Research on high temperature deformation behavior and constitutive relation of Ti2AlNb alloy

Abstract

A high-temperature plastic deformation is a failure form of Ti2AlNb alloy that deserves attention in the service process of aero-turbine engines. In this study, the deformation behavior of Ti2AlNb alloy has been studied through compression at 900 ~1100 °C and strain rates of 0.1 s−1, 0.01 s−1, and 0.001s−1. Then, the constitutive model of Ti2AlNb alloy has been established based on the true stress-strain curve. The results show that Ti2AlNb alloy has a high sensitivity to strain rate and temperature at the experimental condition. Ti2AlNb alloy still maintains good resistance to deformation at 900 °C, and the microstructure at the core region is basically unchanged after compression. In the boundary region, the microstructure changes significantly under the influence of stress. However, the yield strength of Ti2AlNb alloy decreases to about 5 MPa at 1100 °C, 0.001s−1, and the microstructure of the alloy has significant transformation which the O-phase structure decomposes and forms the α2 strip structure.