Dynamic precipitation at elevated temperatures in a dual-phase AlCoCrFeNi high-entropy alloy: an in situ study

Abstract

The effect of a possible phase transformation or precipitation of the face-centred cubic (FCC) phase on intermediate-temperature deformation of a dual-phase AlCoCrFeNi high-entropy alloy has been studied using in situ tensile testing at 550°C. Electron backscatter diffraction (EBSD) results showed localised precipitation of the FCC phase during the intermediate-temperature deformation. The overall fracture behaviour and crack propagation of the material was not altered much compared to the room-temperature behaviour, namely brittle trans-granular fracture. Deformation at higher temperatures (above 750°C) is suggested as a way to enhance the dynamic FCC phase precipitation, in order to improve the ductility or deformability of the alloy.