氩弧熔覆原位合成WCp增强铁基涂层组织与耐磨性

发布时间：2018-04-23 01:37

本文选题：原位合成 + WC　；参考：《湘潭大学》2015年硕士论文

【摘要】：原位自生金属基复合材料因具有高比强度,与基体有良好的润湿性和结合强度,已成为国内外研究的热点。本文选用廉价的钨铁和石墨作为原位合成WC的钨源和碳源,采用氩弧焊方法在Q235钢表面熔覆一层性能优良的耐磨涂层。同时借助光学显微镜、扫描电镜(SEM)、X射线衍射仪(XRD)、洛氏硬度计、显微硬度计以及磨粒磨损试验机等实验仪器,研究了C/W、Si、Mn、外加WC粉末以及预烧结处理对氩弧熔覆原位制备WC颗粒增强涂层组织与性能的影响。研究结果表明:(1)当C/W小于1:1时,涂层中未发现WC颗粒,涂层中的碳化物主要以Fe3W3C等为主。当C/W为1.25:1时,涂层中开始生成WC。而当C/W为1.5:1时,涂层中的WC含量增加,且分布较为均匀,此时涂层的耐磨性达到最佳。(2)合金元素Si对涂层组织和性能有显著影响。随着硅含量的增加,碳原子聚集倾向增大,致使涂层中形成多个富碳区域,提高WC的形核率。当硅含量为5%时,WC分布较均匀,对基体构成了良好的阴影保护效果。其相对耐磨性达到最高,是基体的58倍左右。而合金元素Mn对涂层的组织没有显著影响,但对涂层的性能有明显作用。随着锰含量的增加,涂层硬度增加,而涂层的耐磨性则呈先升高后下降的变化规律。(3)外加WC粉末作为非均匀形核的形核基底,大大增加了原位合成WC的形核率。当外加WC含量达到5%时,原位合成的WC均匀分布在涂层中,其耐磨达到最佳。而钨铁与石墨经过预烧结后,钨铁表面吸附有大量的石墨,从而使得存在多个富碳区域。在电弧反应过程中,涂层中生成了大量的WC颗粒且均匀分布于涂层中上部,涂层耐磨性大大提高。
[Abstract]:In-situ in-situ metal matrix composites with high specific strength, good wettability and bonding strength with the matrix have become a hot research topic at home and abroad. In this paper, cheap iron tungsten and graphite are used as tungsten and carbon sources for in-situ synthesis of WC. An excellent wear-resistant coating is cladding on Q235 steel by argon arc welding. At the same time, with the help of optical microscope, scanning electron microscope, SEMU X-ray diffractometer, Rockwell hardness tester, microhardness meter and abrasive wear tester, etc. The effects of C / W / Si Si mn, WC powder and pre-sintering on the microstructure and properties of in-situ prepared WC particle reinforced coatings by argon arc cladding were investigated. The results show that when the C / W is less than 1:1, no WC particles are found in the coating, and the carbides in the coating are mainly Fe3W3C and so on. When C / W is 1. 25: 1, WC is formed in the coating. When the C / W is 1.5: 1, the WC content in the coating increases and the distribution is more uniform, and the wear resistance of the coating reaches the best. The alloy element Si has a significant effect on the microstructure and properties of the coating. With the increase of silicon content, the tendency of carbon atom aggregation increases, resulting in the formation of many carbon-rich regions in the coating, and the nucleation rate of WC is increased. When the silicon content is 5, the WC distribution is more uniform, and it has a good shadow protection effect on the matrix. Its relative wear resistance is the highest, about 58 times of the matrix. The alloy element mn has no significant effect on the microstructure of the coating, but has obvious effect on the properties of the coating. With the increase of manganese content, the hardness of the coating increases, while the wear resistance of the coating increases first and then decreases. The addition of WC powder as the nucleation substrate of heterogeneous nucleation greatly increases the nucleation rate of in-situ synthesized WC. When the content of WC in the coating reaches 5, the WC synthesized in situ is uniformly distributed in the coating, and the wear resistance is the best. After presintering, there are a lot of graphite adsorbed on the surface of ferric tungsten and graphite, which leads to the existence of many carbon-rich regions. During the arc reaction, a large number of WC particles were formed in the coating and distributed uniformly in the middle and upper parts of the coating. The wear resistance of the coating was greatly improved.
【学位授予单位】：湘潭大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TG174.4

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