Effect of Nb or Mo addition on ductile-brittle transition behaviour of polycrystalline TiC

Abstract

In order to clarify the effect of Nb or Mo addition on ductile-brittle transition behaviour of titanium carbide, sintered TiC, TiC-10 mol%Nb and TiC-10 mol%Mo have been studied using a three-point bending test at temperatures from room temperature to 2020 K, and the fracture surface has been observed by scanning electron microscopy (SEM). It is found that the Nb addition decreases the ductile-brittle transition temperature (DBTT) of TiC by 400 K and increases the ductility, whereas little change of the behaviour was observed when Mo was added. The effect of Nb addition is discussed from the viewpoint of ability for plastic deformation.