Microstructure and mechanical properties of annealed Ti−6Al−3Nb−2Zr−1Mo titanium alloys

Ti−6Al−3Nb−2Zr−1Mo alloys were prepared by forging and annealing at 980 ℃. The microstructure and mechanical properties of the annealed alloys on the different sections were studied by scanning electron microscopy (SEM) and electron back-scattered diffraction (EBSD). The results show that, compared with the forged alloys, the content of α phase in the annealed Ti−6Al−3Nb−2Zr−1Mo alloys decreases, and the content of the metastable β phase increases. During the cooling in the air, the metastable β phase is transformed into the secondary α phase and a small amount of β phase. After annealing at 980 ℃, α-Ti in Ti−6Al−3Nb−2Zr−1Mo alloys exhibits the texture types of RD//[$\bar {1}$2$\bar {1}$0] and FD//[0001], where RD is the forging compression direction (forging direction), and FD is the free extension direction of forging. The fracture morphology of Ti−6Al−3Nb−2Zr−1Mo alloys along the different tensile direction is mainly ductile fracture, and the fracture mode shows the micropore aggregation fracture. When the annealed alloys are stretched in RD direction, the size of the dimple is larger, and the corresponding elongation is superior to that in any other direction.