On temperature and strain-rate dependence of flow serration in HfNbTaTiZr high-entropy alloy

Abstract

Plastic instability manifested as the serrated flow on stress-strain curves of metal alloys is generally detrimental to their processing and manufacturing. The flow serration in the HfNbTaTiZr alloy is reported in the present work and its dependence on temperatures (573-823K) and strain rates (5 × 10−5 s−1-1 × 10−3 s−1) is investigated with experiments. The notable transition of the onset strain of the serrated flow from a declining (normal behavior) to rising (inverse behavior) trend with increasing temperature at applied strain rates is modeled successfully with a theoretical framework. The success of the model in predicting the onset strain as a function of temperature and strain rate represents a possibility of theoretically constructing a process window for the alloy under examination and beyond.