| 摘要: |
| 等离子修复完成后形成的表面/界面结构，对机械零件服役性能和安全可靠性至关重要，为了研究修复层表界面结构在热、力作用下的失效行为，采用等离子熔覆技术在FV520B基体上制备了钴基熔覆层，并对熔覆层表面和界面结构进行了热疲劳、常温拉伸及高温拉伸等测试，并通过扫描电镜、金相显微镜对其组织进行观察。结果表明：钴基熔覆层在600 ℃具有优异的抗热疲劳性能，随着温度升高熔覆层表界面结构疲劳性能降低，疲劳裂纹在涂层与基体间界面处萌生；单轴拉力作用下表界面结构中的涂层发生断裂，进一步研究发现涂层中的多层搭接位置晶粒粗大发生断裂；300~700 ℃高温拉伸实验中，钴基熔覆层体系在各种温度下均失效于涂层位置，随着合金元素的加入熔覆层强度提升，断裂失效的位置由原来的涂层处转移到基体。 |
| 关键词: Co基等离子熔覆层 表面/界面 热力耦合 失效行为 |
| DOI：10.11933/j.issn.1007-9289.20181120001 |
| 分类号:TG174.44 |
| 基金项目:国家自然科学基金（51975137） |
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| Failure Behavior of Cobalt-based Plasma Cladding Layer in Thermal and Mechanical Conditions |
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LI Yang1, TAN Na1, CUI Xiufang2, JIN Guo2
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1.National-Local Joint Engineering Laboratory of Intelligent Manufacturing Oriented Automobile Die & Mould, Tianjin University of Technology and Education, Tianjin 300222, China;2.College of Material Science and Chemical Engineering, Harbin Engineering University, Harbin 150001, China
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| Abstract: |
| Surface/interface structure is crucial to the service performance and safety reliability of mechanical parts. To study the failure behavior of surface/interface structure under the action of thermal and mechanical, cobalt-based cladding layer was prepared on FV520B substrate by plasma cladding technology, the surface/interface structure of the cladding layer was detected through thermal fatigue test, tensile test at normal/high temperature, and the microstructure was observed by a scanning electron microscope and a metallographic microscope. Results show that cobalt-based cladding layer has excellent thermal fatigue resistance at 600 ℃, and the fatigue resistance of the surface/interface structure of cladding layer decreases with the increasing of temperature, and the fatigue crack originates in the interface between the coating and the substrate. The coating breaks in the uniaxial tensile experiment, and further studies show that the coarse dendrite are broken at the multilayer lap position. In high-temperature tensile experiment between 300 and 700 ℃, the surface/interface structure of cobalt-based cladding layer failes inner the coating at various temperatures, while the failure position transferres from the coating to the substrate as the strength of the cladding layer increased with the addition of alloy elements. |
| Key words: cobalt-based plasma cladding layer surface/interface thermal mechanical coupling failure behavior |
