Physically based model for plasticity and creep of Ti-6Al-4V

Abstract: Albeit Ti-6Al-4V has numerous salient properties, its usage for certain applications is limited due to the challenges faced during manufacturing. Understanding the dominant deformation mechanisms and numerically modelling the process is the key to overcome this hurdle. This work investigates plastic deformation of the alloy at strain rates from 0.001/s to 1/s and temperatures between 20 and 1100 Celsius. Pertinent deformation mechanisms of the material when subjected to thermo-mechanical processing is discussed. A physically based constitutive model based on the evolution of immobile dislocation density and excess vacancy concentration is developed. Parameters of the model are obtained by calibration using isothermal compression tests. Model is compared with relaxation test data to demonstrate its validity.