Preparation of TiAl/Ti_2AlC Composites with Ti/Al/C Powders by In-situ Hot Pressing

摘要

TiAl/Ti2AlC composites were prepared by in-situ hot pressing of Ti/Al/C powders mixtures and sintered at different temperatures were investigated by X-ray diffraction （XRD） of samples. The reaction procedure of Ti-Al-C system could be divided into three stages. Below 900 ℃, Ti reacts with Al to form TiAl intermetallics; above 900 ℃, C reacts with remain Ti to form TiC triggered by the exothermal reaction of Ti and Al; TiAl reacts with TiC to produce dense TiAl/Ti2AlC composites. In the holding stage, ternary Ti2AlC develops to layered polycrystal and composites pyknosis in the meanwhile. The mechanism of synthesis and microstructure was especially discussed.