Dynamic Tensile Behavior and Constitutive Modeling of TC21 Titanium Alloy

Abstract

The dynamic tensile behaviors of a newly developed Ti-6Al-2Sn-2Zr-3Mo-1Cr-2Nb-Si alloy (referred as TC21 in China) over a wide range of strain rates from quasi-static to dynamic regimes (0.001–1 200 s⁻¹) at different temperatures were experimentally investigated. A split Hopkinson tension bar apparatus and a static material testing system were utilized to study the stress-strain responses under uniaxial tension loading condition. The experimental results indicate that the tensile behavior of TC21 titanium alloy is dependent on the strain rate and temperature. The values of initial yield stress increase with increasing strain rate and decreasing temperature. The effects of strain rate and temperature on the initial yield behavior are estimated by introducing two sensitivity parameters. The phenomenological-based constitutive model, Johnson-Cook model, is suitably modified to describe the rate-temperature dependent constitutive behavior of TC21 titanium alloy. It is observed that the modified model is in good agreement with the experimental data subjected to the investigated range of strain rates and temperatures.

Keywords

two-phase titanium alloy / dynamic tensile behavior / rate-temperature sensitivity / constitutive modeling