Microstructure of （TiB+TiC）/TC18 Titanium Matrix Composite Undergoing Heat Treatment

Three kinds of Ti-5Al-5Mo-5V-1Fe-1Cr titanium matrix composites reinforced with trace amount of TiB and TiC were fabricated via a consumable vacuum arc-remelting furnace in this work.The reinforcements were produced during solidification by the chemical reactions between B₄C and Ti.The mass fractions of B₄C were 0.1%,0.2% and 0.4%,respectively. The as-cast ingots were subjected to thermomechanical processing and heat treatment.The β phase in the composites was significantly refined.However,with increase of the B₄C content,the refining extent of β grains was not linearly related but increased more and more slowly.It was suggested that this should be related to the accelerating effects of the reinforcements on the merging of β grains.