(北京航空航天大学 材料科学工程学院 大型整体金属构件激光直接制造教育部工程研究中心,北京 100191)
摘 要: 为了提高TA15钛合金的耐磨性,在TA15钛合金表面利用激光熔覆预置的大粒度WC颗粒与TA15混合粉末层制备WC颗粒增强耐磨复合涂层。采用金相显微镜(OM)、扫描电镜(SEM)分析涂层的显微组织,采用X射线衍射(XRD)结合能谱(EDS)对涂层进行物相鉴定,测试涂层在二体磨料磨损及室温干滑动磨损条件下的耐磨损性能并分析磨损机理。结果表明:增强相WC颗粒在涂层中较均匀分布,初生(TiW)C/TiC相和(TiW)C+(Ti, W)共晶组织组成增强相的基体,涂层在二体磨料磨损及干滑动磨损条件下表现出优异的耐磨性能,较钛合金基材耐磨性能提高几十至上百倍;WC颗粒与基体中韧性的高硬相及优异的抗粘着性能对涂层耐磨性起主导作用。
关键字: 激光熔覆;颗粒增强;钛合金;碳化钨;耐磨性
(Engineering Research Center of Ministry of Education on Laser Direct Manufacturing for Large Metallic Components,
School of Materials Science and Engineering, Beijing University of Aeronautics and Astronautics, Beijing 100191, China)
Abstract:The wear resistant composite coatings reinforced by WC particles were fabricated by laser cladding using blends of WC particles with large size and TA15 powders as the raw materials. Microstructure and worn surface morphologies of the coatings were analyzed and characterized by optical microscopy (OM), scan electron microscopy (SEM) equipped with energy dispersive spectrometer (EDS) and X-ray diffraction (XRD). Wear resistance of the coatings was evaluated under two-body abrasive and dry sliding wear test condition at room temperature. The results show that WC particles have a uniform distribution in the coatings, which consists of the primary phase (TiW)C/TiC and (TiW)C+(Ti,W) eutectic phase as the matrix. Under two-body abrasive and block-on-ring dry sliding wear conditions, compared with titanium alloy substrate, the wear-resistance of coatings has improved dozens to one hundred times. High hardness of WC particles and the tough matrix with excellent anti-adhesion properties play a key role in improving wear resistance of the coatings.
Key words: laser cladding; particles reinforcement; titanium; WC; wear resistance