Abstract In the present work, martensitic stainless steel (MSS) coatings with niobium (Nb) contents of 0–1.0 wt%, combining high strength and ductility with improved corrosion resistance, have been developed and fabricated by a laser cladding technique. The effects of Nb-microalloying on the microstructure and properties of the laser-cladded MSS coatings have been carefully investigated. The results show that the original Nb-free MSS coating is mainly composed of martensite and austenite, along with nano-M2N and M23C6. With the addition of Nb, the lath-shaped martensite is refined, and an increasing occurrence of nano-sized Nb-enriched precipitates (NbC and Nb(C,N)) is observed in the coatings with increasing Nb content. With the successive addition of Nb, the microhardness of the specimens is found to increase from the 437 HV0.2 of the Nb-free coating to the 502 HV0.2 of the 1.0 wt% Nb-alloyed coating. At the same time, the tensile mechanical properties and corrosion resistance are found to increase with increasing Nb content of up to 0.5 wt% and subsequently decrease with further addition of Nb. Thus, the addition of 0.5 wt% Nb provides a laser-cladded MSS coating that is superior to those reported in the literature, combining the optimum tensile properties of high strength (1780 MPa) and high ductility (EL = 10.5%) along with excellent corrosion resistance. The remarkable overall properties of the as-prepared MSS coatings can be ascribed to the combined effects of solid solution, microstructural refinement, and nano-precipitation.

中文翻译：

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激光熔覆高强度韧性马氏体不锈钢加铌涂层的研制

摘要 在目前的工作中，采用激光熔覆技术开发和制造了铌 (Nb) 含量为 0-1.0 wt% 的马氏体不锈钢 (MSS) 涂层，结合了高强度和延展性以及提高的耐腐蚀性。已经仔细研究了 Nb 微合金化对激光熔覆 MSS 涂层的微观结构和性能的影响。结果表明，原始的无 Nb MSS 涂层主要由马氏体和奥氏体组成，以及纳米 M2N 和 M23C6。随着Nb的加入，板条状马氏体被细化，随着Nb含量的增加，在涂层中观察到纳米级富Nb析出物（NbC和Nb（C，N））的出现增加。随着 Nb 的连续添加，发现试样的显微硬度从 437 HV0 增加。2 无 Nb 涂层与 1.0 wt% Nb 合金涂层的 502 HV0.2。同时，发现拉伸机械性能和耐腐蚀性能随着 Nb 含量的增加而增加至 0.5 wt%，随后随着 Nb 的进一步添加而降低。因此，添加 0.5 wt% Nb 提供了优于文献报道的激光熔覆 MSS 涂层，结合了高强度 (1780 MPa) 和高延展性 (EL = 10.5%) 的最佳拉伸性能以及优异的耐腐蚀性能。所制备的 MSS 涂层显着的整体性能可归因于固溶、微观结构细化和纳米沉淀的综合作用。发现拉伸机械性能和耐腐蚀性能随着 Nb 含量的增加而增加至 0.5 wt%，随后随着 Nb 的进一步添加而降低。因此，添加 0.5 wt% Nb 提供了优于文献报道的激光熔覆 MSS 涂层，结合了高强度 (1780 MPa) 和高延展性 (EL = 10.5%) 的最佳拉伸性能以及优异的耐腐蚀性能。所制备的 MSS 涂层的显着整体性能可归因于固溶体、微观结构细化和纳米沉淀的综合作用。发现拉伸机械性能和耐腐蚀性能随着 Nb 含量的增加而增加至 0.5 wt%，随后随着 Nb 的进一步添加而降低。因此，添加 0.5 wt% Nb 提供了优于文献报道的激光熔覆 MSS 涂层，结合了高强度 (1780 MPa) 和高延展性 (EL = 10.5%) 的最佳拉伸性能以及优异的耐腐蚀性能。所制备的 MSS 涂层的显着整体性能可归因于固溶体、微观结构细化和纳米沉淀的综合作用。5 wt% Nb 提供了优于文献报道的激光熔覆 MSS 涂层，结合了高强度 (1780 MPa) 和高延展性 (EL = 10.5%) 的最佳拉伸性能以及优异的耐腐蚀性。所制备的 MSS 涂层的显着整体性能可归因于固溶体、微观结构细化和纳米沉淀的综合作用。5 wt% Nb 提供了优于文献报道的激光熔覆 MSS 涂层，结合了高强度 (1780 MPa) 和高延展性 (EL = 10.5%) 的最佳拉伸性能以及优异的耐腐蚀性。所制备的 MSS 涂层的显着整体性能可归因于固溶体、微观结构细化和纳米沉淀的综合作用。