目的 对激光熔覆自润滑耐磨涂层进行热处理,获得具有较好摩擦学性能的复合涂层.方法 采用激光熔覆技术在TA2合金表面熔覆40%Ti-25.2%TiC-34.8%WS2复合粉末制备自润滑耐磨复合涂层.将涂层置于500℃真空中分别保温1、2 h,采用扫描电镜(SEM)、X射线衍射仪(XRD)、能谱仪(EDS)、显微硬度计、摩擦磨损试验机以及原子力显微镜(AFM)系统地分析了热处理前后涂层的物相、组织、显微硬度及摩擦学性能.结果 未经过热处理和经过热处理涂层的主要物相均为α-Ti、(Ti,W)C1-x、TiC、Ti2SC和TiS.相比未经热处理涂层的显微硬度(1049.8 HV0.5),经过热处理1 h和2 h涂层的显微硬度(1143.3 HV0.5和1162.7 HV0.5)有所上升.热处理1 h和2 h涂层的摩擦系数和磨损率分别为0.29和6.66×10?5 mm3/(N·m)以及0.29和5.65×10?5 mm3/(N·m),比未热处理涂层(0.32和18.92×10?5 mm3/(N·m))的耐磨减摩性能有所提升.经过热处理1 h和2 h涂层的磨损机理均主要表现为磨粒磨损,未经热处理涂层的磨损机理主要为塑性变形和粘着磨损.结论 相比未经热处理的涂层,经过热处理1 h和2 h的涂层显微硬度有所升高,摩擦学性能得到提升,但在两种热处理时间条件下,涂层显微硬度和摩擦学性能变化较小.
The work aims to obtain composite coatings of better tribological properties by performing heat treatment to laser cladding self-lubricating wear-resistant coatings. The composite coatings were fabricated by cladding 40% Ti-25.2% TiC-34.8%WS2 composite powder on TA2 alloy by taking advantage of laser cladding technology.The coatings were kept at 500℃ in vacuum for 1 h and 2 h, respectively, and then phases, microstructure, microhardness and tribological property of the coatings subject to heat treatment or not were analyzed with scanning electron microscope (SEM), X-ray diffractometer (XRD), energy dispersive system (EDS), microhardness tester, friction wear testing machine and atomic force microscope (AFM) sys-tematically. Main phases of the coatings subject to heat treatment or not wereα-Ti, (Ti,W)C1-x, TiC, Ti2SC and TiS. Micro-hardness of the coatings subject to 1 h and 2 h heat treatment (1143.3HV0.5 and 1162.7HV0.5) has increased compared with that of coatings not subject to heat treatment (1049.8HV0.5). Coefficient of friction and wear rate of the coatings subject to 1 h and 2 h heat treatment were 0.29 and 6.66×10?5 mm3/(N·m), 0.29 and 5.65×10?5 mm3/(N·m), respectively. Compared with the coating not subject to heat treatment (0.32 and 18.92×10?5 mm3/(N·m)), those coatings subject to heat treatment exhibited better wear resistance and antifriction property. Wear mechanism of the coatings subject to 1 h and 2 h heat treatment was mainly pre-sented as abrasive wear, while that of coatings not subject to heat treatment was mainly plastic deformation and adhesive wear. Compared with the coating not subject to heat treatment, microhardness and tribological properties of the coatings subject to 1 h and 2 h heat treatment have improved, but those of the coatings change slightly in different time of heat treatment.
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