Yield Point Phenomenon and Serrated Yielding in Nb-40Ti-15Al

The ternary Nb-40Ti-15Al (at.%) intermetallic has an ordered B2-type crystal structure and shows appreciable ductility. Deformation is mainly accommodated in slip bands by the glide of b = 1/2 dislocations on {l_brace}110{r_brace} planes. The tensile behavior of this material has been studied at room temperature and at intermediate temperatures. Static and dynamic strain aging have been observed in certain temperature regimes. A model based on dislocation pinning by precipitates is proposed to explain the serrations observed during dynamic strain aging.