Microhardness anisotropy in polycrystalline carbides of the transition metals of group VI

Abstract

1. Using the technique of hardness measurements with a square-based diamond indentor, microhardness-distribution curves were obtained for polycrystalline specimens of refractory carbides. The resulting microhardness-distribution data were employed for determining the degree of microhardness anisotropy in carbides of the transition metals of group VI. The highest values of microhardness are found on the end faces of hot-pressed specimens, which is attributable to texture formation. For fused carbides, the anisotropy of microhardness is less, while the frequency curve of Mo2C is shifted toward higher microhardness values. 2. On the end faces of specimens, the grains of compounds with the Mo2C structure are likely to arrange themselves so that their (2¯1¯10) and (10¯12) planes (hot-pressed specimens) or (10¯12) planes (fused specimens) lie on the surface. 3. The character of microhardness-distribution curves and their variation for the compounds investigated are linked with the crystallographic factors involved in the plastic deformation of carbides.