车用不锈钢表面激光定向能量沉积WC/Co基复合强化涂层研究

Research on Laser directed energy deposition of WC/ Co-based Strengthened Coating on the Surface of Automotive Stainless Steel

  • 摘要: 为提高车用304不锈钢表面的耐磨性和使用寿命,本文采用激光定向能量沉积技术在其表面制备了WC/Co基复合强化涂层,系统研究了不同WC颗粒含量对涂层组织结构及性能的影响。通过光学显微镜观察、X射线衍射分析、硬度测试及摩擦磨损试验等手段,分析了涂层的微观组织演变、物相组成、硬度变化及耐磨性能。研究结果表明,涂层主要由fcc-Co、Co₆W₆C、Fe₆W₆C及W₂C相组成,随着WC颗粒含量的增加,涂层中硬质相含量提升,晶粒细化现象明显。涂层的宏-微观硬度随WC含量升高而显著增强,当WC颗粒含量为40%时,洛氏和维氏硬度分别达到86.4 HRA和1123.7 HV₀.₅。同时,涂层的磨损速率随WC颗粒含量增加而大幅降低,耐磨性明显改善,WC颗粒通过第二相强化、细晶强化和弥散强化机制,有效提升了涂层的综合力学性能。本研究为车用不锈钢零部件表面改性强化提供了理论依据和技术参考。

     

    Abstract: To enhance the wear resistance and service life of automotive 304 stainless steel surfaces, WC/Co-based composite reinforced coatings were fabricated via laser directed energy deposition. The effects of different WC particle contents on the microstructure and properties of the coatings were systematically investigated. Through optical microscopy observation, X-ray diffraction analysis, hardness testing, and friction and wear experiments, the evolution of the microstructure, phase composition, hardness variations, and wear resistance of the coatings were comprehensively analyzed. The results show that the coatings mainly consist of fcc-Co, Co₆W₆C, Fe₆W₆C, and W₂C phases. With the increase of WC particle content, the proportion of hard phases rises and significant grain refinement occurs. Both macro- and micro-hardness of the coatings increase markedly with higher WC content, reaching 86.4 HRA and 1123.7 HV₀.₅ when the WC content is 40%. Meanwhile, the wear rate of the coatings decreases significantly with the addition of WC particles, and the wear resistance is substantially improved. The enhancement in mechanical properties is attributed to second-phase strengthening, grain refinement strengthening, and dispersion strengthening mechanisms induced by WC particles. This study provides theoretical guidance and technical support for the surface modification and strengthening of automotive stainless steel components.

     

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