Temperature dependence of yield stress, deformation mode and deformation structure in single crystals of TiAl (Ti−56 at.% Al)

Abstract

Listen

Translate article

Abstract The plastic deformation behaviour of single crystals of TiAl with a composition of Ti-56 at.% Al has been studied in compression as a function of crystal orientation in the temperature range from −196 to 1100°C. The profile of yield stress-temperature curves for all orientations studied can be divided into three temperature regions; the yield stress rapidly decreases with increasing temperature at both low and high temperatures and an anomalous increase in yield stress is observed at intermediate temperatures, exhibiting a peak at 700–1000°C depending on crystal orientation. Both ordinary and [101] superlattice slip exhibit an anomalous increase in critical resolved shear stress (CRSS). However, the extent of the anomaly associated with the former slip is much smaller than that for the latter slip. The CRSS for [101] slip depends on crystal orientation. In the anomalous temperature region, the CRSS exhibits very small strain-rate sensitivity and thermal reversibility24Jun1996. Superlattice disloc...