The Structure, Mechanical Properties and Deformation Behavior of Ti-Al and Ti-Al-X Alloys

摘要

Strengthening due to the precipitation of the ordered alpha sub 2 phase (based on Ti3X) was studied in binary and ternary Ti-Al-X3(where X = Sn, Ga, In or Pb) alloys. The observed strengthening can be separated into two principal components; one due to the dislocation/ordered particle interaction and the other due to dislocation/precipitate stress field interactions. The former of these appears more important in some cases, e.g., Ti-Al-Sn alloys; whereas the latter appears to predominate in other cases, e.g., Ti-Al-Ga alloys. The brittleness of single phase Ti3Al was shown to be related to slip morphology and the decreased extent of glide with increasing Al content. The marked improvement in strength and ductility of the Ti3(Al0.5Ga0.5) and Ti3(Al0.25Ga0.75) compounds results from the phase separation into alpha sub 2 + Ti2Ga with an accompanying change in slip morphology and an increase in the extent of glide. (Author)