Influence of strain rate on the substructure evolution and yield behavior of Ti-6Al-4V

Based upon a study of the influence of strain rate on the substructure evolution and mechanical response of Ti-Al6-4V the following conclusions can be drawn: 1) The deformation substructure of Ti-6-4 is observed to depend on both temperature and strain rate. Deformation at quasi-static strain rates at 293K is characterized by planar slip bands in the alpha grains while the deformation substructure at high strain rates (e.g., 5000 s/sup )minus/1)) and at quasi-static rates at 77K consists of numerous deformation twins, )lreverse arrowbrace)1121)rreverse arrowbrace) type believed to be related to the starting texture and strain rate effects. 2) The constitutive equations based on the KocksMecking model have been successfully applied to predict the deformation response of Ti-6-4 to loading path changes involving a relatively narrow regime in strain rate and temperature. Changes in slip character or in deformation mechanism (e.g., deformation twinning) have been observed to correlate with changes in the expected flow behavior, although these results are beyond the current modeling procedures outlined in this paper. 11 refs., 6 figs