A cutter having regions of differing coefficient of thermal expansion

摘要

A cutter comprising a superhard construction includes a cutting edge defined by a rake face, and a flank extending therefrom, and a first region 37 and a second region 39, the first region 37 abutting the second region 39 along a boundary. The first region 37 has a different material composition from the second region 39, both or the second regions comprise superhard material. The material of the first region 37has a different coefficient of thermal expansion (CTE) from the material of the second region 39. The second region extends 39 around the peripheral edge of the first region 37 defined by the boundary to form a collar therearound.