Designing novel AlCoCrNi eutectic high entropy alloys

Based on pseudo-ternary phase diagram and microscopic observation, A(l20.45)Co(10)Cr(10)Ni(59.55), Al17.5Co20Cr20Ni52.5 and A(l16.3)Co(25)Cr(25)Ni(33.7) eutectic high entropy alloy (EHEAs) were designed. The experimental results showed that the designed EHEAs all have uniform alternating BCC/FCC lamellar microstructure. Among them, the as-cast Al17.5Co20Cr20Ni52.5 alloy exhibits better tensile property at room temperature. The ultimate tensile strength and total elongation are 1272 MPa and 14.4%, respectively. We verified that the formation of AlCoCrNi EHEAs is related to the ratio of (Co, Ni) to Al, and proposed a new method to design AlCoCrNi EHEAs by fixing the ratio of (Co, Ni) to Al in the alloy. According to the thermophysical parameters and the ratio of (Co, Ni) to Al of the AlCoCrFeNi EHEAs (FCC/BCC) reported so far, the formation rules of this type of EHEAs were summarized. This can provide useful guidance for future design of the AlCoCrFeNi EHEAs.(C) 2022 Elsevier B.V. All rights reserved.

Automated summary

Based on pseudo-ternary phase diagram and microscopic observation, three eutectic high entropy alloys (EHEAs) with uniform lamellar microstructure were designed. One of the alloys exhibits better tensile property at room temperature. The formation of AlCoCrNi EHEAs was found to be related to the ratio of (Co, Ni) to Al.