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

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.

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),energydispersive X-ray spectroscopy(EDS),electron backscatter diffraction(EBSD)and etc. The results showed that the addition of 5 vol. % 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.