Microstructure evolution and mechanical properties of Al0.4CoFeNiTi0.6 dual-phase high entropy alloy

Abstract

The influence of annealing treatment on the microstructure evolution and mechanical properties of a new multi-principal component high entropy alloy (HEA) with dual-phase, Al0.4CoFeNiTi0.6, prepared by arc-melting, was investigated in detail. The as-cast alloy was composed of simple BCC and FCC phases which were further confirmed to be B2 and L12 structures. The yield strength (σ0.2), fracture strength and plastic strain of the as-cast alloy are 2085 MPa, 2136 MPa and 10.3%, respectively. Following annealing treatment, a large number of shortly rod-like phases are precipitated from the ordered BCC phase. The as-annealed alloy projects a decrease of ~33% in yield strength and a decrease of ~8% in fracture strength. However, the plastic strain is increased from 10.3 to 21%. The hardness increased from 467 HV to 548 HV, indicating that the alloy exhibits excellent temper-resistant softening properties.