Dynamic strain-rate effect on uniaxial tension deformation of Ti5Al2.5Sn α-titanium alloy at various temperatures

Abstract

ABSTRACTThe uniaxial tensile experiments for Ti5Al2.5Sn alloy were performed at strain rates ranging from 10−3–10+3 s−1 and test temperatures of 153–873 K. Experimentally measured stress-strain responses indicate the yield strength exhibits positive strain-rate dependency, while the yield strength increases as the test temperature is decreased. To understand the thermomechanical coupling of dynamic plastic deformation, a specially developed single-tensile-pulse loading technique was used, and the isothermal stress-strain curves for the rates of 180 and 450 s−1 were obtained at temperatures of 203, 298 and 573 K. The plastic strain hardening measurements obtained here are essentially athermal and largely independent of strain rate, consistent with titanium and its alloys being bcc-structure-like in mechanical behaviour. Based on the experimentally obtained plastic deformation features of the alloy, the physically based Voyiadjis-Abed constitutive relationship was modified to model the dynamic tensile deformation of the Ti5Al2.5Sn alloy at low and high temperatures.