TC11合金人造摩擦层的演变、作用及磨损机理研究

发布时间：2018-03-17 15:41

本文选题：TC11合金　切入点：纳米添加剂　出处：《江苏大学》2017年博士论文　论文类型：学位论文

【摘要】：钛合金差的摩擦学性能限制了其在涉及到摩擦、磨损工况下的应用,控制摩擦氧化物层的形成是改善钛合金摩擦磨损性能的一种新的途径。然而,目前对摩擦层的演变过程、作用及磨损机理等的研究尚不够深入。本文通过在滑动界面上添加不同类型纳米材料,人为制造出了一种双层减摩抗磨摩擦层。研究了 TC11合金在不同载荷、纳米材料添加量、滑动转数条件下的摩擦磨损行为,测试和分析了摩擦层的形态、结构及成分,探讨了磨损转变与磨损机理,探索了人造摩擦层的形成、破坏机理及二者之间的关系,阐述了人造摩擦层的作用机理和稳定性,并通过双滑动磨损实验对人造摩擦层的可持续性作用进行了验证。此项研究为钛合金的摩擦学设计和性能的改善、工程应用以及磨损理论的研究提供了基础数据和科学依据,具有重要的理论意义和工程应用价值。结果表明:TC11合金的摩擦磨损行为与添加剂类型及滑动、添加条件密切相关。无论何种载荷、添加量或转数,MLG均不能改善TC11合金的摩擦磨损性能。Fe_2O_3纳米颗粒可促使低载下的耐磨性得以提高,但减摩性并未同时得到改善。然而,Fe_2O_3和MLG的机械混合或复合材料添加剂可以同时提高TC11合金的耐磨性与减摩性。对于单独的MLG或Fe_2O_3纳米添加剂,除添加Fe_2O_3、低载条件外,均发生严重磨损,主要磨损机理为粘着磨损和磨粒磨损。而Fe_2O_3和MLG的机械混合物和复合材料添加剂加速了严重-轻微磨损转变,促使发生转变的临界载荷和临界转数增大,且临界添加量减小。随添加剂中MLG含量增加,TC11合金总体上经历了严重-轻微-严重磨损双重转变。MLG和Fe_2O_3分别依靠吸附压实和摩擦烧结形成单层人造摩擦层,MLG低的剪切力与Fe_2O_3高的硬度使得含MLG和含Fe_2O_3的单层人造摩擦层分别具有良好的润滑作用和承载能力,但单层摩擦层由于各自承载或润滑能力的欠缺导致了差的稳定性和可持续性。机械混合或复合材料中的Fe_2O_3和MLG依次经历烧结和吸附形成双层人造摩擦层,且添加机械混合材料时的双层摩擦层分层更明显。双层摩擦层综合了 MLG和Fe_2O_3各自的优势性能,表现出润滑和承载的协同保护作用,稳定性和可持续性均显著提高。研究发现,添加富Fe_2O_3复合材料时的双层人造摩擦层因Fe_2O_3含量高且分散而承载能力强,具有更好的稳定性;添加富MLG机械混合材料时的双层人造摩擦层由于MLG含量高且层数多而润滑性能优异,故可持续性更佳。双滑动磨损实验验证了添加机械混合材料时的双层人造摩擦层具有更强的可持续性。初步弄清了人造摩擦层的形成和破坏机理,基于构建的人造摩擦层形成与破坏间的关系,摩擦层演变经历生长期、稳定期和衰退期三个阶段,分别对应于VF/VD1、VF/VD≈1和VF/VD1。在不消耗基体材料且常规条件下,设计并制备出一种高稳定性、高可持续性的双层人造摩擦层,可以同时改善钛合金的摩擦磨损性能,所对应的最佳纳米添加剂类型及比例分别为MLG/Fe_2O_3(1:4)和MLG+Fe_2O_3(2:1 )。
[Abstract]:The tribological properties of titanium alloy to limit its difference of friction in the condition of the application to wear, friction of the oxide layer formation control is a new way to improve the friction and wear properties of titanium alloy. However, the current of the friction layer evolution process, the study effect and abrasion mechanism is still not deep enough. Through adding different types of nano materials in sliding interface, artificially created a double anti-wear friction layer. TC11 alloy were studied under different loads, the addition of nano materials, the friction and wear behavior of the sliding speed conditions, test and analysis of friction layer morphology, composition and structure, discusses the transformation of wear and wear the mechanism on the formation of artificial friction layer, the relationship between the failure mechanism and the two, elaborated the mechanism and stability of artificial friction layer, and the double sliding wear experiments on artificial friction layer. Persistent effect was verified. The tribological design and performance of the study for the improvement of titanium alloy, provides basic data and scientific foundation for engineering application and Research on wear theory, it has important theoretical significance and engineering application value. The results show that the friction and wear behavior of TC11 alloy with additive type and sliding, add close related. No matter what the amount of load, or rpm, MLG can not improve the friction and wear properties of.Fe_2O_3 TC11 alloy nanoparticles can promote the wear resistance under low load can be improved, but also did not improve antifriction. However, mechanical mixing or composite additives Fe_2O_3 and MLG can improve the wear resistance and antifriction TC11 alloy for MLG or Fe_2O_3 nano additive alone, in addition to Fe_2O_3, the low load conditions, are serious wear, the main wear mechanism is adhesive wear and Abrasive wear. The mechanical mixture of Fe_2O_3 and MLG and the composite additive has accelerated the serious - mild wear change, prompted the change of the critical load and speed increases, and the critical amount decreases. With the content of MLG additive increased, TC11 alloy has experienced a severe and mild severe wear double shift and.MLG Fe_2O_3 are based on the adsorption of compaction and sintering forming a layer of artificial friction friction layer, shear force and Fe_2O_3 low MLG high hardness makes single artificial friction layer containing MLG and Fe_2O_3 respectively with good lubrication and bearing capacity, but the single friction layer due to the lack of their bearing or lubricating ability leads to poor stability and sustainable. Mechanical mixed or composite materials Fe_2O_3 and MLG had undergone sintering and adsorption to form a double-layer artificial friction layer, and the double friction mechanical mixing when adding materials Double layer is more obvious. The comprehensive advantages of friction layer properties of MLG and Fe_2O_3 respectively, and the bearing lubrication showed a synergistic protective effect, stability and sustainability are significantly improved. The study found that adding two-layer synthetic friction layer rich in Fe_2O_3 composite materials because of the high content of Fe_2O_3 and dispersed and the bearing capacity is strong, has better stability; add the double artificial friction layer MLG rich materials with mechanical mixing due to the high MLG content and more layers and excellent lubrication performance, so the sustainability is better. Double sliding wear experiments verify the sustainability of the two-layer synthetic material mechanical friction layer added when mixed with stronger. We got the formation and failure mechanism of artificial friction layer the construction of artificial, friction layer formation and destruction on the basis of the friction layer undergoes growth period, stable period and recession three stages, respectively, corresponding to VF/ VD1, VF/V D = 1 and VF/VD1. in the matrix material consumption and conventional conditions, design and fabrication of a high stability, double layer artificial friction high sustainability, friction and wear properties of titanium alloy can be improved at the same time, the best proportion of nano additive types and corresponding to the MLG/ Fe_2O_3 (1:4) and MLG+Fe_2O_3 (2:1).

【学位授予单位】：江苏大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：TG146.23

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