Effect of strain rate on the tension behavior of Ti–6.6Al–3.3Mo–1.8Zr–0.29Si alloy at low temperatures

Abstract

The tension responses of Ti–6.6Al–3.3Mo–1.8Zr–0.29Si are investigated over a broad range of strain rates, 0.001–1150s−1, and initial temperatures, 213–293K. Tensile impact and recovery tests are carried out using the split Hopkinson tension bar technique to obtain the adiabatic and isothermal stress–strain behavior of the alloy at high strain rates. Experimental results indicate that the tension behavior of the alloy is dependent on the strain rate and temperature. The value of initial yield stress increases with increasing strain rate and decreasing temperature. The isothermal strain hardening behavior changes little at different strain rates and temperatures. The adiabatic temperature rise is the main reason for the reduction of strain hardening rate during the high-rate deformation process. SEM observations of the fracture surfaces indicate that the tension specimen is broken in a manner of ductile fracture. The Zerilli–Armstrong constitutive model incorporating the effect of thermal–mechanical coupling is used to describe the rate and temperature dependent deformation behavior of Ti–6.6Al–3.3Mo–1.8Zr–0.29Si alloy. The model results are very close to the experimental data within the tested range of strain rates and temperatures.