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在800℃以下,利用等电位空心阴极辉光放电特性,以针状钨钼合金棒和高纯石墨棒为源极,在Ti6Al4V合金表面进行W-Mo-C多元共渗。由于处理温度明显低于钛合金相变温度,不发生相变,避免了高温对钛合金基体的影响。利用扫描电子显微镜(SEM)观察了改性层的表面形貌和截面形貌;用XRD分析了改性层的相结构;用显微硬度计测量了显微硬度;利用球-盘摩擦磨损实验仪测试了改性层在室温干滑动摩擦条件下的耐磨性。结果表明:在温度750℃,工作气压35~50 Pa,共渗时间4 h工艺条件下,Ti6Al4V合金表面形成25μm厚的合金改性层。改性层显微硬度值达到840 HV,较基体的450 HV显著提高。改性层主要由MoTi、TixW1-x、W2C、α-Ti相组成。改性层在大幅提高钛合金表面耐磨性能的同时,也表现出良好的减摩性能,磨损量是基体材料的1/20,摩擦系数从0.50左右降为0.35。
Under 800 ℃, W-Mo-C multiple infiltration was performed on the surface of Ti6Al4V alloy by using isopotential hollow cathode glow discharge characteristics with acicular tungsten-molybdenum alloy rods and high-purity graphite rods as the source. As the treatment temperature is significantly lower than the phase transition temperature of the titanium alloy, no phase change occurs, and the effect of high temperature on the titanium alloy matrix is avoided. The surface morphology and cross-sectional morphology of the modified layer were observed by scanning electron microscopy (SEM). The phase structure of the modified layer was analyzed by XRD. The microhardness was measured by microhardness tester. The ball-plate friction and wear test The tester was tested for wear resistance of the modified layer under dry sliding friction at room temperature. The results show that a 25μm thick alloy modification layer is formed on the surface of Ti6Al4V alloy at a temperature of 750 ℃, a working pressure of 35-50 Pa and a permeation time of 4 h. The microhardness of the modified layer reached 840 HV, which was significantly higher than that of the substrate. The modified layer mainly consists of MoTi, TixW1-x, W2C and α-Ti phases. The modified layer can not only improve the wear resistance of titanium alloy but also exhibit good anti-friction performance. The wear amount is 1/20 of the base material, and the friction coefficient decreases from 0.50 to 0.35.