Structural stability，microstructure and mechanical behavior of Ti-10V-2Fe-3Al alloy

In the present study, Ti-10V-2Fe-3Al (Ti-1023) alloy was prepared by vacuum consumable melting and forging technique. The structural stability, microstructural evolution and mechanical behavior of the alloy were systematically investigated by X-ray diffraction, transmitting electron microscopy and mechanical testing. It is indicated that the structural stability, microstructure and mechanical behavior of Ti-1023 alloy are closely related to the cold deformation and heat treatment. Regardless of the solution treatments in single β phase region (833 ℃) or α + β phase region (753 ℃), double yielding occurs in the stress-strain curves of the alloy. This suggests that the β phases in the alloys with above solution treatments possess low structural stability, and stress induces β→α" martensitic transformation, leading to double yielding behavior. Severe cold rolling deformation and stress/strain induced martensitic transformation gives rise to the refinement of β grains and martensite variants. Since numerous dislocations and grain/phase boundaries induced by severe cold deformation can be used as nucleating sites for the precipitation of α phase, a large amount of fine α phase is precipitated out of the cold rolled Ti-1023 alloy after short aging at 550 ℃, therefore,the alloy exhibits a good balance between strength and ductility.