Effect of Heat Treatment and Melting Method Changing on AlCoCrFeNiTi0.2 High Entropy Alloy

The AlCoCrFeNiTi0.2 alloy was designed and prepared by the arc melting method. Results show that formed the B2 phase and the bcc phase form in the as-cast alloy, and it shows 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 6000 MPa. After heat-treatment at 550, 800 and 1050 degrees C followed by water cooling, the phase composition corresponding to the three temperatures is bcc+B2, bcc+B2+fcc+sigma, and bcc+B2+fcc, respectively. The brittleness and hardness of the alloy increase after heat treatment. A bulk AlCoCrFeNiTi0.2 alloy was prepared by magnetic levitation melting. The alloy has a relatively uniform composition distribution, forming a bcc+B2+sigma three-phase structure. The compressive plasticity is 35.0% at 600 degrees C while still maintains a yield strength of 1486.7 MPa, suggesting good high temperature performance.