Prismatic and basal slip in Ti3Al II. Dislocation interactions and cross-slip processes

Abstract

Abstract In the first part, dislocation mechanisms controlling individual dislocation glide in prismatic and basal planes were studied and compared with results of atomistic calculations. In this second part, the plasticity of Ti3Al is studied in situ at an intermediate scale. The critical resolved shear stress (CRSS) of prismatic slip is shown to be controlled by the easy glide process of dislocations in the planes of high APB energy, and the CRSS of basal slip is shown to depend on the collective motion of several dislocation families forming a coplanar network. Other mechanical properties like work-hardening and ductility have been interpreted in terms of dislocation interactions, multiplications and cross-slip processes. The high Peierls-type frictional forces are thus surprisingly of minor importance for explaining the mechanical properties of Ti3Al.