PREPARATION OF NANOMETER-SIZE TIC PARTICULATE REINFORCEMENTS IN TI MATRIX COMPOSITES UNDER HIGH-PRESSURE

Nanometer size TiC particulate reinforcements were in-situ synthesized in Ti matrix composites by mixing graphite powder and titanium powder under high pressure (2.5 similar to 7.5 GPa) and high temperature (10 73 similar to 1573 K) conditions. The reinforcement, TiC, was formed i nside the material, instead of being inserted into the matrix interfac e wettability problems of the two materials were therefore avoided, an d well-bonded metal matrix particulate composites were achieved. The g rain sizes of TiC, which ranged from 10 nm to 40 nm, can be controlled by changing processing condition. The relationship between the grain sizes of TiC particulates and their microhardnesses, as well as the in fluence of pressure and temperature on the grain sizes of TiC, is disc ussed. (C) 1997 Acta Metallurgica Inc.