Micro structural features and mechanical properties of Al-Al₃Ti composite fabricated by in-situ powder metallurgy route

In this paper, an in-situ powder metallurgy technique of fabricating near net shape particulate Al₃Ti-Al composite is developed. Titanium tri-aluminide particles were generated in aluminum matrix by solid state reactive diffusion of homogenous blended pure Ti and Al powders. Effects of titanium particle size, temperature and time of sintering on microstructure and mechanical properties of the composite were studied by X-ray diffraction analysis, scanning electron microscopy, energy dispersive X-ray spectroscopy and tensile testing. After 5 h sintering at 600 °C, Al₃Ti intermetallic particles were formed as the major second phase. By decreasing the titanium particle size or increasing the sintering time, the amount of Al₃Ti phase increased. Tensile strength of the composite was affected significantly by the amount of porosity and intermetallic phase as two dominant factors. By decreasing the amount of porosity or the average particle size of Ti powder, a significant increase in tensile strength was observed.