Abstract The relative density of high-entropy alloys fabricated with selective laser melting (SLM) was enhanced via a process optimization method based on polynomial regression analysis. The resulting alloy exhibited a high relative density (99.71%) and excellent tensile properties (tensile strength = 720 MPa; post-fracture elongation = 31.85%). Optimization has been more commonly based on volumetric energy density (VED), but the unreliability of this method has been evidenced by the large difference in relative densities achieved using the VED-based approach. The high strength of alloy samples was investigated based on structural characterization, and the formation mechanisms of various defects are discussed. There is no micro-segregation or secondary phase according to both theoretical calculations and experimental observation. The strengthening mechanism of SLM FeCoCrNi sample has been reported by quantitative analysis of dislocation strengthening and fine grain strengthening. It was found that the dislocation strengthening contributed more than fine grain strengthening to the increased yield strength in SLM. This deeper insight into the processing and the strengthening mechanisms is expected to contribute to improved mechanical properties of SLM products, thereby increasing the potential for industrial applications of SLM.

中文翻译：

---

激光选区熔化法制备的FeCoCrNi高熵合金的结构和力学性能

摘要 通过基于多项式回归分析的工艺优化方法，提高了选区激光熔化（SLM）制造的高熵合金的相对密度。所得合金表现出较高的相对密度 (99.71%) 和优异的拉伸性能（拉伸强度 = 720 MPa；断裂后伸长率 = 31.85%）。优化更普遍地基于体积能量密度 (VED)，但使用基于 VED 的方法实现的相对密度的巨大差异证明了这种方法的不可靠性。基于结构表征研究了合金样品的高强度，并讨论了各种缺陷的形成机制。根据理论计算和实验观察，不存在微偏析或第二相。通过位错强化和细晶强化的定量分析，报道了SLM FeCoCrNi试样的强化机制。结果表明，位错强化比细晶强化对 SLM 屈服强度的提高贡献更大。对加工和强化机制的深入了解有望有助于提高 SLM 产品的机械性能，从而增加 SLM 工业应用的潜力。