纳米复合材料添加剂改善TC11合金摩擦磨损性能的研究

发布时间：2019-03-24 13:05

【摘要】：钛合金因其优异的综合性能而被广泛应用于诸多工业领域,但较低的塑性剪切抗力和摩擦氧化物的微弱保护作用使其耐磨性较差,阻碍了其应用。因此,改善钛合金的摩擦学性能具有重要的理论意义和工程应用价值。本文在TC11合金/GCr15钢滑动界面上添加多层石墨烯/Fe2O3复合材料,以改善钛合金的摩擦磨损性能。作为对比,同时研究了TC11合金在未添加及单独添加多层石墨烯或Fe2O3纳米颗粒下的摩擦磨损行为。采用XRD、SEM、EDS等微观分析手段对磨损表面及亚表面的形貌、结构及成分进行全面测试,重点表征了摩擦层的特征,分析了摩擦层的形成过程、作用及对摩擦磨损性能的影响,并探讨了磨损机理。结果表明,TC11合金的摩擦磨损行为与添加剂种类及载荷、添加量密切相关。单独添加多层石墨烯时,无论何种载荷或添加量,TC11合金的磨损量均比未添加时高很多,平均摩擦系数也较大。单独添加Fe2O3纳米颗粒时,低载下磨损量较低,但平均摩擦系数很高;高载下,无论何种添加量,磨损量和平均摩擦系数均较大。对于多层石墨烯/Fe2O3复合材料添加剂,在载荷20-100N或添加量0.2-0.4g下,TC11合金的磨损量和平均摩擦系数均极低;而当载荷增大至120N或添加量减小至0.1g时,磨损量和平均摩擦系数均快速升高。研究发现,当添加不同种类纳米材料时,磨损表面均形成成分各异的摩擦层,其不同的作用显著影响TC11合金的摩擦磨损性能及磨损机理。单独的多层石墨烯添加剂吸附至磨面形成摩擦层,其因含多层石墨烯而具有润滑作用,但弱的承载能力使其易于失去稳定性和保护作用,TC11合金的耐磨性未得到提高,此时的磨损机理与未添加时类似,主要为粘着磨损和磨粒磨损。单独添加Fe2O3纳米颗粒时,摩擦层的形成依靠摩擦烧结,含Fe2O3的摩擦层承载能力较强,TC11合金在低载下的耐磨性显著提高,但摩擦性能并未改善;而在高载及任一添加量下,无润滑的摩擦层在滑动中途失效,导致严重磨损的出现。当添加多层石墨烯/Fe2O3复合材料时,两组分依次经历烧结和吸附形成主要含Fe2O3和主要含多层石墨烯的摩擦层,双层摩擦层因其良好的承载、润滑能力而具有优异的协同保护作用,在较高载荷或较少添加量下可稳定存在至滑动结束,故发生轻微磨损,TC11合金的摩擦磨损性能同时得以显著改善。
[Abstract]:Titanium alloy is widely used in many industrial fields because of its excellent comprehensive properties, but its low plastic shear resistance and weak protection of friction oxides make its wear resistance poor, which hinders its application. Therefore, improving the tribological properties of titanium alloys has important theoretical significance and engineering application value. In this paper, multi-layer graphene / Fe2O3 composite was added to the sliding interface of TC11 alloy / GCr15 steel to improve the friction and wear properties of titanium alloy. As a contrast, the friction and wear behavior of TC11 alloy without or without addition of multilayer graphene or Fe2O3 nanoparticles was studied. The morphology, structure and composition of wear surface and sub-surface were tested by means of XRD,SEM,EDS and other micro-analysis methods. The characteristics of friction layer were characterized, and the formation process, effect and influence on friction and wear properties of friction layer were analyzed. The wear mechanism is also discussed. The results show that the friction and wear behavior of TC11 alloy is closely related to the type of additive, the load and the amount of additive. No matter what load or amount of graphene, the wear of TC11 alloy is much higher and the average friction coefficient is higher than that of non-adding graphene. When Fe2O3 nanoparticles were added alone, the wear amount was lower under low load, but the average friction coefficient was very high, and under high load, the wear and average friction coefficient were larger no matter what amount of nano-particles were added. For the multilayered graphene / Fe2O3 composite additive, the wear capacity and average friction coefficient of the TC11 alloy are very low under the loading of 20 渭 100N or 0.2 渭 0.4 g. However, when the load increases to 120 N or decreases to 0.1 g, the wear loss and the average friction coefficient increase rapidly. It is found that when different kinds of nano-materials are added, friction layers with different composition are formed on the wear surfaces, and the friction and wear properties and wear mechanism of TC11 alloy are significantly affected by their different effects. A single multilayer graphene additive adsorbs to the grinding surface to form a friction layer, which has lubrication effect due to the presence of multi-layer graphene, but weak bearing capacity makes it easy to lose stability and protection, and the wear resistance of TC11 alloy has not been improved. The wear mechanism is similar to that without addition, mainly adhesive wear and abrasive wear. When Fe2O3 nanoparticles were added alone, the formation of friction layer depended on friction sintering. The load carrying capacity of friction layer containing Fe2O3 was stronger, and the wear resistance of TC11 alloy under low load was improved significantly, but the friction property was not improved. Under the condition of high load and any addition, the unlubricated friction layer fails in the middle of sliding, which leads to the appearance of serious wear and tear. When multi-layer graphene / Fe2O3 composites are added, the two components undergo sintering and adsorption in turn to form the friction layer containing Fe2O3 and graphene, and the double layer friction layer has good bearing capacity. The lubrication ability of TC11 alloy has excellent synergistic protective effect, which can be stabilized until the end of sliding under higher load or less adding amount. Therefore, slight wear occurs and the friction and wear properties of the alloy can be improved significantly at the same time.
【学位授予单位】：江苏大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TG146.23

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