Effect of Strain Rate and Temperature on the Dynamic Tensile Behavior and Constitutive Model of TC21 Titanium Alloy

The dynamic tensile behavior of a newly developed Ti-6Al-2Sn-2Zr-3Mo-lCr-2Nb-Si alloy (referred as TC21) over a wide range of strain rates from quasi-static to dynamic regimes (0.001 similar to 1200 s(-1)) at different temperatures were experimentally investigated. Split Hopkinson tension bar apparatus and a static material testing system were employed to obtain the stress-strain response under uniaxial tension loading condition. The results indicate that the tensile behavior of TC21 titanium alloy is dependent on the strain rate and temperature. The initial yield stress increases with the strain rate increasing. The effects of strain rate and temperature on the initial yield behavior were studied by introducing two rate sensitivity parameters. The phenomenologically based constitutive model (Johnson-Cook model) was suitably modified to describe the dynamic tensile behavior of TC21 titanium alloy. The predicted results of the modified model are in good agreement with the experimental data in the investigating range of strain rates and temperatures.