Morphology and crystallographic orientation of the secondary α phase in a compressed α/β titanium alloy

The precipitation mechanism of secondary α phase in a compressed α/β titanium alloy was studied. With the influence of dislocation, the secondary α phase exhibits the irregular morphology rather than a lamellar colony. The mutually inclined groups of secondary α phase lamellae nucleate on the different crystallographic orientation of the β grain, obeying the Burgers orientation relationship. The secondary α phase lamellae always cross the β grain, which is explained well by the theory of sympathetic nucleation and variant selection.