Adiabatic shear band localization in an Al–Zn–Mg–Cu alloy under high strain rate compression

Abstract

An investigation was conducted to study the effect of high strain rate compression on the microstructure and mechanical properties of a spray deposited and hot formed by forging and extrusion followed by T74 (393 K/8h + 433 K/24 h) heat treatment Al–Zn–Mg–Cu alloy. The results show that the strength of the Al alloy is increased with increasing strain rate from 1.0 × 10−3 s−1 to 5.0 × 103 s−1 assisted by the strain hardening rate effect. Typical adiabatic shear bands area is found in the Al–Zn–Mg–Cu alloy after compression at high strain rate. Grains are significantly refined within the shear bands areas to ∼180 nm assisted by the dislocation accumulation combined with the temperature rise during the high strain rate compression. Precipitates are observed within the shear bands mainly of fine η' precipitates. These precipitates are close to Mg (Zn, Cu, Al)2 assisted by diffusion provided by dislocations.

Keywords

• Adiabatic shear bands
• Al–Zn–Mg–Cu alloy
• High strain rate
• Precipitates