TISI2 COMPOSITES REINFORCED WITH IN-SITU SYNTHESIZED TIC AND SIC

Attrition milling followed by hot isostatic pressing and heat treatmen t was employed to produce TiSi2 matrix composites in situ reinforced w ith Tic and SiC. Phase transformations and microstructures of the comp osites were characterized by means of x-ray diffraction, scanning elec tron microscopy and energy-dispersive x-ray spectroscopy. TiSi, with 0 .5w/o and 2w/o C was hot isostatically pressed at 1473K for 1h in argo n and heat treated at 1473K for 12, 24 and 72h, respectively. Density and hardness were measured and the fracture toughness calculated from hardness. The in situ carbides improved room temperature hardness and toughness of the TiSi2. As-cast TiSi2 was also investigated and its pr operties compared with the powder processed material.