摘要
采用光学显微镜、扫描电镜、能谱仪、硬度仪、电化学工作站和摩擦磨损试验等研究了激光增材镍基高温合金层的宏观形貌、显微组织、元素、硬度分布、电化学腐蚀性能和磨损性能。结果表明:由于基体中的石墨可以降低其附近熔点等综合因素,增材层与基体交界区域为锯齿状;在增材层出现贯穿增材层多层区域的柱状晶组织;由于激光的快速加热和冷却、基体中不同区域石墨溶解量不同等综合影响,基体靠近热影响区域可以观察到马氏体、莱氏体和残留奥氏体组织;由于基体中熔化的石墨进入增材层等综合影响,从增材层表层到增材层与基体交界区域的硬度逐渐增加;基体和激光增材区域的自腐蚀电位分别是-640 mV和-534 mV,腐蚀电流密度15.92μA·cm-2和15.03μA·cm-2,说明增材区域的抗腐蚀性能提高;由于激光增材层硬度提高等综合因素,基体的磨损率约是增材层的4.7倍。
Macroscopic morphology, microstructure, elements, hardness distribution, electrochemical corrosion properties and wear properties of Ni-based superalloy layer prepared by laser additive were investigated by means of optical microscope, scanning electron microscopy, energy spectrometer, hardness tester, electrochemical workstation and friction and wear test. The results show that the interface between the additive layer and the substrate is serrated because of the reduced melting point in the vicinity of graphite and other comprehensive factors. There is a columnar crystal structure in the additive layer that penetrates the multi-layer area of the additive layer. Due to the rapid heating and cooling of the laser and the unequal solubility of graphite in different regions of the matrix, martensite, ledeburite, and retained austenite can be observed near the heat affected zone of the substrate. Due to the combined effects of the molten graphite in the matrix entering the additive layer, from the surface of the additive layer to the interface between the additive layer and the substrate, the hardness gradually increases. The self-corrosion potential of the substrate and the laser additive layer is-640 mV and-534 mV, respectively, and the corrosion current density is 15.92 μA·cm-2 and 15.03 μA·cm-2, respectively, which indicates that the corrosion resistance of the additive layer is improved. Due to the comprehensive factors such as the increased hardness of the laser additive layer, the wear rate of the substrate is about 4.7 times that of the additive layer.
作者
庞铭
郎甜甜
PANG Ming;LANG Tian-tian(Airport College,Civil Aviation University of China,Tianjin 300300,China)
出处
《材料热处理学报》
EI
CAS
CSCD
北大核心
2020年第11期135-142,共8页
Transactions of Materials and Heat Treatment
基金
中央高校基本科研业务费项目中国民航大学专项资助(3122018D020)
中国民航大学蓝天青年科研资金资助项目(2018.3-2022.3)。
关键词
激光增材
球墨铸铁
镍基高温合金层
热影响区
laser additive
nodular cast iron
Ni-based superalloy layer
heat affected zone
