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 Al_(0.6) CoCrFeNiMn high entropy al-loy(HEA)at...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 Al_(0.6) CoCrFeNiMn high entropy al-loy(HEA)at room temperature.Electroplasticity of the Al_(0.6) CoCrFeNiMn 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 den-sity.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 post-pone 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 con-firms that EAD can effectively im prove the formability of HEAs and provides theoretical guidance and an experimental basis for forming HEAs components.展开更多
基金financially supported by the National Natural Science Foundation of China(No.51635005)the National Re-search Foundation of Korea(NRF)grant funded by the Korea gov-ernment(MSIP)(No.NRF-2021R1A2C3006662)supported by the China Scholarship Council(CSC,No.202106120151).
文摘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 Al_(0.6) CoCrFeNiMn high entropy al-loy(HEA)at room temperature.Electroplasticity of the Al_(0.6) CoCrFeNiMn 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 den-sity.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 post-pone 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 con-firms that EAD can effectively im prove the formability of HEAs and provides theoretical guidance and an experimental basis for forming HEAs components.
