Abstract
Mechanical properties such as transverse-rupture strength and hardness of β-(10-20)% Ni alloy with WC up to 8% in β phase were studied, in comparison with those of TiC-Ni, TiC-(15-20)% Mo2C-Ni and β-(15-20)% Mo2C-Ni alloys having the same amount of binder. Four sorts of specimens were in vacuum sintered at various temperatures for 1 hr.
Results obtained were as follows: (1) The grain size of carbide in β-base alloys decreased with increasing WC contents and this decrease appeared to become constant at the WC contents more than about 5 %. In this case, the grain size of β-base alloys was smaller than that of TiC-base alloys generally in the following order; β-Mo2C-Ni<β-Ni<TiC-Mo2C-Ni<TiC-Ni. (2) Anomalous carbide, occluding a plateshaped titanium. carbide, was not observed in β-Mo2C-Ni alloy in contrast to TiC-Mo2C-Ni alloy. (3) The hardness of β-base alloys was naturally increased with increasing WC contents. The hardness of S(5%WC)-Ni alloy was extremely high among others at a definite value of mean free path up to about 0.15 μ. The strength of β(5%WC)-Mo2C-Ni alloy was most excellent at a definite value up to about 0.30.4 μ. Examinations of both strength and hardness of various alloys showed that β-Ni alloy with 5%WC or more was most superior to other alloys, when the hardness above approximately 1500Hv was required. (4) The excellent mechanical properties of β-Ni alloy above mentioned were considered to be partially due to high hardness of β phase, and partially due to high resistance to crack propagation along carbide-carbide interface.
