Microstructure and Tensile Properties of Forged High Nb Containing Tial Alloy on Large Scale

Microstructure and tensile properties of canned forged Ti-45Al-(8-9)Nb-(W,B,Y) (at.%) were investigated. After canned forging at (α + γ) phase region, microstructure in the major part of the pancake was fully recrystallized duplex (DP) microstructure containing equiaxed γ grains and fine α2/γ lamellar colonies with a grain size of less than 30μm, while microstructure in the near surface zone was a mixture of fine-grained DP and retained cast structure. Due to solidification segregation, β (B2) phase existed at the grain boundaries and triple junctions. The alloy exhibited a good balance between both room temperature (RT) and high temperatures tensile properties, and the brittle-to-ductile transition temperature was about 760 °C. The fracture mode was predominantly transgranular fracture at both RT and high temperatures.