New technique for producing items from TiC-(Ni-alloy) cermet for severe application conditions

Abstract

A new technique for producing complex-shaped items from wear-resistant TiC-(Ni-alloy) cermets is described. Cermets are produced by infiltration of TiC-preforms with Ni-alloy, which combines the advantages of powder metallurgy and casting. A special vacuum induction furnace is designed to effectively implement the new technique, which enhances the production capacity and quality of a cermet item against other known technologies. The structure of new cermets is characterized by a uniform distribution of TiC grains in the Ni matrix. During infiltration, a considerable part of tungsten and some part of molybdenum migrate in TiC grains forming solid solution shells on them. The shell ensures the connection between TiC and Ni-alloy and high physical and mechanical properties of the cermet. The physical and mechanical properties of the TiC-(Ni-alloy) cermet at temperatures up to 1100 °С and the results of practical use of items from cermets in production are presented. The shop tests showed the increase of the durability of a cermet ball valve by more than 6 times as compared with conventional wedge valves.