Negative strain rate sensitivity of a Ti-8Al-1Mo-1V alloy with bimodal microstructure under quasi-static compression

Abstract The compression behavior of a Ti-8Al-1Mo-1V alloy with bimodal microstructure has been studied in the strain rate range of 2×10-3 s-1-2×10-1 s-1. The strain rate sensitivity shows a positive-negative-positive changing tendency with increasing strain rate. Moreover, serrated flow behavior was found in the first two changing stages of the strain rate sensitivity. Dynamic strain aging caused by solute atom-dislocation interaction within ultrafine α/α' lamellae is proved to be responsible for the appearance of serrations as well as the negative strain rate sensitivity. The reasons for the other two stages of positive strain rate sensitivity have also been analyzed.