Characterization of TiAl-based alloy with high-content Nb by powder metallurgy

Powders with nominal composition of Ti-45Al-10Nb (mole fraction, %) were prepared by mechanical ball milling and were then consolidated by hot-pressed sintering in vacuum atmosphere. The microstructures of 12 h-milling composite powders and sintered bulk materials were characterized by OM, XRD, SEM and EDX. The results showed that the composite powders were completely homogeneous, and fine-grained Ti/Al/Nb composite powders were made. The microstructure of the consolidated alloy was composed of fine equiaxed grains with large pure Nb particles. And the results also indicated that the compressive strength and ductility of the sintered TiAl-based bulk material at RT could be improved effectively by adding 10% Nb element. The yield strength (σ0.2) and fracture strength (σb) of the alloy were 842 MPa and 1314 MPa, respectively, and the compressive ductility (δp) was 12.4%.