We produced a sub-millimeter-order periodic laminate structure exhibiting different hardness values, phase constituents, and microstructures for an AISI H13 hot work tool steel using a selective laser melting (SLM) process under a combination of different processing conditions applied periodically and continuously (under the concept of “scan strategy”). SLM-scanning with a high energy input beam, which was periodically inserted once every 1.5 mm in the building direction in combination with a low energy input, results in the formation of deep quench-hardened areas and produces a laminate structure possessing different hardness distributions. The surface area (corresponding to the top area) of the SLM product consists of untempered hard martensite because of the rapid cooling of the final heated layer. The local hardened area (corresponding to the intermediate area) and the surrounding area (corresponding to the matrix area) are subjected to tempering due to subsequent reheating to different degrees during the SLM process. Microstructures in all the regions of the top, intermediate, and matrix areas in the laminate structure consist of α'-martensite and austenite (γ) phases. A large amount of retained austenite is also present in the matrix area. The difference in hardness, depending on the area in the laminate structure, is caused by the difference in dislocation densities (related to the degree of tempering depending on the area) and the different amounts of retained austenite. Thus, the results of this study suggest a methodology as well as optimum SLM process conditions (by the “scan strategy”) for producing the laminate structure by controlling the difference in the degree of tempering and altering the Vickers hardness.

我们使用选择性激光熔化 (SLM) 工艺，在周期性和连续应用的不同加工条件的组合下，为 AISI H13 热作工具钢生产了一种亚毫米级周期性层压结构，该结构具有不同的硬度值、相成分和微观结构。在“扫描策略”的概念下）。使用高能量输入光束的 SLM 扫描，在构建方向上每隔 1.5 毫米周期性插入一次，结合低能量输入，导致形成深淬火硬化区域并产生具有不同硬度分布的层状结构。由于最终加热层的快速冷却，SLM 产品的表面积（对应于顶部区域）由未回火的硬质马氏体组成。局部硬化区（对应中间区）和周边区域（对应基体区）由于后续在SLM过程中不同程度的再加热而进行回火。层状结构中顶部、中间和基体区域的所有区域的显微组织由α'-马氏体和奥氏体（γ）相组成。基体区也存在大量残余奥氏体。硬度的差异，取决于层状结构中的面积，是由位错密度的差异（取决于面积的回火程度）和残余奥氏体量的不同引起的。因此，