Microstructure and mechanical properties of Ti-22Al-24Nb-0.5 EBW

Abstract:

The Ti-22Al-24Nb-0.5Mo electron beam weld was investigated. The FZ is composed of fully collunar B2 grains in the FZ center and the dentritic B2 grains on top and bottom of the weld. Their distribution is symmetrical to the fusion line center. Two post-weld annealing schedules, namely 850_oC/2hr/AC (anneal) and 980_oC/2hr+850_oC/24hr/AC (solution treat + anneal), have been used. The STA weld exhibits a coarser O phase than the annealed weld in the FZ and the α₂ phase reappeared.The tensile strength of the welds for these two annealing conditions are similar at room temperature, while the annealed weld is a little stronger at 650_oC. The creep rupture life of the STA weld is higher, and the fracture mode is intergranular for both annealed and STA welds.