The microstructure and corrosion resistance of FeCrCuTiV high entropy alloy prepared by vacuum arc melting and laser melting deposition were studied. The microstructure and phase composition of FeCrCuTiV high entropy alloy were characterized by SEM, XRD, EBSD, etc. It is found that both of them are composed of the FCC Cu-rich phase, BCC Fe-rich phase and, BCC V-rich phase. Comparing with FeCrCuTiV high entropy alloy prepared by vacuum arc melting, the grain size of FeCrCuTiV high entropy alloy prepared by the laser melting deposition reduces from 29.48 µm to 1.85 µm. Meanwhile, the Cu-rich phase volume fraction decreases from 44.7 % to 31.5 %. Two reasons contribute to this phenomenon: On the one hand, the higher cooling rate of high entropy alloy makes the grain growth limited and the grain size reduced. On the other hand, the higher cooling rate reduces the volume fraction of intergranular segregation Cu-rich phase formed under non-uniform solidification due to the lack of long-range migration of Cu element, which makes the solidification state of FeCrCuTiV high entropy alloy prepared by laser melting deposition deviate from the ideal thermodynamic equilibrium. In addition, the corrosion resistance test of FeCrCuTiV high entropy alloy prepared by two processes indicates: FeCrCuTiV high entropy alloy prepared by laser melting deposition shows better corrosion resistance under the electrochemical corrosion of salt solution. This result is caused by the reduction of the Cu-rich phase, which weakens its corrosion effect as the anode of galvanic cell. Laser melting deposition technology provides new ideas and methods for controlling the phase structure of complex solid solution high entropy alloys to improve their physical properties.

中文翻译：

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不同工艺制备FeCrCuTiV两相高熵合金的显微组织形成机制及腐蚀行为

研究了真空电弧熔炼和激光熔化沉积制备的FeCrCuTiV高熵合金的显微组织和耐蚀性能。采用SEM、XRD、EBSD等对FeCrCuTiV高熵合金的显微组织和相组成进行表征，发现它们均由FCC富Cu相、BCC富Fe相和BCC富V相组成。 。与真空电弧熔炼制备的FeCrCuTiV高熵合金相比，激光熔融沉积制备的FeCrCuTiV高熵合金的晶粒尺寸由29.48μm减小到1.85μm。同时，富Cu相体积分数从44.7%下降到31.5%。造成这种现象的原因有两个：一方面，高熵合金较高的冷却速率使得晶粒长大受到限制，晶粒尺寸减小。另一方面，较高的冷却速率降低了由于Cu元素缺乏长程迁移而在非均匀凝固下形成的晶间偏析富Cu相的体积分数，这使得制备的FeCrCuTiV高熵合金的凝固状态通过激光熔化沉积偏离理想的热力学平衡。另外，对两种工艺制备的FeCrCuTiV高熵合金的耐腐蚀性能测试表明：激光熔融沉积制备的FeCrCuTiV高熵合金在盐溶液电化学腐蚀下表现出更好的耐腐蚀性能。这一结果是由于富Cu相的减少导致其作为原电池阳极的腐蚀作用减弱所致。激光熔化沉积技术为控制复杂固溶体高熵合金的相结构、改善其物理性能提供了新的思路和方法。