Investigation on dynamic properties and failure mechanisms of Ti-47Al-2Cr-2Nb alloy under uniaxial dynamic compression at a temperature range of 288 K-773 K

Uniaxial compression tests were performed on Ti-47Al-2Cr-2Nb alloy at a temperature range of 288 K-773 K. The mechanical response and microstructure of Ti-47Al-2Cr-2Nb alloy after uniaxial compression were systematically analyzed. Investigation on mechanical properties show that under dynamic compression, the yield strength and ductility of Ti-47Al-2Cr-2Nb alloy remain almost same at all loading temperatures, while the strain hardening rate of the Ti-47Al-2Cr-2Nb alloy present an obvious declining trend with the increased loading temperatures, resulting in the decreasing of ultimate compressive strength. Failure analysis reveals that under quasi-static compression, the failure mechanism of Ti-47Al-2Cr-2Nb alloy is micro-porous coalescence failure in α₂ phases. Under dynamic compression at a temperature range of 288-773 K, shear failure is the main failure mode of Ti-47Al-2Cr-2Nb alloy. It is interesting to find that at a temperature range of 288 K-373 K, the failure mechanism of Ti-47Al-2Cr-2Nb alloy is brittle shear failure owing to the rapid propagation of micro-cracks along the lamella interface. When the loading temperature increases over 473 K, adiabatic shear band (ASB) is observed, indicating that the failure mechanism of Ti-47Al-2Cr-2Nb alloy transfers from brittle shear failure to adiabatic shear failure.