Trade-off between tensile property and formability by partial recrystallization of CrMnFeCoNi high-entropy alloy

In this work, a high-entropy alloy of equiatomic CrMnFeCoNi was processed by vacuum induction melting followed by rolling. After cold rolling, annealing for one hour was conducted during which the annealing temperature was varied from 650 to 1000 °C. This was done to investigate the effect of microstructure on tensile properties and stretch formability (defined as the capability of materials to undergo plastic deformation under biaxial stretching). The strengthening effect of partial recrystallization, with a remaining small fraction of sigma phase particles, led to improved yield and tensile strengths while minimizing the loss of ductility. Fully recrystallized microstructure resulted in a slight increase in ductility, and a considerable decrease in strength, during a tensile test. On the other hand, the results for stretch formability suggest that partial recrystallization had exactly the opposite results. In this regard, the present results raise a new issue to consider when utilizing partial recrystallization for improvement of mechanical properties.