| 摘要 |
A superhard polycrystalline construction comprises a body of polycrystalline superhard material having a first region and a second region adjacent to and bonded to the first region by intergrowth of grains of superhard material. The first region comprises a plurality of alternating strata or layers, each having a thickness in the range of around 5 to 300 microns. One or more strata or layers in the second region have a thickness greater than the thicknesses of the individual strata or layers in the first region. The alternating layers or strata in the first region comprise first layers or strata alternating with second layers or strata, the first layers or strata being in a state of residual compressive stress and the second layers or strata being in a state of residual tensile stress. One or more of the layers or strata in the first or second regions comprise a mass of superhard grains exhibiting inter-granular bonding and defining a plurality of interstitial regions therebetween, the superhard grains and a non-superhard phase at least partially filling a plurality of the interstitial regions. The median of the mean free path associated with the non-superhard phase divided by (Q3−Q1) for the non-superhard phase is 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 (Q3−Q1) for the superhard grains is less than 0.60. |
