激光熔覆FeCrNiMo-WC复合涂层的组织与耐磨性能

Microstructure and wear resistance of laser cladding FeNiCrMo-WC composite coating

采用激光熔覆技术在Q235钢表面制备了WC陶瓷颗粒增强FeCrNiMo-WC多主元合金复合涂层。通过相组成分析、显微结构表征、力学性能测试和摩擦磨损实验等研究了WC含量对涂层组织和耐磨性能的影响。结果表明:涂层主要物相除了FCC+WC以外,还存在网状的共晶组织,由FCC与M6C碳化物相呈层片状交替分布,片层间距约100 nm;随着WC含量的增加,共晶组织体积分数增加,涂层逐渐形成共晶组织+WC陶瓷颗粒的微观组织结构;WC陶瓷颗粒的加入显著提高了涂层的硬度和耐磨性,当WC含量为40 mass%时,涂层硬度为55.9 HRC,此时涂层耐磨性能最好,最小体积磨损率为2.17×10^(-5)mm^(3)/(N·m)。涂层中大颗粒WC以及软硬交替的FCC+M_(6)C共晶体,协同提高了涂层的硬度和强韧性。同时M6C相具有减磨作用,使得涂层摩擦系数逐渐降低,磨损失效形式由粘着磨损向磨粒磨损过渡。

WC ceramic particle reinforced FeCrNiMo-WC composite coatings were prepared on Q235 steel surface by laser cladding technology.The effect of WC content on microstructure and wear resistance of the coatings was studied by means of phase composition analysis,microstructure characterization,mechanical properties testing and friction and wear experiments.The results show that besides FCC+WC,the main phase of the coatings has a network eutectic structure,which is composed of FCC and M6C carbide phases with alternating lamellar distribution,and the lamellar spacing is about 100 nm.With the increase of WC content,the volume fraction of eutectic structure increases,and the microstructure of eutectic structure+WC ceramic particles is gradually formed in the coatings.The addition of WC ceramic particles significantly improves the hardness and wear resistance of the coatings.When the WC content is 40 mass%,the hardness of the coating is 55.9 HRC,and the wear resistance is the best,with the minimum volume wear rate of 2.17×10^(-5)mm^(3)/(N·m).The hardness,strength and toughness of the coatings are improved synergistically by large WC particles and FCC+M_(6)C eutectic with alternating hard lamella and soft lamella.At the same time,the M6C phase has the function of reducing wear,which leading to the friction coefficient of the coatings gradually decrease,and the wear failure mode changes from adhesive wear to abrasive wear.