An Analysis on the Constitutive Models for Forging of Ti6Al4V Alloy Considering the Softening Behavior

作者：Souza Paul M^*; Beladi Hossein; Singh Rajkumar P; Hodgson Peter D; Rolfe Bernard

来源：Journal of Materials Engineering and Performance, 2018, 27(7): 3545-3558.

DOI：10.1007/s11665-018-3402-y

• constitutive equation
• EM plus Avrami model
• isothermal forging
• plastic deformation mechanisms
• titanium alloys

This paper developed high-temperature deformation constitutive models for a Ti6Al4V alloy using an empirical-based Arrhenius equation and an enhanced version of the authors' physical-based EM + Avrami equations. The initial microstructure was a partially equiaxed alpha + beta grain structure. A wide range of experimental data was obtained from hot compression of the Ti6Al4 V alloy at deformation temperatures ranging from 720 to 970 A degrees C, and at strain rates varying from 0.01 to 10 s(-1). The friction- and adiabatic-corrected flow curves were used to identify the parameter values of the constitutive models. Both models provided good overall accuracy of the flow stress. The generalized modified Arrhenius model was better at predicting the flow stress at lower strain rates. However, the model was inaccurate in predicting the peak strain. In contrast, the enhanced physical-based EM + Avrami model revealed very good accuracy at intermediate and high strain rates, but it was also better at predicting the peak strain. Blind sample tests revealed that the EM + Avrami maintained good predictions on new (unseen) data. Thus, the enhanced EM + Avrami model may be preferred over the Arrhenius model to predict the flow behavior of Ti6Al4V alloy during industrial forgings, when the initial microstructure is partially equiaxed.

• 出版日期2018-7
• 单位迪肯大学