The phase transformation and microstructure of TiAl/Ti2AlC composites caused by hot pressing

Abstract: Two series of raw materials were adopted to form TiAl/Ti2AlC composites: Ti/Al/TiC and Ti/Al/C. Differential thermal analysis (DTA) of starting powers and X-ray diffraction (XRD) of samples sintered at different temperatures from 600°C to 1300°C by hot pressing were utilized to analyze the phase transformation and the mechanism of synthesis. Scanning electron microscopy (SEM) coupled with energy-dispersive spectroscopy (EDS) was utilized to investigate the morphology characteristics of the products. The experimental results showed that Ti reacted with Al to form TiAl intermetallics below 900°C; and above 900°C, TiAl reacted with TiC to produce dense TiAl/Ti2AlC composites. The products sintered at 1200°C had fine crystals and dense fibres, and the distribution of Ti2AlC particles in TiAl matrix was homogeneous. [Copyright &y& Elsevier]