CO_2激光熔覆镍基合金粉末的组织和性能

为了提高核发电成套设备的阀体性能,采用CO_2激光器在SUS316LN奥氏体不锈钢表面熔覆了镍基合金粉末.利用光学显微镜、扫描电子显微镜、电子探针分析仪、X射线衍射仪、能谱分析仪、显微硬度计和磨损试验机等对熔覆层的组织和性能进行了研究.结果表明,从熔覆层熔合线到表面的组织依次由平面晶生长区、亚共晶区,共晶区与过共晶区组成.亚共晶组织的初晶相由γ-Ni相组成,而过共晶组织的初晶相由Cr B和Cr7C3相组成.CO_2激光熔覆层具有较高的维氏硬度和耐磨性能,且其裂纹断口形貌属于解理断裂.

Microstructure and performance of Ni based alloy powder prepared with CO2 laser cladding

In order to improve the performance of valve body in the complete nuclear power generation equipment, the Ni-based alloy powder was deposited on the surface of SUS316LN austenitic stainless steel with CO₂ laser. The microstructure and performance of cladding layer were analyzed with the optical microscope(OM), scanning electronic microscope(SEM), electronic probe microanalyzer(EPMA), X ray diffractometer(XRD), energy dispersive spectrometer(EDS), micro-hardness tester and wear tester. The results show that the microstructures from the fusion line of cladding layer to the surface are composed of the planar crystal growth zone, hypoeutectic zone, eutectic zone and hypereutectic zone, respectively. The primary phase in the hypoeutectic microstructure is γ-Ni phase, and the primary phases in the hypereutectic structure consist of CrB and Cr₇C₃ phases. The CO₂ laser cladding layer has higher Vickers hardness and wear resistance, and the fracture mode of the layer belongs to the cleavage fracture.