Modeling the hot working behavior of near-α titanium alloy IMI 834

Abstract

The hot working behavior of near-α titanium alloy IMI 834 with a duplex starting microstructure was studied using the technique of processing map. The processing map was interpreted in terms of the microstructural processes occurring during deformation, based on the values of dimensionless parameter η which represents the energy dissipation through microstructural processes. An instability criterion (ξ<0) was also applied to demarcate the flow instability regions in the processing map. Both the parameters (η and ξ) were computed using the experimental data generated by carrying out hot compression tests over a range of temperatures (850–1060°C) and strain rates (3×10−4−1/s). The deterministic domains observed under the investigated temperature and strain rate conditions were attributed to continuous dynamic recrystallization or globularisation of α lamellae, dynamic recrystallization and growth of β grains through microstructural observations. An unified strain compensated constitutive equation was established to describe the hot working behavior of the material in the selected temperature–strain rate range. The established constitutive equation was validated using standard statistical parameters such as correlation coefficient and average absolute relative error.