Effects of Carbon Content on the Structure of Intermediate Phase in TiC-Ni-Mo alloys

Abstract

Changes in various properties of TiC-Ni-Mo alloys during sintering process were observed to study the effect of carbon content on the structure of intermediate phase formed around the TiC grain. The results are as follows.(1) The wetting of TiC by Ni-Mo alloy were improved by increasing carbon content.(2) With an increase in the carbon content, the carbide grains changed from angular to spherical forms. The grain size and the thickness of the intermediate phase of carbide were reduced.(3) The structure of the intermediate phase were examined by X-ray microanalyser as follows. These results were demonstrated clearly by the presence of a molybdenum-rich zone at the edge of carbide coupled with a molybdenum-free region in the core of grains.As the carbon content in TiC-Ni-Mo alloys increases, this molybdenum-rich zone was found to approach the core boundary, and the diffusion of nickel from the liquid nickel into the intermediate phase and the solution of carbide into the nickel binder were reduced.