences in microstructure) as described in accordance with the embodiment of  FIG. 10A . 
     For example, the position  1042  within the layered region  1045  is axially and radially spaced apart from the position  1043  within the layered region  1046 , and particularly, the position  1042  can have a composition that is different from the composition of the position  1043 . Moreover, the position  1043  within the layered region  1046  is axially and radially spaced apart from the position  1044  within the layered region  1047 , and particularly, the position  1043  can have a composition that is different from the composition of the position  1044 . Likewise, the positions  1042  and  1044 , which are axially and radially spaced apart from each other, can have a difference in composition. The layered regions  1045 - 1047  can have compositions wherein the content of at least one species is different as compared to the content of the same species within any of the other layered regions  1045 - 1047 . Additionally, the layered regions  1045 - 1047  can have a composition, wherein at least one chemical species is present within one of the layered regions and can be absent from one of the other layered regions  1045 - 1047 . Furthermore, it will be appreciated that while the jacket  1041  is illustrated as having three layered regions, more or less layered regions can be used to construct the jacket  1041 . 
     According to one embodiment, the cutting element  1040  is formed such that the layered region  1047  includes a tungsten carbide material and that can have a different amount of catalyst material as compared to the compositions within the layered regions  1045  and  1046 . In particular, the composition within the layered region  1047  is formed such that the cobalt content is less than the cobalt content of the compositions within the layered region  1045  and/or layered region  1046 . 
     In another embodiment, the layered region  1047  can be formed of a material having an entirely different composition as compared to the layered region  1045  and/or the layered region  1046 . For example, in one embodiment, the layered region  1047  can be made of a polycrystalline material, such as polycrystalline diamond, while the layered region  1045  and/or the layered region  1046  can be made of a tungsten carbide material. 
       FIGS. 11A-11C  include cross-sectional illustrations of cutting elements employing ring members. In particular, the cutting elements combine the ring member feature with jackets, and particularly, jackets having varying compositions.  FIG. 11A  includes a cross-sectional illustration of a cutting element according to an embodiment. The cutting element  1100  can include the components described herein, including a substrate  301  and a superabrasive layer  302  overlying the upper surface  307  of the substrate  301 . The substrate  301  can further include a jacket  1003  having an inner surface  310  overlying, and in particular, abutting the side surface  305  of the substrate  301 . The jacket  1003  can further include an upper surface  1002  that is abutting the rear surface  316  of the superabrasive layer  302 . Notably, the jacket  1003  can be formed such that there may not necessarily be a flange overlying the side surface  306  of the superabrasive layer  302 , however, it will be appreciated that such configurations can be used. 
     The jacket  1003  can have a radially varying and/or an axially varying composition having the features described in other embodiments herein. In particular, the jacket  1003  can have layered regions  1008 ,  1009 , and  1010  that are radially spaced apart from each other and extend generally parallel to the longitudinal axis  308  of the cutter body  1050 . Each of the layered regions  1008 - 1010  can represent regions within the jacket having compositions that can be different from each other. The layered regions  1008 - 1010  can have compositions wherein the content of at least one species is different as compared to the content of the same species within any of the other layered regions  1008 - 1010 . Additionally, the layered regions  1008 - 1010  can have a composition, wherein at least one chemical species (e.g., a catalyst material) is present within one of the layered regions  1008 - 1010  and can be absent from one of the other layered regions  1008 - 1010 . Notably, the jacket  1003  can have a radially varying composition, such that the content of a catalyst material, such as cobalt, within the layered regions  1008 - 1010  are different compared to each other. 
     In certain embodiments, the jacket  1003  can be formed to have layered regions  1008 - 1010  wherein the compositions differ from each in a greater manner than the content of one chemical species. For example, the layered regions  1008 - 1010  can differ from each other in that one of the layered regions  1008 - 1010  can have an entirely different composition than another one of the layered regions  1008 - 1010 . In particular, the jacket  1003  can be constructed such that the layered region  1010  can include a polycrystalline material, such as polycrystalline diamond, wherein the one of the layered regions  1008  or  1009  can be formed of a completely different composition, such as tungsten carbide. In still other cutting elements, the jacket  1003  can include an outermost layer (e.g., layered region  1010 ) comprising a first composition, such as tungsten carbide, and the layered region  1009  abutting the outermost layer can have a second, different composition as compared to the first composition. In particular, the second composition of layered region  1009  can be a superabrasive material, such as polycrystalline diamond, cubic boron nitride, and a combination thereof. Other embodiments herein may utilize a combination of tungsten carbide overlying layers or regions of superabrasive material, such that the superabrasive layer acts to further limit effects of erosion. 
     Moreover, it will be appreciated, that the layered regions  1008 - 1010  can have a distinction in microstructure as compared to each other. Alternatively, while the jacket  1003  is illustrated as having discrete layered regions  1008 - 1010 , such radially varying composition can also be achieved through a gradient structure, which may not utilize discrete layered regions within the jacket. The difference between forming a jacket with discrete layered regions having discrete interfaces and a jacket having a gradient structure, wherein the discrete interfaces may not be identifiable, can be achieved through different forming processes, which will be described in more detail herein. 
     The cutting element  1100  further includes a ring member  1101  disposed between the superabrasive layer  302  and the substrate  301 . The ring member  1101  can offer additional erosion resistance for the cutting element  1100 , particularly in a location directly behind the superabrasive layer  302 . The ring member  1101  can be abutting the rear surface  316  of the superabrasive layer  302 . Additionally, the ring member  1101  can be abutting a surface of the substrate  301 , and particularly, a peripheral side surface  305  of the substrate  301 . Moreover, the ring member  1101  can be positioned between the substrate  301  and a layered region  1010  of the jacket  1003 , such that a portion of the jacket is overlying the ring member  1101 . Notably, the ring member  1101  can be positioned within the cutting element  1100  such that an exterior surface  1102  of the ring member is covered by a portion of the jacket  1003 . The ring member  1101  can extend around at least a fraction of the peripheral side surface  305  of the substrate  301 , and may extend peripherally along the entire peripheral length of the side surface  305  (e.g., through 360 degrees). Additionally, the ring member  1101  can extend for a fraction of the total length of the cutting element  1100  along the longitudinal axis  308 . Still, in other embodiments, the ring member  1101  can extend for the full length of the cutting element  1100 . 
     According to a particular embodiment, the ring member  1101  can include a polycrystalline material. Certain ring members can include a superabrasive material, such as diamond and/or cubic boron nitride. In one embodiment, the ring member  1101  can consist essentially of polycrystalline diamond. In another instance, the ring member  1101  can consist essentially of cubic boron nitride. 
     The ring member may act as a stop layer for erosion during use of the cutting element  1100 , since the ring member  1101  can be made of material having a greater erosion resistance than the jacket  1003 . Moreover, the ring member  1101  may facilitate releasable assembly of the jacket  1003 , such that after sufficient wear of the jacket  1003  and upon initiation of wear of the ring member  1101 , the jacket  1003  can be removed from the substrate and replaced with a new jacket. 
     It will be appreciated that while the ring member  1101  is illustrated as having a rectangular cross-sectional shape, other shapes can be utilized. For example, the ring member  1101  can include a host of other polygonal cross-sectional shapes, including for example, circular, elliptical, triangular, pentagonal, hexagonal, and the like. Certain cutting elements can employ a ring member  1101  having an irregular shape. Alternative ring members  1101  can have certain protrusions, gaps, recesses, and the like. 
     The ring member  1101  may have a shape that aids fitting and attachment between the jacket  1003  and the ring member  1101 . For example, particularly in the context of releasable and replaceable jackets, the jacket  1003  and the ring member  1101  can be attached by a snap-fit connection, interference-fit connection, complementary-shaped engagement structure (e.g., tongue-in-groove). In other instances, the ring member  1101  and the jacket  1003  can be mechanically bonded to each other, such as through a high temperature bond, such as a brazing process. 
       FIG. 11B  includes a cross-sectional illustration of a cutting element according to an embodiment. The cutting element  1120  can include the components described herein, notably a cutter body  1050  including a substrate  301  and a superabrasive layer  302  overlying the upper surface  307  of the substrate  301 . The substrate  301  can further include a jacket  1003  having an inner surface  310  overlying, and in particular, abutting the side surface  305  of the substrate  301 . The jacket  1003  can further include an upper surface  1002  that is abutting the rear surface  316  of the superabrasive layer  302 . Notably, according to the illustrated embodiment, the jacket  1003  can be formed such that there may not necessarily be a flange overlying the side surface  306  of the superabrasive layer  302 , however, it will be appreciated that such configurations can be used. 
     The cutting element  1120  further includes a ring member  1101  disposed between the superabrasive layer  302  and the substrate  301 . Notably, unlike the embodiment of  FIG. 11A , the ring member  1101  can be disposed within a recess of the substrate  301 , such that it is seated within an interior space of the substrate  301  body. The ring member  1101  can have any of the features noted in other embodiments. 
       FIG. 11C  includes a cross-sectional illustration of a cutting element according to an embodiment. The cutting element  1140  can include the components described herein, notably a cutter body  1050  including a substrate  301  and a superabrasive layer  302  overlying the upper surface  307  of the substrate  301 . The substrate  301  can further include a jacket  1003  having an inner surface  310  overlying, and in particular, abutting the side surface  305  of the substrate  301 . The jacket  1003  can further include an upper surface  1002  that is abutting a portion of the rear surface  316  of the superabrasive layer  302 . In particular designs, the jacket  1003  can be formed to have a flange  348  that extends along a portion of the superabrasive layer  302 . That is, the flange  348  can extend along and overlie at least a portion of the side surface  306  of the superabrasive layer  302 . Notably, according to the illustrated embodiment, the jacket  1003  can be formed such that there may not necessarily be a flange overlying the side surface  306  of the superabrasive layer  302 , however, it will be appreciated that such configurations can be used. 
     The cutting element  1120  further includes a ring member  1101  disposed between the superabrasive layer  302  and the substrate  301 . Notably, unlike the embodiment of  FIG. 11A , the ring member  1101  can be disposed within a recess of the substrate  301 , such that it is seated within an interior space of the substrate  301  body. Still, a portion of the ring member  1101  extends radially from the recess within the substrate  301  and is disposed within a recess of the jacket  1003 . In particular, the exterior surface  1102  of the ring member  1101  can be flush and parallel with the side surface  306  of the superabrasive layer  302 . The ring member  1101  can have any of the features noted in other embodiments. 
     The cutting elements herein may be formed by particular methods such that the components are properly oriented with respect to each other and forces between components are applied as described herein. In accordance with an embodiment, one method of forming includes forming the cutter body comprising the substrate and superabrasive layer as illustrated in embodiments herein. One particular method of forming the cutter body can include a high pressure high temperature (HP/HT) process. 
     In a HP/HT process, substrate material is loaded into a HP/HT cell with the appropriate orientation and amount of diamond crystal material, typically of a size of 100 microns or less. Furthermore, a metal catalyst powder can be added to the HP/HT cell, which can be provided in the substrate or intermixed with the diamond crystal material. The loaded HP/HT cell is then placed in a process chamber, and subject to high temperatures (typically 1450-1600° C.) and high pressures (typically 50-70 kilobar), wherein the diamond crystals, stimulated by the catalytic effect of the metal catalyst powder, bond to each other and to the substrate material to form a PDC product. It will be appreciated that the PDC product can be further processed to form a thermally stable polycrystalline diamond material (commonly referred to as “TSP”) by leaching out the metal in the diamond layer. Alternatively, silicon, which possesses a coefficient of thermal expansion similar to that of diamond, may be used to bond diamond particles to produce a Si-bonded TSP. TSPs are capable of enduring higher temperatures (on the order of 1200° C.) in comparison to normal PDCs. 
     The process of forming the cutting elements herein may further include a process of forming a jacket having the dimensions described herein and particularly a central opening for engagement of the cutter body therein. Various forming methods may be undertaken to form the jacket. For example, a one-step process can be utilized to form certain cutting elements of the embodiments herein. A one-step forming process can include the formation of the jacket in an HP/HT process, and particularly forming the cutter body and jacket in the same high pressure high temperature process. In certain instances, the formation of the cutter body and the jacket can be completed simultaneously, such that they are formed in the same chamber at the same time. Such a process may require a special HP/HT cell capable of accommodating both components. The result of the one-step forming process is the formation of a cutting element employing a jacket, wherein the cutter body and jacket are an integrally bonded, monolithic article. 
     In order to achieve certain characteristics of the embodiments herein, such as a jacket having radially varying and/or axially varying compositions, certain processing steps may be completed before the HP/HT forming steps to fabricate a pre-formed jacket article. For example, a pre-formed jacket article can be formed before the final HP/HT processing such that it includes a plurality of discrete layers, wherein each of the layers contains a particular composition and/or microstructure, such that the final-formed cutting element includes a jacket having an axially varying and/or radially varying composition. Suitable processes for forming a pre-formed jacket article can include pressing, molding, casting, forging, heat-treatment (e.g., sintering) and a combination thereof. The pre-formed jacket may not necessarily be a completely sintered object, and may be a green article, which is an unfinished and unsintered article that may have undergone some heat-treatment to provide strength to the article for handling. 
     In one particular instance, the pre-formed jacket article can be formed of a plurality of layers, wherein each of the layers are pre-formed individually and then combined together to form the assembled pre-formed jacket. For example, a first layered region can be formed having a particular composition and microstructure, such as through processes that can include molding, pressing, forging, heat-treatment, and a combination thereof. A second layered region can be formed from the same or different composition and microstructure and formed through similar processing. Notably, the first and second layered regions can be shaped in a manner such that they can be combined to form the pre-formed jacket. More layered regions can be formed as needed, and upon completion of the desired number of pre-formed layered regions, the layered regions can be combined and adhered to each other. The layered regions can be adhered through use of a bonding compound, heat treatment, or a combination thereof. 
     Alternatively, the pre-formed jacket can be formed by a series of successive molding, casting, pressing operations or a combination thereof. The successive forming process can be used to form a series of successive layered regions, wherein in each successive operation, the desired raw materials are selected to form a particular layered region within the pre-formed jacket. 
     In accordance with other embodiments, depending upon the material of the jacket selected, the jacket may be formed through a different method than the HP/HT process. In such embodiments, the jacket and cutter body can be formed into a cutting element via a two-step forming process, since the joining of the cutter body and jacket may not necessarily be completed in a single process (i.e., HP/HT process). The jacket can be formed by methods including machining, casting, molding, pressing, forging, sintering, and a combination thereof. 
     In the two-step forming process, after individually forming the cutter body (i.e., superabrasive layer and substrate) and the jacket, the cutter body and jacket may be joined together. As described herein, the cutter body and the jacket can be joined using certain types of connection mechanisms. In certain instances the jacket can be releasably affixed to the cutter body, such that the jacket is a replaceable member and can be disposed of after sufficient wear. In other designs, the jacket is fixably attached to the cutter body, and the connection between the cutter body and the jacket is permanent. 
     It will further be appreciated that in some processes, a bonding material may be placed at the interface between the jacket and the cutter body to facilitate joining the two components. Suitable bonding materials may be inorganic or organic materials. For example, the bonding material can be a braze material incorporating a metal or metal alloy material. Metal materials of particular use may include metal elements including for example, nickel, iron, manganese, chromium, tantalum, vanadium, titanium, cobalt, tungsten, and a combination thereof and a combination thereof. Notably, super-alloy metals as described herein can also be employed. 
     It is further contemplated that a mechanical force may be applied to the jacket, cutter body, or both to affect the fitting of the cutter body within the central opening of the jacket. In one particular instance, a force can be applied to the jacket to increase the inner diameter of the central opening to allow the cutter body to fit within the jacket. As such, in particular instances, the cutter body may be extruded into the jacket, such that a mechanical urging force is applied to the substrate to urge the cutter body into the central opening of the jacket, and thereby creating a cutting element wherein the jacket exerts forces (e.g., radial and axial forces) on the cutter body. 
     In other processes, a press fitting operation can be used to fit the components (i.e., the jacket and the cutter body) together. Press fitting operations can utilize the application of force on the cutter body and/or jacket to affect fitting of the jacket and cutter body together in a manner that the jacket exerts at least a radially compressive force on the cutter body. In particular instances, the press fitting operation can include the formation of a jacket having a central opening designed to allow the cutter body to fit within the central opening During the press fitting operation, the cutter body can be forced into the central opening of the jacket, such that the jacket is forced to expand and consequently, the jacket also applies opposite forces to the cutter body. In particular instances, it may be particularly suitable to introduce the cutter body into the jacket such that the superabrasive layer is first introduced into the central opening. The cutter body is axially displaced through force within the central opening until the proper fit is obtained and the cutter body is properly seated within the jacket. It will be appreciated that chamfered surfaces on the rear of the jacket or on the superabrasive layer or both may aid the initiation of the fitting operation. 
     Additionally, certain two-step forming processes may employ a temperature differential for fitting of the cutter body within the central opening of the jacket. The process of creating a temperature differential may include increasing the temperature of the jacket, such as by heating the jacket to a temperature greater than a temperature of the cutter body. Such a process may facilitate an increase in the dimensions of the jacket, such that the diameter of the central opening is increased sufficiently for fitting of the cutter body within the jacket. As such, the dimensions of the jacket may initially be created such that the cutter body may not necessarily fit within the central opening of the jacket. However, after providing a temperature differential between the two components, the cutter body and jacket can be combined such that the cutter body fits within the opening of the jacket. It will be appreciated that after fitting the components together, the temperature differential may be removed to affix the components to each other. A temperature differential may also be achieved by cooling the components, particularly the cutter body, such that the dimensions of the cutter body contract (i.e., are reduced) to a suitable degree to facilitate fitting of the components together. 
     After fitting the cutter body within the central opening of the jacket, a radially compressive force can be applied to the jacket and cutter body to physically reduce the size of the jacket and compress the jacket. Compression of the jacket can facilitate the creation of a frictional bond between the two components and the exertion of a radially compressive force on the cutter body by the jacket. It will be appreciated that certain mechanical features at the interface of the jacket and cutter body, particularly the substrate, may be utilized to facilitate locking engagement and maintaining the compressive state of the jacket. 
     Additionally, components herein may have distinct mechanical performance based on differences in microstructure. For example, the jacket can be formed of a cemented tungsten carbide material formed from a feed material that is distinct from the tungsten carbide feed material used to form the substrate. The feed material can be varied based on parameters such as size distribution of the grains, quality of the grains, and aspect ratio of the grains to affect certain mechanical properties. 
     While reference above is made to the differences in properties between the jacket and the substrate, such discussion is illustrative and it will be appreciated that such these differences may exists between other components based on a difference in composition and feed material. Particularly, these differences can exist between the intermediate layer and the substrate, and/or the intermediate layer and the jacket. 
     The cutting elements herein demonstrate a departure from the state-of-the-art. While cutter designs have been disclosed in the past to mitigate problems associated with mechanical strain, temperature-induced strain, and wear, typically the changes in cutter design have been directed to changing the configuration of the cutter table and/or substrate and the interface between these two components. By contrast, the embodiments herein are directed to cutting elements incorporating multiple components employing a cutter body, a jacket, a collar, multiple chamfers and/or radiused edges, compositionally graded jackets, and other features for improved performance. Embodiments herein further include a combination of features directed to the orientation between the components, different structures of the components (e.g., layered structures), various materials for use in the components, particular surface features of the components, and certain means of affixing the components to each other. Moreover, the cutting elements of the embodiments herein can be formed through particular forming methods not previously utilized in the art, which facilitate the features of the cutting elements herein. 
     The above-disclosed subject matter is to be considered illustrative, and not restrictive, and the appended claims are intended to cover all such modifications, enhancements, and other embodiments, which fall within the true scope of the present invention. Thus, to the maximum extent allowed by law, the scope of the present invention is to be determined by the broadest permissible interpretation of the following claims and their equivalents, and shall not be restricted or limited by the foregoing detailed description. 
     The Abstract of the Disclosure is provided to comply with Patent Law and is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. In addition, in the foregoing, various features may be grouped together or described in a single embodiment for the purpose of streamlining the disclosure. This disclosure is not to be interpreted as reflecting an intention that the claimed embodiments require more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive subject matter may be directed to less than all features of any of the disclosed embodiments. Thus, the following claims are incorporated into the description, with each claim standing on its own as defining separately claimed subject matter.