Research on Equiaxed Microstructural Evolution and Tensile Properties ofTi-22Al-25Nb Alloy

Abstract:

The study focused on the evolution of equiaxed microstructural and its effect on the tensile properties in Ti-22Al-25Nb alloy. During the solution in O+B2 phase region, the primary lath O phase in microstructures obtained in isothermal forging in α₂+O+B2 phase region coarsened and became shorter and fine lath O dissolved into B2 matrix phase, while equiaxedα₂/O phase did not change significantly. A part of equiaxed O phase dissolved and rim O phase became thinner with higher solution temperature. During the aging in O+B2 phase region, aboundant of secondary fine lath O phase precipitate from B2 phase, and a little of α₂phase surronded with rim O transformed to O phase. Higher aging temperature resulted in coaser but less secondary lath O phase and thicker rim O phase, as well as lower tensile strength and higher ductility.