Effects of thermal exposure on cyclic deformation and fracture behavior of Ti600 titanium alloy

Effects of thermal exposure on cyclic deformation and fracture behavior of Ti600 alloy were investigated by laser scanning confocal microscope (LSCM), scanning electron microscope (SEM) and transmission electron microscope (TEM). The results demonstrated that both the nonthermal exposure (NTE) specimens and the thermal exposure (TE) specimens showed the cyclic softening, within a total strain amplitude range from ±0.45% to ±1.00%. During thermal exposure, since the harder α2 (Ti3Al) phase precipitated in the αp (primary α) phase, the resistance of crack propagation of αp phase could be increased by the precipitation of α2 phase. Therefore, the fracture behavior of TE specimens is different with that of NTE specimens. For the NTE and TE specimens, the crack mainly passes through the αp phase with “cutting” and “bypass”, respectively.