A polycrystalline cubic boron nitride, PCBN, material is provided. The material comprises between 30 and 90 weight percent cubic boron nitride (cBN) and a matrix material in which the cBN particles are dispersed. The matrix material comprises particles of an aluminium compound; the matrix material particles having a d50 when measured using a linear intercept technique of no more than 100 nm.

A cutting element has a thermally stable polycrystalline diamond layer formed on an upper side of a polycrystalline diamond layer and having a cutting face opposite the polycrystalline diamond layer, a transition layer on a side of the polycrystalline diamond layer opposite the thermally stable polycrystalline diamond layer, and a non-planar interface between the transition layer and the polycrystalline diamond layer, the non-planar interface having a perimeter exposed around a side surface of the cutting element and encircling an interior of the non-planar interface, and an uppermost portion of the perimeter being a distance from the cutting face greater than an axial distance between the cutting face and the interior.

A superhard polycrystalline construction comprises a body of polycrystalline superhard material comprising a superhard phase, and a second phase dispersed in the superhard phase, the superhard phase comprising a plurality of inter-bonded superhard grains. The second phase comprises particles or grains that do not chemically react with the superhard grains, and/or do not inter-grow, and form between around 1 to 30 volume % or wt % of the body of polycrystalline superhard material.

A cBN sintered compact includes a binder phase that contains a TiAl alloy containing at least one of the Si, Mg, and Zn elements, Ti.sub.2CN, TiB.sub.2, AlN, and Al.sub.2O.sub.3; the ratio I.sub.Ti2CN/I.sub.TiAl is 2.0 or more and 30.0 or less, wherein I.sub.Ti2CN represents the intensity of the Ti.sub.2CN peak appearing at 2? from 41.9? to 42.2? and I.sub.TiAl represents the intensity of the TiAl alloy peak appearing at 2? from 39.0? to 39.3? in XRD; and, in the mapped image of each element of Ti, Al, Si, Mg, and Zn by Auger electron spectroscopy, the ratio S.sub.TiAlM/S.sub.TiAl, is 0.05 or more and 0.98 or less wherein S.sub.TiAlM represents the average area of the portions wherein Ti, Al and at least one selected from the group consisting of Si, Mg, and Zn overlap and S.sub.TiAl represents the average area of the portions where Ti and Al overlap.

A cubic boron nitride sintered body including cubic boron nitride and a binder phase, wherein: a content ratio of the cubic boron nitride is 85 volume % or more and 95 volume % or less, a content ratio of the binder phase is 5 volume % or more and 15 volume % or less, the binder phase contains Co.sub.3W.sub.3C, W.sub.2Co.sub.21B.sub.6, and an Al compound, and I.sub.B/I.sub.A is 0.02 or more and 0.15 or less, I.sub.C/I.sub.A is 0.02 or more and 1.00 or less, and I.sub.C?I.sub.D, where I.sub.A denotes an X-ray diffraction peak intensity of a (111) plane of the cubic boron nitride, I.sub.B denotes an X-ray diffraction peak intensity of a (400) plane of the Co.sub.3W.sub.3C, I.sub.C denotes an X-ray diffraction peak intensity of a (420) plane of the W.sub.2Co.sub.21B.sub.6, and I.sub.D denotes an X-ray diffraction peak intensity of a (001) plane of WC.

Polycrystalline diamond may include a working surface and a peripheral surface extending around an outer periphery of the working surface. The polycrystalline diamond includes a first volume including an interstitial material and a second volume having a leached region that includes boron and titanium. A method of fabricating a polycrystalline diamond element may include positioning a first volume of diamond particles adjacent to a substrate, the first volume of diamond particles including a material that includes a group 13 element, and positioning a second volume of diamond particles adjacent to the first volume of diamond particles such that the first volume of diamond particles is disposed between the second volume of diamond particles and the substrate, the second volume of diamond particles having a lower concentration of material including the group 13 element than the first volume of diamond particles.

A composite sintered material includes: a plurality of diamond grains having an average grain size of less than or equal to 10 m; a plurality of cubic boron nitride grains having an average grain size of less than or equal to 2 m; and a remainder of a binder phase, wherein at least parts of adjacent diamond grains are bound to one another, the binder phase includes cobalt, in the composite sintered material, a content of the diamond grains is more than or equal to 30 volume % and less than or equal to 94 volume %, a content of the cubic boron nitride grains is more than or equal to 3 volume % and less than or equal to 40 volume %, and a content of the cobalt is more than or equal to 3 volume % and less than or equal to 30 volume %.

A superhard polycrystalline construction comprises a body of polycrystalline superhard material, comprising a mass of superhard grains exhibiting inter-granular bonding and defining a plurality of interstitial regions therebetween, the superhard grains having an associated mean free path and a non-superhard phase at least partially filling a plurality of the interstitial regions and having an associated mean free path. The median of the mean free path associated with the non-superhard phase divided by (Q3Q1) for the non-superhard phase being greater than or equal to 0.50, where Q1 is the first quartile and Q3 is the third quartile; and the median of the mean free path associated with the superhard grains divided by (Q3Q1) for the superhard grains being less than 0.60. The body of polycrystalline superhard material has a first surface having a surface topology comprising one or more indentations therein and/or projections therefrom. There is also disclosed a method of forming such a construction.

A method of forming a super hard polycrystalline construction comprises forming a liquid suspension of a first mass of nano-ceramic particles and a mass of particles or grains of super hard material having an average particle or grain size of 1 or more microns, dispersing the particles or grains in the liquid suspension to form a substantially homogeneous suspension, drying the suspension to form an admix of the nano-ceramic and super hard grains or particles, and forming a pre-sinter assembly comprising the admix. The pre-sinter assembly is then sintered to form a body of polycrystalline super hard material comprising a first fraction of super hard grains and a second fraction, the nano-ceramic particles forming the second fraction. The super hard grains are spaced along at least a portion of the peripheral surface by one or more nano-ceramic grains, the super hard grains having a greater average grain size than that of the grains in the second fraction which have an average size of less than around 999 nm.

Polycrystalline diamond includes a working surface and a peripheral surface extending around an outer periphery of the working surface. The polycrystalline diamond includes a first volume including an interstitial material and a second volume having a leached region that includes boron and titanium. A method of fabricating a polycrystalline diamond element includes positioning a first volume of diamond particles adjacent to a substrate, the first volume of diamond particles including a material that includes a group 13 element, and positioning a second volume of diamond particles adjacent to the first volume of diamond particles such that the first volume of diamond particles is disposed between the second volume of diamond particles and the substrate, the second volume of diamond particles having a lower concentration of material including the group 13 element than the first volume of diamond particles. Various other articles, assemblies, and methods are also disclosed.