激光选区熔化成形nano⁃WC/CX钢微观组织及机械性能初探

Exploration on the microstructure and mechanical properties of the selective laser melted nano-WC/CX steel

摘要:

为进一步提高激光3D打印CX不锈钢材料的机械性能，首先使用静电自组装方法对CX钢粉末表面进行了纳米WC粉末的修饰，之后对经纳米WC表面修饰的CX钢粉末进行了激光选区熔化成形 (Selective laser melting，SLM)，对比了添加体积分数5%的WC前后的SLM CX钢试样的机械性能．结合金相显微镜 (OM)、扫描电子显微镜 (SEM)、能谱分析 (EDS) 及电子背散射衍射（EBSD）等材料表征手段，对SLM nano-WC/CX钢试样的微观组织结构、元素分布及相应机械性能进行了对比分析．结果表明：体积分数为5%的纳米WC的加入，对SLM nano-WC/CX钢的硬度提升有所帮助，使硬度值从352±8.2 HV_0.2提升至361±23.5 HV_0.2；尽管纳米WC的加入使SLM nano-WC/CX钢的延伸率有所降低，但其最大拉伸强度则由1091.4±6.12 MPa提升到了1109.7±15.26 MPa．总之，初步探索可以发现，通过静电自组装方法，在CX钢粉末表面添加适量的纳米WC颗粒可以有效改善SLM CX钢的最终机械性能．

Abstract:

In order to further improve the mechanical properties of the CX stainless steel， CX steel powders were surface modified via the nano-WC particles using the electrostatic self-assembly method first. Then， the nano-WC reinforced CX steel samples were fabricated via selective laser melting （SLM） technology. The microstructure characteristics， elements distribution and mechanical properties were compared between the SLM nano-WC/CX steel samples and SLM CX steel samples via a series of advanced material characterization methods including optical microscope （OM）， scanning electron microscope （SEM）， energy-dispersive X-ray spectroscopy （EDS）， electron backscatter diffraction （EBSD） and etc. The results showed that the addition of 5vol.% nano-WC promotes the hardness of the SLM nano-WC/CX steel to increase from 352±8.2 HV_0.2 to 361±23.5 HV_0.2. Although its elongation has been reduced， the ultimate tensile strength （UTS） has been increased from 1091.4±6.12 MPa to 1109.7±15.26 MPa. In short， after the preliminary explorations， it can be found that the nano-WC modified CX steel powders fabricated through the electrostatic self-assembly means can effectively enhance the mechanical properties of the SLM CX steel samples.