富Co-layers硬质合金表面渗氮处理微观结构和性能研究

发布时间：2018-05-24 09:25

  本文选题：硬质合金 + 硬质相　； 参考：《材料导报》2017年08期

【摘要】：采用两步法烧结工艺制备了表面富Co-layers硬质合金和表面富Ti基硬质相层硬质合金,对比研究了氮化处理前后硬质合金表面微观形貌、生成相和力学性能的差异。研究表明:真空条件下烧结可在试样表层生成约20μm厚的Co-layers,该层中不含立方碳化物相,微观结构分析发现试样表面呈现山丘形貌且具有金属亮银色光泽,可用于修复试样表面缺陷,如微观裂纹、孔洞等,并且改善硬质合金表面韧性和提高涂层与基体之间的界面结合强度。氮化处理可在合金表面原位生成富含细晶粒的TiN相层,层厚约1μm,微观结构分析发现该层呈金色或棕色,表面较为平整。通过性能对比分析发现渗氮虽然导致试样密度小幅降低,但是可显著改善晶粒尺寸分布不均和增加表层硬质相中的微应变,能够在提高表面硬度的同时依然保持较高韧性,同时可有效改善硬质合金的刀具耐磨性和使用寿命。
[Abstract]:The surface cemented carbides rich in Co-layers and Ti-based cemented carbides were prepared by two-step sintering process. The surface morphology, phase formation and mechanical properties of the cemented carbides before and after nitriding were compared and studied. The results show that Co-layers20 渭 m thick can be formed on the surface of the sample by sintering under vacuum condition. There is no cubic carbide phase in the layer. The microstructure analysis shows that the surface of the sample has a mound shape and a bright silver metallic gloss. It can be used to repair surface defects, such as micro-cracks, pores, etc., and to improve the surface toughness of cemented carbides and the interfacial bonding strength between coating and substrate. After nitriding, the TiN layer rich in fine grains was formed on the surface of the alloy. The thickness of the layer was about 1 渭 m. The microstructure of the layer was found to be golden or brown, and the surface was flat. It is found that nitriding can significantly improve the uneven distribution of grain size and increase the micro-strain in the hard phase of the surface layer although nitriding leads to a small decrease in the density of the sample. The nitriding can increase the hardness of the surface and maintain the high toughness at the same time. At the same time, it can effectively improve the wear resistance and service life of cemented carbide tools.
【作者单位】： 岭南师范学院机电工程研究所;广东工业大学机电工程学院;
【基金】：广东省自然科学基金(S2013010012107) 广东省扬帆计划科研创新团队项目(411282606110) 岭南师范学院科研创新团队项目;岭南师范学院新材料与先进制造协调创新中心项目
【分类号】：TG156.82
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本文编号：1928534