Electroplasticity in the Al0.6CoCrFeNiMn high entropy alloy subjected to electrically-assisted uniaxial tension

Abstract

Electrically assisted deformation (EAD) was adopted in this work to overcome the shortcomings such as poor formability and easy cracking in the processing of dual-phase the Al0.6CoCrFeNiMn high entropy alloy (HEA) at room temperature. Electroplasticity of the Al0.6CoCrFeNiMn HEA was studied systematically using electrically assisted uniaxial tension. The results showed that pulse current caused the temperature gradient along the tensile direction and the temperatures of the samples increased with the current density. The flow stress decreased, and the elongation increased with increasing current density during the EAD. When the current density was 30 A mm–2, the total elongation of the samples could be increased by 50% compared to that with no pulse. Pulse current can reduce local stress concentration and postpone microcracks initiation in the body-centered cubic (BCC) phases, and hence can effectively inhibit cracks and ruptures. The dislocation tangles were opened by pulse current, and the dislocation recovery was enhanced at a high current density. Compared with dilute solid solution alloys, the lattice distortion effect, the high fraction of the BCC phases, and the dislocations in HEAs can lead to the enhancement of the local Joule heating, which accelerated dislocation slip and dislocation annihilation. This study confirms that EAD can effectively improve the formability of HEAs and provides theoretical guidance and an experimental basis for forming HEAs components.