沈阳工业大学学报2025，Vol.47Issue(3)：332-338,7.DOI:10.7688/j.issn.1000-1646.2025.03.09
合金元素Nb对激光熔覆铁基合金组织及性能的影响
Effect of alloying element Nb on microstructure and properties of Fe-based alloy prepared by laser cladding
摘要
Abstract
[Objective]Martensitic stainless steel(0Cr13Ni5Mo)has good forging,casting,and corrosion resistance performance and is therefore widely used in hydropower,chemical industry,and high-pressure vessels.However,the special working environment can accelerate failure of the 0Cr13Ni5Mo material,especially for hydraulic flow passage components which are subjected to sand impact and corrosion due to the complex water body.Therefore,it is necessary to take certain protective measures to improve the surface properties of the 0Cr13Ni5Mo material and thereby delay its failure.[Methods]To enhance the service life of the flow passage components,iron-based alloy coatings with different Nb content(0％,5％,7％,and 9％)were prepared on the surface of the 0Cr13Ni5Mo substrate by laser cladding technology.X ray diffraction(XRD),scanning electron microscopy(SEM),a Vickers hardness tester,and an electrochemical workstation were used to investigate the effects of Nb addition on the microstructure,phase composition,microhardness,and electrochemical properties of the iron-based alloy coatings.[Results]The results show that the microstructure consists of grey matrix,massive and petal-like VC reinforced phases,and reticulated Cr carbides.With the increase in Nb content,the size of massive and granular Nb carbides in the matrix increases gradually,and the carbide morphology changes from massive and granular to petal-like and butterfly-like,and the reticulated Cr carbides decrease gradually.The phase composition analysis shows that the four coating samples prepared by laser cladding are composed of martensitic phase with BCC structure,austenitic phase with FCC structure,carbide reinforced phase VC,and Cr23C6 phase.With the increase in Nb content,the peaks of NbC phase appear in the XRD curves of S2,S3,and S4 samples,indicating that the carbide reinforced phase NbC is generated by the in-situ reaction of Nb during the laser cladding process,and the austenitic phase in the matrix increases gradually.The microhardness of all samples increases with the addition of Nb,with the S3 sample exhibiting the highest microhardness of 645 HV.In electrochemical tests,the self-corrosion potential of the samples gradually increases with the increase in Nb content,and the self-corrosion current gradually decreases.Samples S3 and S4 show typical anodic polarization characteristics,including the active dissolution zone,the passivation zone,and the over-passivation zone which is formed after the rupture of the passivation film.Sample S4 has a large amount of carbides,which causes micro-electro-coupling corrosion,leading to a decrease in corrosion resistance.Sample S3 has the best electrochemical performance with a self-corrosion potential of-179.3 mV,and the self-corrosion current density is only 10.3％of that of sample S1 and reaches 9.258 × 10-8 A/cm2.Its improved corrosion resistance is due to the Cr reduction in the MC-type carbides,which results in the dissolution of more Cr into the matrix phase and thereby an increase in the Cr content in the matrix phase.[Conclusion]In this study,a Nb-containing iron-based alloy coating of 0Cr13Ni5Mo material for hydraulic flow passage components was designed and prepared to promote the development of laser cladding technology for surface-strengthened coatings of flow passage components to a certain extent.关键词
激光熔覆/过流部件/马氏体/碳化物/铁基合金涂层/原位自生/显微硬度/耐腐蚀性Key words
laser cladding/overflowing part/martensite/carbide/Fe-based alloy coating/in-situ self-generation/microhardness/corrosion resistance分类
矿业与冶金引用本文复制引用
梁旭东,张松,王莉,吴臣亮,霍凤萍..合金元素Nb对激光熔覆铁基合金组织及性能的影响[J].沈阳工业大学学报,2025,47(3):332-338,7.基金项目
国家重点研发计划项目(2023YFB4606605) （2023YFB4606605）
辽宁省教育厅高等学校科研项目(LJKQZ2021050) （LJKQZ2021050）
沈阳市科技局计划项目(22-101-0-16,19-109-1-03). （22-101-0-16,19-109-1-03）
