The microstructure and fracture toughness of a bimodal and basket-weave TC17 titanium alloys linear friction welded joint were investigated to meet the manufacturing demands of titanium alloy dual-performance blisk. Metallographic examination reveals that fine-grains with metastable phases are formed in the welding zone (WZ)

thermoplastic deformed microstructures with partially dissolved primary α

p

phases are formed in the thermo-mechanical affected zone (TMAZ). Fracture toughness examination shows that the fracture toughness of the WZ and TMAZ is significantly lower than that of the base metals

resulting in an obvious brittle tendency of the joint. However

the postweld annealing heat treatment can decompose the metastable phases into the equilibrium α+β phases in the joint

which can alleviate the brit

tle tendency of the joint to a certain extent.