Enhancement of mechanical properties of a novel single phase Ni1.5FeCrCu0.5 HEA through cold rolling and subsequent annealing

Abstract

A novel single-phase Ni1.5FeCrCu0.5 High entropy alloy was fabricated by Vacuum Arc Remelting (VAR). The evolution of the alloy's microstructures, crystallographic texture, and mechanical behavior was investigated in as-cast, cold rolling (90% thickness reduction), and annealing (1000 °C for 1 h) conditions. Microstructural evolution demonstrated that the dendritic structure of the as-cast HEA was associated with a very small amount of Cu element segregation, which changed to tense elongated grains after cold rolling. Cold rolling resulted in development of Goss {110}<001>, Goss/Brass {110}<111> and Brass {110}<112> as the major texture components. After annealing, the complete recrystallization structure appeared in an average grain size of 3 μm, and deformation texture components remained. The results indicated the cold rolling led to a significant strengthening of the alloy; its yield strength and ultimate tensile strength of the alloy reached 1220 and 1574 MPa, which was 5 and 3.5 times the as-cast conditions (yield strength: 236 MPa and ultimate tensile strength: 454 MPa), respectively. However, the elongation was reduced to 5%. Eventually, the elongation in the recrystallization state increased approximately seven times.