Microstructural features and excellent compression properties of a novel Al0.7CoCrFeNiTi0.3 high entropy alloy

Abstract A novel as-cast Al0.7CoCrFeNiTi0.3 high entropy alloy was prepared by vacuum arc melting and its microstructure and compression properties were investigated. The alloy has an excellent combination of high strength and large plasticity. The yield strength, fracture strength and compressive plasticity of the alloy at room temperature were as high as 1438 MPa, 2990 MPa, and 37.7%, respectively. The alloy was composed of alternating nano-scale face center cubic (FCC), body center cubic (BCC) and ordered L21 phase. The excellent mechanical properties of the alloy are attributed to the combination of the soft FCC phase and the hard BCC/L21 phase. In addition, the large number of phase interfaces provided by the nano-scale lamellar microstructure and precipitated ordered phase also produce a strengthening effect. The fracture mechanism of the alloy is mainly performed at compound fracture mode.