TD3合金及其表面改性后摩擦磨损行为研究

发布时间：2018-12-27 07:53

【摘要】：TD3合金是一种中等Nb含量的Ti_3Al基合金,作为比重小、耐高温结构材料,受到了航空航天工业的关注,目前对TD3合金的研究大多集中在其微观结构和力学性能方面,对其摩擦磨损性能的研究很少报道。本文研究TD3合金在不同载荷、滑动速度条件下的摩擦系数、磨痕表面形貌及磨损量的变化规律,对TD3合金摩擦磨损机理进行初步的探究。为了进一步改善TD3合金的摩擦磨损性能,采用热氧化技术、离子氮化技术在TD3合金分别表面制备两种改性层,利用光学金相显微镜(OA)、扫描电子显微镜(SEM)、能谱分析仪(EDS)、X射线衍射(XRD)及显微硬度计分别对两种改性层的形貌、成份、物相结构及硬度进行测试分析。结果表明TD3合金热氧化后的表面形成含TiO_2、Al2O3的致密均匀的氧化层,厚度达7μm,其表层硬度可达638HV;TD3合金离子氮化后的表面形成含有TiN、Ti2N的渗氮层,渗氮层由化合物层和过渡层组成,厚度可达80μm,渗层硬度可达1190HV,为基材硬度的3倍以上。使用往复式摩擦磨损试验机研究不同载荷、滑动速度条件下TD3合金热氧化后及离子氮化后摩擦系数随时间的变化,利用SEM、EDS、白光干涉3D轮廓仪等仪器对磨痕形貌、尺寸及成份进行测量分析。实验结果表明,与TD3合金相比,同实验条件下TD3合金热氧化后平均摩擦系数可降低50%,载荷100g时体积磨损量减小0.197,氧化层起到了较好的减磨效果;渗氮后的TD3在不同载荷下的摩擦系数、磨损量均减小,100g载荷下的磨损量减小50%以上。TD3合金渗氮后摩擦磨损学性能得到改善。
[Abstract]:TD3 alloy is a kind of Ti_3Al base alloy with medium Nb content. As a kind of low specific gravity and high temperature resistant structural material, TD3 alloy has been paid much attention by aerospace industry. At present, most of the researches on TD3 alloy focus on its microstructure and mechanical properties. The study of friction and wear properties is seldom reported. In this paper, the friction coefficient, surface morphology and wear quantity of TD3 alloy under different load and sliding speed are studied. The friction and wear mechanism of TD3 alloy is studied. In order to further improve the friction and wear properties of TD3 alloy, two kinds of modified layers were prepared on the surface of TD3 alloy by thermal oxidation technique and ion nitriding technique. Optical metallographic microscope (OA),) scanning electron microscope (SEM),) was used to improve the friction and wear properties of TD3 alloy. The morphology, composition, phase structure and hardness of the two modified layers were measured and analyzed by (EDS), X ray diffraction (XRD) and microhardness tester respectively. The results show that a dense and uniform oxidation layer containing TiO_2,Al2O3 is formed on the surface of TD3 alloy after thermal oxidation. The thickness is 7 渭 m, and the hardness of the surface layer can reach 638 HV; The nitriding layer containing TiN,Ti2N is formed on the surface of TD3 alloy after ion nitriding. The nitriding layer is composed of compound layer and transition layer. The thickness of nitriding layer is up to 80 渭 m, and the hardness of the nitriding layer can reach 1190HVV, which is more than three times of the hardness of substrate. A reciprocating friction and wear tester was used to study the variation of friction coefficient with time after thermal oxidation and ion nitriding of TD3 alloy under different load and sliding speed. The wear marks were observed by means of SEM,EDS, white light interference 3D profilometer. Dimensions and components are measured and analyzed. The experimental results show that compared with TD3 alloy, the average friction coefficient of TD3 alloy after thermal oxidation can be reduced by 50 and the volume wear of TD3 alloy can be reduced by 0.197 when the load is 100 g. The oxidation layer has a better effect on reducing wear. The friction coefficient and wear amount of nitrided TD3 are all decreased under different loads, and the wear amount of TD3 alloy is reduced by more than 50% under 100g load. The friction and wear properties of TD3 alloy are improved after nitriding.
【学位授予单位】：太原理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TG174.4

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