Effect of copper on microstructural evolution and mechanical properties of laser-welded CoCrFeNi high entropy alloy

In this work, laser welding of CoCrFeNi and CoCrCuFeNi HEA was carried out. X-ray diffraction, electron backscattered diffraction, mechanical property and microstructural analyses were performed. In CoCrFeNi alloy, a face centred cubic (FCC) structure was observed in both base metal and laser-welded conditions. The addition of Cu in CoCrFeNi alloy is resulted in two FCC phases and has increased the tensile strength from 593 to 666 MPa. The fusion zone of both the welds shows coarser columnar grain and lower hardness compared to that of base metals. Post-welding results show 53% decrease in tensile strength in the alloy containing Cu (CoCrFeNiCu). Whereas only a marginal decrease in strength is observed in CoCrFeNi alloy.

Automated summary

In this study, laser welding of CoCrFeNi and CoCrCuFeNi alloys was conducted. It was found that the addition of Cu resulted in changes in the microstructure and mechanical properties of the alloys. The fusion zone of both the welds exhibited coarser grains and lower hardness compared to the base metals.