Constitutive modeling of dynamic strain aging for HCP metals

Dynamic strain aging hugely affects the microstructural mechanical behavior of metallic materials when activated. It has been extensively reported in the literature that the dynamic strain aging causes significant gaps between model predictions and experimental measurements. Without considering this phenomenon, a constitutive model is unable to accurately capture the material behavior when it is active. The new constitutive model for hexagonal close-packed metals is developed in this work to predict the dynamic strain aging-induced hardening based on the probability function. The proposed model consists of three elements, i.e. dynamic strain aging-induced flow stress as well as thermal and athermal flow stresses. Physically motivated derivation of all the three elements is presented. The proposed model is applied to pure hexagonal close-packed titanium under quasi-static loading ((epsilon) over dot = 0.001/s and (epsilon) over dot = 0.1/s) to dynamic loading ((epsilon) over dot = 2200/s and (epsilon) over dot = 8000/s) across a broad range of temperatures (77 1000 K).