Microstructures and Mechanical Properties of (Ti-42 mo1% Al Alloy+TiC) Composite Materials Produced by HIP Method

Abstract

TiC added (TiAl+Ti₃Al) aluminide composites with 0, 5, 10, 15 and 20 vol%TiC were produced by powder metallurgical method using Ti-42mol%Al prealloyed matrix powder and TiC powder. Those blends were sintered by HIP method. Microstructures, mechanical properties and oxidation resistance of obtained compacts were investigated. The matrices of compacts were found to be consisting of TiAl and Ti3Al phases regardless of whether TiC was added. Both lamellar structures within grains whose sizes were estimated at less than 100μm and equiaxed grain structures were observed for matrix. On the other hand, the formation of Ti₂A1C phase for TiC added alloys was confirmed. The flow stress was increased with increase of TiC volume, which contrasted with the decrease of fracture stress and fracture strain. Measured mass gain of no less than 300 g/m² for any specimens at 1223 K for 86.4ks suggested that addition of TiC has little effect on improving the oxidation resistance.