High temperature tribological performance of a cost-effective eutectic high entropy alloy Al0.8CrFeNi2.2: Comparison with AlCoCrFeNi2.1

A comprehensive comparison study on microstructure, mechanical and high temperature tribological perfor-mance of as-cast Al0.8CrFeNi2.2 and AlCoCrFeNi2.1 eutectic high entropy alloys was conducted. The cost-effective Al0.8CrFeNi2.2 exhibited higher hardness and tensile strength than AlCoCrFeNi2.1. AlCoCrFeNi2.1 showed better friction and wear performances than Al0.8CrFeNi2.2 at RT, but an opposite trend was observed when temperature exceeded 300 oC. Higher Ni content in FCC and BCC(B2) phases of Al0.8CrFeNi2.2 are found to increase the hardness of constitution phases. The tribolayers of Al0.8CrFeNi2.2 at 900 oC composes of distinguished oxide layer and ultrafine-grained particles layer, which are different from the mixing pattern in AlCoCrFeNi2.1. A relatively thicker tribo-layer is also found to enhance the high temperature tribological properties of Al0.8CrFeNi2.2.

Automated summary

A comparison study was conducted on the microstructure, mechanical properties and high temperature tribological performance of as-cast Al0.8CrFeNi2.2 and AlCoCrFeNi2.1 eutectic high entropy alloys. The cost-effective Al0.8CrFeNi2.2 exhibited higher hardness and tensile strength compared to AlCoCrFeNi2.1. While AlCoCrFeNi2.1 showed better friction and wear performance at room temperature, the opposite trend was observed at temperatures exceeding 300°C. The higher Ni content in FCC and BCC(B2) phases of Al0.8CrFeNi2.2 increased the hardness of constituent phases. The tribolayers of Al0.8CrFeNi2.2 at 900°C consisted of a distinct oxide layer and ultrafine-grained particle layer, which differed from the mixing pattern in AlCoCrFeNi2.1. A thicker tribolayer was also found to enhance the high temperature tribological properties of Al0.8CrFeNi2.2.