DISLOCATION EVOLUTION WITH CREEP STRAIN AND DISLOCATION EMISSION RELATED WITH ALPHA(2)-PHASE DISSOLUTION

Microstructural evolution of the lamellar structured Ti-46.6Al-1.4Mn-2 Mo (at.%) alloy (made by elemental powder metallurgy, EPM) during prim ary creep deformation under the condition of 800 degrees C/200 MPa is investigated using transmission electron microscopy (TEM). As the prim ary creep deformation is progressing, the density of the initial dislo cation is found to decrease very significantly. Two kinds of dislocati on generation modes related to the lamellar interfaces were observed; cross slip and bowing of the interfacial dislocations. And it is sugge sted that the applied stress play a significant role in the dissolutio n of alpha(2)-phase, and the interfacial dislocation emission and diss olution of alpha(2)-phase are closely related with each other in contr olling creep deformation rate. (C) 1997 Elsevier Science S.A.