Synthesis of AlxCoCrFeNi high-entropy alloys by high-gravity combustion from oxides

Abstract

A new method for preparing high-entropy alloys (HEAs), combustion synthesis under high-gravity, is presented in this paper, including several highly-exothermic aluminothermic reactions. The microstructures and mechanical properties of the AlxCoCrFeNi HEAs prepared by the above method were investigated. With the increase of the Al content, the crystal structures evolved from face-centered cubic (FCC) to body-centered cubic (BCC) structures, which was proved to be in line with the previous results. The microstructure is strongly related to the synergistic effect of high gravity and Al contents. Massively-dispersive nano-precipitation had been found in the Al0.75CoCrFeNi alloy. The yield strength increases while the plasticity decreases with the increase of Al in AlxCoCrFeNi alloys. All those results confirmed that the new method was potentially a high-throughput technology, which could greatly shorten the processing period and reduce the energy consumption during the production of high performance materials.