A novel high-entropy alloy with excellent damping property toward a large strain amplitude environment

A new Fe60Mn20Co5Cr15 high-entropy alloy with excellent damping performance was synthesized by mechanical alloying (MA) and spark plasma sintering (SPS). During SPS, the supersaturated solid solution produced in MA was transformed into a stable microstructure consisting of body-centered cubic (BCC) phase, face-centered cubic (FCC) phase and small amount of σ phase. The effects of different annealing temperature on phase evolution, microstructure, mechanical properties and damping behavior were investigated. The results of compressive properties indicated a reduction in strength but an increase in plastic strain when the alloy was annealed at high temperature. Compared with the SPSed bulk, the damping properties were improved significantly by the annealing process, which was related to the number of defects and the morphology of magnetic domains. For the samples annealed at 900 °C, a maximum of internal friction (IF) Q−1 = 0.076 was achieved and the corresponding strain amplitude was approximately 6×10−4, overwhelming the conventional damping alloys. Besides, a high damping capability of the alloy can be achieved in a wider strain range, which means that it can act as a promising candidate toward a larger strain amplitude environment.