PRISMATIC AND BASAL SLIP IN TI2AL .2. DISLOCATION INTERACTIONS AND CROSS-SLIP PROCESSES

In the first part, dislocation mechanisms controlling individual dislo cation glide in prismatic and basal planes were studied and compared w ith results of atomistic calculations. In this second part, the plasti city of Ti3Al is studied in situ at an intermediate scale. The critica l resolved shear stress (CRSS) of prismatic slip is shown to be contro lled by the easy glide process of dislocations in the planes of high A PE energy, and the CRSS of basal slip is shown to depend on the collec tive motion of several dislocation families forming a coplanar network . Other mechanical properties like work-hardening and ductility have b een 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 pr operties of Ti3Al.