Effect of heat treatment and melting method changing on AlCoCrFeNiTi0.2 high entropy alloy

Abstract:

The AlCoCrFeNiTi_0.2 alloy was designed and prepared by the arc melting method. It was found that the as-cast alloy formed the B2 phase and the BCC phase, and showed good room temperature compressibility, compressive plasticity of 32.6%, yield strength of 1530.4 MPa, and compressive strength of 4035.0 MPa. The hardness is about 600 HV. It was heat-treated at 550°C, 800°C and 1050°C, and the high-temperature phase was preserved by water cooling. The phase composition corresponding to the three temperatures was BCC + B2, BCC + B2 + FCC + σ, and BCC + B2 + FCC. The brittleness and hardness of the alloy increase after heat treatment. A bulk AlCoCrFeNiTi_0.2 alloy was prepared by magnetic levitation melting. The alloy has a relatively uniform composition distribution, forming a BCC + B2 + σ three-phase structure. The compressive plasticity is 35.0% at 600°C, and it can still maintain a yield strength of 1486.7 MPa which is good at high temperature.