(1. 江苏大学 先进制造与现代装备技术工程研究院,镇江 212013;
2. 江苏大学 机械工程学院,镇江 212013;
3. 江苏大学 材料科学与工程学院,镇江 212013;
4. 中北大学 材料科学与工程学院,太原030051)
摘 要: 利用激光熔覆(Laser cladding, LC)技术在镍基高温合金表层制备NiCoCrAlYSi涂层,随后利用强流脉冲电子束(High current pulsed electron beam, HCPEB)技术对熔覆层表面进行辐照处理。利用X射线衍射仪(X-ray diffraction, XRD)、扫描电子显微镜(Scanning electron microscopy, SEM)等仪器观察HCPEB辐照前后激光熔覆层微观结构演变,并对比分析熔覆层表面显微硬度。结果表明:激光熔覆层主要由γ/γ′相构成,表面存在较多孔隙并具有典型的枝晶偏析现象;HCPEB辐照处理后熔覆缺陷消失,表面发生重熔并形成致密的重熔层,且重熔层厚度随辐照次数的增加而逐渐增加。此外,辐照表面诱发产生交滑移及纳米晶结构。表面显微硬度结果显示,HCPEB辐照处理后熔覆层表面硬度显著高于原始样品硬度。
关键字: 强流脉冲电子束;激光熔覆;NiCoCrAlYSi涂层;微观结构;显微硬度
(1. Engineering Institute of Advanced Manufacturing and Modern Equipment Technology, Jiangsu University, Zhenjiang 212013, China;
2. School of Mechanical Engineering, Jiangsu University, Zhenjiang 212013, China;
3. School of Materials Science and Engineering, Jiangsu University, Zhenjiang 212013, China;
4. School of Materials Science and Engineering, North University of China, Taiyuan 030051, China)
Abstract:The NiCoCrAlYSi coating was prepared on the surface of nickel-based superalloy by laser cladding(LC) technique, and then was irradiated by high current pulsed electron beam(HCPEB). X-ray diffraction(XRD) and scanning electron microscopy(SEM) were used to compare the microstructure evolution of the laser cladding coating before and after HCPEB irradiation. The surface microhardness of the cladding coating was also analyzed. The microstructural results show that the cladding coating is mainly composed of γ/γ′ phase. Many pores and typical dendritic segregation are found on the surface. After HCPEB treatment, the cladding defects disappear. The surface is remelted, and the thickness of the remelted layer gradually increase with the increase of HCPEB pulses. Besides, the cross-slip and nanocrystalline structures are induced on the irradiated surface. The surface microhardness results show that the surface hardness of the cladding coating after HCPEB treatment is significantly higher than that of the original sample.
Key words: high current pulsed electron beam; laser cladding; NiCoCrAlYSi coating; microstructure; microhardness