Effect of heating rate on microstructure and mechanical properties of AlCoCrFeNi high entropy alloy produced by spark plasma sintering

Spark plasma sintering (SPS), as a novel powder consolidation method, has great potential in the production of high entropy alloys (HEAs). The heating rate is an important parameter in SPS, and understanding its effect is a critical issue for the purpose to optimize microstructure and promote mechanical properties of HEAs. The AlCoCrFeNi was adopted as a representative HEA in this study. The phase compositions, microstructural textures, and mechanical properties were investigated in this study in detail. It was found that the FCC phase formed at BCC grain boundaries while the σ phase precipitated at the interface of B2/BCC no matter of the heating rate. The texture varied at different heating rates as the texture {110}<755> in B2/BCC was characterized at the heating rate of 150 °C/min while the complex texture {051}<715> in FCC was observed at the heating rate of 200 °C/min. The Vickers hardness and wear resistance decreased with increasing of the heating rate. Furthermore, the compressive strength and corresponding plastic strain reached their highest 2752.0 ± 48 MPa and 26.5 ± 1.3% at the heating rate of 150 °C/min.