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

摘要

TiAl/Ti_2AlC 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 deg C , Ti reacts with Al to form TiAl interme-tallics; above 900 deg C , C reacts with remain Ti to form TiC triggered by the exothermal reaction of Ti and Al; TiAl reacts with TiC to produce dense TiAll Ti_2 AlC composites . In the holding stage, ternary Ti_2 AlC develops to layered polycrystal and composites pyknosis in the meanwhile . The mechanism of synthesis and mierostructure was especially discussed.