A STUDY ON THE SYNTHESIS OF ULTRA-FINE IN SITU Ni3Al–Al2O3/TiC COMPOSITE POWDER

摘要

Titanium carbide (TiC) has a low density, relatively high thermal and electrical conductivity. TiC is also very stable, with a melting temperature of 3100°C and does not undergo phase transformations. These properties have attraction to apply cutting tool extensively. Recently, in order to improve the properties of cermet tool materials, most researches have been carried out on the development of new binder. Ni3Al intermetallic is an interesting material because it has a great advantage of application for some structural materials, especially at the high temperatures. Ni3Al has low density, high strength and good corrosion resistance properties, which recommend them for the application of high temperature structural material. In this study, we had investigated the effects of mechanical alloying time and annealing temperature on the Ni3Al–Al2O3/TiC phase formation. Raw powders to fabricate Ni3Al–Al2O3/TiC composite powders were Ni, Al, TiH2 and activated carbon. These powders were ball-milled in planetary milling jar in argon atmosphere. Ball-milled powders were annealed up to 1200°C in Ar + 4%H2 atmosphere. The mean particle size of 300 nm was obtained after 10 h ball-milling. Ni3Al–Al2O3/TiC composite powders were formed by annealing for 1 h over 1100°C.