Study on Mechanical Properties and Impact-Induced Energy Release Characteristics Of TiZrTaNbHf High Entropy Alloy

Abstract

High entropy alloys are known for their ability to release energy under impact, it can be used as an energetic structural material. To investigate the ignition performance of TiZrTaNbHf alloy under impact load and deformation behavior at different strain rates, the mechanical properties of TiZrTaNbHf alloy were tested using a universal material testing machine and a separated Hopkinson pressure bar experimental system. The energy release process of TiZrTaNbHf alloy samples under dynamic impact load was recorded by high-speed photography, and the energy release behavior and ignition mechanism of TiZrTaNbHf alloy under dynamic impact load was investigated. The results show that the yield strength of TiZrTaNbHf alloy under static compression is 1190MPa, while the yield strength of TiZrTaNbHf alloy under high strain rate (strain rate is 2200s-1~3500s-1) is 1673MPa~1732MPa, which is increased by 40%~45% compared with quasi-static compressive strength. When the strain rate increases to a certain range, the stress collapse of the alloy sample occurs, leading to the plasticity of the sample decrease greatly. When TiZrTaNbHf alloy sample is subjected to impact load, the sample undergoes compression shear failure, and the temperature rise generated by shear and friction causes the cross-section of the alloy sample to react with oxygen in the air, releasing a large amount of heat. The energy release phenomenon of TiZrTaNbHf alloy will increase with the increase of strain rate.

Keywords: high entropy alloys, Mechanical properties, Impact-induced energy release