An Analysis of Strength of WC-TiC(TaC)-Ni Alloys

Abstract

It has been revealed in previous experiments that the transverse-rupture strength of various cemented carbides is generally dominated by the microstructural defects, so that the strength can be quantitatively expressed, by considering the dimension and location of the defects. In the present study, the same subject was undertaken, using WC-(0-25)%TiC-16vol%Ni and WC-(0.1-20)%TaC-16vol%Ni alloys in order to make clear the influence of addition carbides on the strength of WC-Ni alloy. The results were compared with those in WC-TiC(TaC)-16vol%Co alloys.
The following results were obtained: It was confirmed that the strength of those alloys was also controlled by the microstructural defects (pores, carbide agglomerates, etc.). The σ₀ values (the strength of sound matrix with none of defects) of WC-Ni alloy sharply decreased from about 700kg/mm² to about 350-400kg/mm² (according to JIS) by a small addition of TiC(TaC), showing that the sharp decrease in the strength of WC-Ni alloy by addition of TiC(TaC) seems to be substantial. The above results are similar to those in WC-TiC(TaC)-Co alloys. The difference in the ao values between WC-TiC-Ni and WC-TaC-Ni, and between WC-TiC(TaC)-Ni and WC-TiC(TaC)-Co alloys was in detail discussed.