Microstructure characteristic for high temperature deformation of powder metallurgy Ti-47Al-2Cr-0.2Mo alloy

Hot compression tests of a powder metallurgy (P/M) Ti-47Al-2Cr-0.2Mo (at. pct) alloy were carried out on a Gleeble-3500 simulator at the temperatures ranging from 1000 °C to 1150 °C with low strain rates ranging from 1 × 10−3 s−1 to 1 s−1. Electron back scattered diffraction (EBSD), scanning electron microscope (SEM) and transmission electron microscope (TEM) were employed to investigate the microstructure characteristic and nucleation mechanisms of dynamic recrystallization. The stress-strain curves show the typical characteristic of working hardening and flow softening. The working hardening is attributed to the dislocation movement. The flow softening is attributed to the dynamic recrystallization (DRX). The number of β phase decreases with increasing of deformation temperature and decreasing of strain rate. The ratio of dynamic recrystallization grain increases with the increasing of temperature and decreasing of strain rate. High temperature deformation mechanism of powder metallurgy Ti-47Al-2Cr-0.2Mo alloy mainly refers to twinning, dislocations motion, bending and reorientation of lamellae.