SHS compaction of TiC cermets using mechanically activated mixtures

Abstract

This paper focuses on obtaining cermet composite materials by SHS compaction. The study covers the effect of mechanical activation of metal components contained in reaction mixtures based on the Ti + C + Cr + Ni system when treated with grinding media in a ball mill. Two mechanical activation methods were used for Ti, Cr and Ni metal powders. In the first method, Cr and Ni powders were activated with grinding media separately from other reaction mixture components, and then mixed with titanium and carbon black powders. It is shown that the preliminary mechanical activation of inert components reduces the temperature and rate of combustion and increases the average size of carbide grains. In the second method, Ti + + Cr, Ti + Ni, and Ti + Cr + Ni powder mixtures were jointly processed in a ball mill, and then mixed with carbon black. This method provided mechanical activation of titanium particles with a minimum effect of grinding media on Cr and Ni powders. This led to an increase in the combustion rate and temperature, a decrease in the average size of carbide grains, and an increase in the composite structure homogeneity. A mechanism is proposed for the interaction of reagents (Ti + C) with the participation of activated Cr and Ni particles in combustion and structure formation zones, according to which the mechanical activation of inert components leads to their direct participation in the reaction interaction of titanium with carbon, which determines a decrease in the combustion rate and temperature and affects the fineness and structural homogeneity of compact composites. The results obtained were used to increase the structural homogeneity and fineness of the STIM-3B composite (Grade 3B synthetic hard tool material).