Dynamic Mechanical Properties and Modified Material Constitutive Model for Hot Forged TiAlNb over Wide Ranges of Temperature and Strain Rate.

In this paper, the stress-strain curves of TiAlNb are established based on uniaxial impact tests over wide ranges of temperature and strain rate. The TiAlNb exhibited the work hardening effect but did not show an obvious yield stage during a quasi-static compression test. In the SHPB test, an obvious temperature softening effect was found, the strain rate strengthening effect was detected when the strain rate was 4000-8000 s, and the strain rate softening effect was detected in the range of 8000-12,000 s. A function describing the effect of strain rate on the strain rate strengthening parameters under various temperatures was proposed to modify the basic J-C constitutive model. The relative errors between the experimental measured value and predicted values in various experimental conditions with a modified J-C model were less than 5.0%. The results verified that the modified J-C model could accurately describe the dynamic mechanical properties of TiAlNb at high temperatures and strain rates. The research could help to illustrate the cutting mechanism and finite element simulation of TiAlNb alloy.