抄録
The results of our study on the heat treatment of TiC-50Ni·Cr·Co. (Ni/Cr/Co=3/1/1) cermets were described in the preceding report. Thereafter, experiments on TiC-50Ni·Cr·Co·Mo cermets containing 0.5 and 5.0 wt%Mo as a substitute for Co were continued. Specimens were vacuum-sintered at 1280°C for 1 hr and heat-treated in vacuum at 950° and 1150°C for up to 25 hrs, and at 1220∼1260°C for up to 5 hrs or quenched from 950∼1280°C. The changes of room-temperature properties of the alloys such as transverse-rupture strength, hardness, density, curie temperature and microstructure were observed as functions of heat treatment. It was noticed that the alloy containing 5.0%Mo, after prolonged heating, showed stabler strength and decrease of the hardness leading improved ductility, in connection with better dispersion of carbide grains and with the non-precipitation of chrome carbides, but these findings were in opposition to the results obtained in low Mo alloy.
