Abstract Al0.7CoCrFeNi high-entropy alloy (HEA), as a promising material, has attracted growing interest. This study aimed to investigate the effect of phase transformation in non-equilibrium Al0.7CoCrFeNi HEA on its properties and densification kinetics during spark plasma sintering (SPS). We found that the BCC-to-FCC phase transformation causes a grain size reduction from 5.66 to 3.10 μm, while decreases the Vickers hardness from 372.5 ± 4 to 328.4 ± 3 HV. The decreased Vickers hardness reduces the wear resistance with the volume wear rate increasing from 1.583 × 10−4 to 2.108 × 10−4 mm3·N−1·m−1. Besides, the BCC-to-FCC phase transformation improves the ductility from 2.5 ± 0.4 to 8.4 ± 0.3%. The further precipitation of a θ phase observed in the sample sintered at 1100 °C improves the ultimate tensile strength from 856.1 ± 13 to 1053.7 ± 8 MPa, although the ductility decreases from 8.4 ± 0.3 to 7.3 ± 0.3%. Interestingly, we also observed that the BCC-to-FCC phase transformation reduces densification kinetics, because it decreases the diffusion coefficient.

中文翻译：

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相变对放电等离子烧结Al0.7CoCrFeNi高熵合金致密化动力学和性能的影响

摘要 Al0.7CoCrFeNi 高熵合金（HEA）作为一种很有前途的材料，引起了越来越多的关注。本研究旨在研究非平衡 Al0.7CoCrFeNi HEA 中的相变对其性质和放电等离子体烧结 (SPS) 过程中致密化动力学的影响。我们发现 BCC 到 FCC 相变导致晶粒尺寸从 5.66 减小到 3.10 μm，同时将维氏硬度从 372.5 ± 4 降低到 328.4 ± 3 HV。降低的维氏硬度降低了耐磨性，体积磨损率从 1.583 × 10-4 增加到 2.108 × 10-4 mm3·N-1·m-1。此外，BCC-to-FCC 相变将延展性从 2.5±0.4% 提高到 8.4±0.3%。在 1100°C 烧结的样品中观察到的 θ 相的进一步沉淀将极限抗拉强度从 856.1 ± 13 MPa 提高到 1053.7 ± 8 MPa，尽管延展性从 8.4 ± 0.3 下降到 7.3 ± 0.3%。有趣的是，我们还观察到 BCC 到 FCC 的相变降低了致密化动力学，因为它降低了扩散系数。