Microstructure evolution of additively manufactured CoCrFeNiAl0.4 high-entropy alloy under thermo-mechanical processing

Abstract

The microstructure and texture evolution during thermo-mechanical processing (TMP) and their relationship with the mechanical properties in the non-equiatomic CoCrFeNiAl0.4 high-entropy alloy (HEA) were investigated. In this work, a combination of cold rolling and annealing technology was used to investigate the HEA which has been fabricated by powder plasma arc additive manufacturing (PPA-AM) in the deformed and recrystallized states. Microstructure and texture analysis were performed by electron backscatter diffraction. The mechanical properties were evaluated using static tensile testing. It was substantiated that annealing twins facilitates the transition from the cube texture to the shear texture and has a great influence on the evolution of texture after TMP. Based on the research of CoCrFeNiAl0.4 high-entropy alloy, thermo-mechanical processing under appropriate conditions can increase the work hardening rate, but the work hardening rate is relatively stable under 30%–45% plastic deformation. The correlation during TMP between mechanical properties and work hardening, texture evolution, and recrystallization was discussed.

Keywords

• Thermo-mechanical processing
• Powder plasma arc additive manufacturing
• Work hardening rate
• Texture evolution
• Recrystallization