Effects of Microstructure on Deformation and Fracture Behavior of Titanium Alloys

摘要

The deformation and fracture behavior of Ti alloys with LM and BM microstructures under both monotonic and cyclic loading were investigated. The results indicate that the ductile rupture occurs with coarse LM microstructure under monotonic loading, since the crystal orientation of part lamellar is often changed by the annealing twins. While,for the BM microstructure, the deformation easy occurs with the dislocation multiplication and movement in both αp phase and lathlike second α phase.it leads the early yielding and larger plastic deformation before fracture. Under the cyclic loading,because the crack propagation direction can be hindered by the αp phase in BM microstructure, the fracture will be delayed by the present of αp phase,and also the resistance of crack propagation of αp phase in BM can be increased by the precipitation of α2 phase. It is found that after thermal exposure the fracture of the specimen become hardly with the α2 phase precipitated in αp phase.