Abstract
It was shown in a previous report by the present authors that high temperature transverse-rupture strength of TiC-Mo2C-Ni cermet was highly improved by the addition of a small amount of ZrC or HfC. Therefore, in the present study, the strengthening mechanism was investigated mainly for TiC-Mo2C-(1-40)%Ni cermets containing 1 mol%ZrC.
It was found that the binder phase can be plastically deformed less easily in ZrC contained alloys, so that the crack initiation load at carbide/carbide interfaces increases and the growth rate of stable cracks decreases. It was suggested that the decrease in diffusivity of the binder phase is responsible for the strengthening of the ZrC contained alloy, rather than the solution hardening in carbide phases.
