Characterization of creep behavior of TiAl alloy with high Nb content at elevated temperatures

摘要

Creep experiments of the TiAl alloy with high Nb content were conducted to consider both the temperature dependence and stress dependence of its creep behavior.The creep curves were characterized by Theta constitutive model,and Newton-Gauss method was applied to obtain the material parameters.Based on the rupture strain,the rupture life of the TiAl alloy was able to be predicted by Theta constitutive model.The results show that the creep curves of the TiAl alloy contain primary creep,secondary creep and tertiary creep stages,especially for the lower stress.The rupture life of the TiAl alloy decreases with the increase in either applied stress or temperature.Theta constitutive model is able to describe the creep deformation of the TiAl alloy accurately,and the predicted life agrees well with the experimental result.