To widen the applications of new materials in additive manufacturing (AM), the traditional method of printing using pre-alloyed powders should be improved because the pre-alloying process is expensive and makes it difficult to adjust the composition of new materials. This study investigates the synthesis of a FeCoCrNi high-entropy alloy (HEA) containing 1.5 at.% Si in situ using selective laser melting (SLM). A remelting strategy and process optimization based on polynomial regression modeling allowed for the printing of almost fully dense (99.78 %) samples. The samples comprised columnar grains, each containing numerous subgrains of a single-phase face-centered cubic solid solution. No precipitation or segregation were observed. The room temperature tensile properties of the samples were excellent, with yields and tensile strengths reaching 701 ± 14 and 907 ± 25 MPa, respectively, and an elongation at fracture of 30.8 ± 2%. These properties were attributed to solid solution strengthening and novel dislocation loop strengthening mechanism. These findings demonstrate that HEAs with a high relative density and good mechanical properties can be directly synthesized by SLM using inexpensive pure metal powders, thereby extending the application potential of AM to manufacture new materials.

为了拓宽新材料在增材制造（AM）中的应用，应改进使用预合金粉末的传统印刷方法，因为预合金化过程价格昂贵并且难以调整新材料的成分。这项研究调查了原位含1.5at。％Si的FeCoCrNi高熵合金（HEA）的合成使用选择性激光熔化（SLM）。基于多项式回归模型的重熔策略和工艺优化可打印几乎完全稠密（99.78％）的样品。样品包含柱状晶粒，每个晶粒包含许多单相以面心为中心的立方固溶体的亚晶粒。没有观察到沉淀或偏析。样品的室温拉伸性能极好，屈服强度和拉伸强度分别达到701±14和907±25 MPa，断裂伸长率为30.8±2％。这些性质归因于固溶强化和新型位错环强化机制。这些发现表明，具有高相对密度和良好机械性能的HEA可以通过SLM使用廉价的纯金属粉末直接合成，