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

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 degrees C to 1300 degrees 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 degrees C; and above 900 degrees C, TiAl reacted with TiC to produce dense TiAl/Ti2AlC composites. The products sintered at 1200 degrees C had fine crystals and dense fibres, and the distribution of Ti2AlC particles in TiAl matrix was homogeneous. Crown Copyright (c) 2008 Published by Elsevier Ltd and Techna Group S.r.l. All rights reserved.