润滑条件下Mg2B2O5/6061Al基复合材料摩擦磨损性能研究

采用自制的机械-超声混合搅拌设备制备出Mg2B2O5/6061Al铝基复合材料,复合材料的体积分数为2%。研究了载荷和滑动速度对基体以及复合材料的摩擦磨损性能的影响。实验结果表明,基体和复合材料摩擦系数总体上随着载荷和滑动速度的增加而减小。基体和复合材料的磨损率随载荷和滑动速度的增加而明显的增大,且基体和复合材料均存在一个临界载荷和临界滑动速度。当载荷和滑动速度到达临界值后,磨损率均急剧增大,此时试样摩擦磨损机制由微观疲劳磨损和磨粒磨损向粘着磨损与剥离磨损转变。     

原位合成Al2O3增强铝基复合材料的摩擦磨损性能

通过采用粉末冶金和原位合成技术相结合的近净成形技术制备Al-5％Si-Al2O3复合材料,并运用M一2000摩擦磨损试验机对该复合材料的摩擦磨损性能进行研究。通过单一变量比较法分析载荷和滑动速度对Al-5％Si-Al2O3复合材料摩擦磨损性能的影响,同时对长时间连续磨损下该材料的摩擦性能进行研究。通过扫描电子显微镜对Al-5％Si-Al2O3复合材料的磨损表面进行观察,并分析其磨损机制。结果表明,随着载荷的增大,试样的磨损量和摩擦因数均增加;随着滑动速度的增大,试样表面的升温使得产生氧化层的速率增加,试样的磨损量和摩擦因数均减少。在长时间的连续磨损过程中,由于初始时发生粘着磨损,试样的摩擦因数随着滑动距离的增大而增大。然后,试样表面氧化层的形成和破坏趋于动态平衡,试样表面相对稳定,其摩擦因数也随之趋于平稳。铝基复合材料的磨损机制主要为磨粒磨损、粘着磨损和氧化磨损。     

体育器材用Ti_2AlC复合材料的磨损性能研究

通过改变加载载荷和滑动速度的方法,模拟实际工作中的使用条件,研究了体育器材用Ti_2AlC复合材料的摩擦磨损性能,对表面磨损形貌进行了观察,并分析了其作用机理。结果表明,Ti_2AlC复合材料的摩擦系数会随着滑动速度的增加或者载荷的增加而降低;随着滑动速度的增加,Ti_2AlC复合材料的磨损率呈现先降低而后升高的趋势,在滑动速度为4.8 m/s时取得磨损率的最小值;Ti_2AlC复合材料的磨损形式主要为层状剥落和氧化磨损。     

硼酸镁晶须增强镁基复合材料的摩擦性能及磨损行为

研究真空气压渗流法制备的硼酸镁晶须增强镁基复合材料(体积分数30%)及其基体合金在液体石蜡润滑条件下的滑动摩擦磨损性能.试验条件为滑动距离2 km,滑动速度0.5、1.0、2.0、3.0和5.0 m/s,载荷5、10、18、25和40 N.结果表明:在润滑条件下,引入增强相MgB2O5能提高复合材料在低载下的耐磨性能.随着载荷的增加,复合材料的磨损由轻微磨损向严霞磨损转变.临界载荷分别为:1 m/s,25N:2m/s,18N:3m/s,10N;5 m/s,5 N.复合材料磨损情况的扫描电了显微分析和观察显示,复合材料在两种摩损阶段的主导磨损机制分别为磨粒和剥层磨损.研究还发现,复合材料由轻微磨损阶段向严重磨损阶段的转变不仪与载荷有关,还与滑动速度有关.     

载荷对钢基自生复合材料高速磨损性能的影响

采用铸造的方法制备了钢基自生复合材料,并通过MMS-1G高速销盘摩擦磨损试验机、扫描电镜和能谱仪,研究了钢基自生复合材料的微观组织和载荷对该复合材料高速磨损性能的影响.结果表明,制备的复合材料中自生碳化物颗粒细小、圆整、分布均匀,自生碳化物体积分数可达到31%左右.在40m/s的滑动速度下,钢基自生复合材料的磨损率随载荷的提高而增大,当载荷从50N增加至150N时,该复合材料的磨损率也由0.99×10-6g/m增加到4.2×10-6g/m,复合材料的摩擦因数则随载荷增加而降低.对自生复合材料的磨损机理进行了探讨.     

增强颗粒对镁基复合材料磨损性能的影响(英文)

研究增强颗粒Mg2Si对镁基复合材料摩擦磨损性能的影响,讨论Si加入量、载荷和滑动速度对Mg2Si/AM60镁基复合材料磨损性能的影响。结果表明,向镁合金中加入合金元素Si,可原位生成增强颗粒Mg2Si,增强颗粒Mg2Si可明显提高AM60镁合金的磨损性能。随着载荷和滑动速度的增加,AM60镁合金和Mg2Si/AM60镁基复合材料的磨损量都增大。AM60镁合金的磨损机制为粘着磨损。随着载荷的增大,Mg2Si/AM60镁基复合材料的磨损由磨粒磨损向粘着磨损转变。     

6061铝合金/岩粉复合材料的干滑动磨损行为(英文)

研究岩粉尺寸(10~30μm)和质量分数(5%~15%)对搅拌铸造法制备6061铝合金/岩粉复合材料密度、硬度和干滑动磨损行为的影响。在不同载荷、不同滑动速率和滑动距离条件下在销盘摩擦试验机上对复合材料进行干滑动摩擦磨损试验。采用Taguchi法进行正交试验(L27)设计,并对实验结果进行方差分析。结果表明,载荷和增强相(岩粉)尺寸是影响复合材料样品比摩损率的主要因素,其次为增强相的质量分数、滑动速率、滑动距离,且其影响程度分别为47.61%、28.57%、19.04%、9.52%和4.76%。对所得回归方程的预测精度进行实验论证,结果显示,此回归方程能用于复合材料的磨损率的预测且预测误差很小。复合材料磨损表面的SEM结果表明,以岩粉作为增强相能改善铝合金材料的耐磨性能。     

反应热压制备不同SiO_2/C/Al摩尔比原位自生铝基复合材料的耐磨性能（英文）

反应热压法制备不同SiO_2/C/Al摩尔比的原位自生铝基复合材料。采用销-盘式摩擦试验机对这些复合材料进行干滑动摩擦试验。利用扫描电镜和能谱分析研究复合材料表面成分和形貌。结果表明,当SiO_2/C/Al摩尔比为3:6:9时,原位生成更多Al_2O_3、SiC和Si颗粒,在Al-SiO_2-C体系中Al_4C_3相被彻底抑制,因此复合材料的耐磨性能大幅度提高。当滑动速度从0.4 m/s增加到1.6 m/s时,磨损量逐渐减小。当摩擦载荷增加时,磨损量也增加。观察到的犁沟、磨损坑和细微纹沟说明磨料磨损是主要的磨损机制。然而,当采用更高的滑动速度时,只有氧化磨损机制控制复合材料的磨损行为。     

不同载荷下再生复合辊环耐磨性能研究

通过对回收的废旧复合辊环材料进行重熔和离心铸造,制备了由耐磨WCp颗粒增强的复合层与Fe-C合金基体组成的再生复合材料辊环,并采用MMS-1G高速销-盘摩擦磨损试验机、扫描电镜(SEM),研究了在100、150和200 N载荷下滑动速度对再生复合辊环的摩擦性能的影响.结果表明,在100、150和200 N载荷条件下,随滑动速度的增加,再生复合辊环的磨损率均出现幅度很小的波动现象,而摩擦因数先降低后缓慢增加.在相同滑动速度条件下,磨损率明显随载荷的增加而增大,而摩擦因数随载荷的增加而降低.再生复合辊环在低速条件下的磨损机理主要为犁沟磨损和塑性变形,而当滑动速度较高时,表现为粘着磨损、氧化磨损和磨粒磨损.     

搅拌铸造AA6061-T6/AlNp复合材料的干滑动磨损行为

以AA6061为基体、AlN颗粒为增强体,采用搅拌铸造工艺得到AA6061-T6/AlNp复合材料,研究了AA6061-T6/AlNp复合材料的干滑动磨损行为。开发回归模型来预测复合材料的磨损率。采用四因素、五水平的正交实验进行优化。实验因素包括滑动速度、滑动距离、荷载、增强体AlN颗粒的质量分数。采用SYSTAT 12软件和统计工具,如方差分析（方差分析）和t实验,验证回归模型。结果表明,开发的回归模型可以有效预测复合材料的磨损率,置信度达95%。采用回归模型,并依据磨损表面形貌分析,预测实验因素对AA6061-T6/AlNp复合材料磨损率的影响。回归模型预测结果表明,复合材料的磨损率随着增强体AlN质量分数的增加而降低,随着滑动速度、滑动距离、荷载的增加而增加。     

Dry Sliding Tribological Studies of AA6061-B<Subscript>4</Subscript>C-Gr Hybrid Composites

The dry sliding behavior of stir-cast AA6061-10 wt.% B₄C composites containing 2.5, 5 and 7.5 wt.% graphite particles was studied as a function of applied load, sliding speed and sliding distance on a pin-on-disk tribotester. The wear rate and friction coefficient increased with increase in applied load and sliding distance. The increase in graphite addition reduced the increase in wear rate and friction coefficient in the sliding speed range 2-2.5 m/s. Scanning electron microscopy of the worn pin revealed a graphite tribolayer, and transmission electron microscopy revealed overlapping deformation bands under 30 N applied load. Upon increasing the applied load to 40 N, welded region with fine crystalline structure was formed due to dynamic recrystallization of AA6061 alloy matrix.     

[1]ZrB2P/6061Al复合材料的大功率高速激光焊接成形和组织演变

本文通过原位合成法制备5 wt.% ZrB2p/6061Al复合材料,并对其进行激光焊接组织和力学性能研究。XRD和EDS分析表明,通过Al-K2ZrF6-KBF4原位反应体系成功制备5 wt.% ZrB2p/6061Al复合材料。通过OM和SEM分析,与基体6061Al合金相比,ZrB2p/6061Al复合材料中的纳米ZrB2?颗粒产生的异质形核和钉扎效应对基体晶粒具有一定的晶粒细化作用,但纳米级颗粒团簇体的存在使其细化效果受到局限。进行激光焊接试验,在保证完全焊透的情况下,采用3.6 kW、2.4 m/min的大功率高速焊接可获得成形良好的焊缝。激光快速熔凝过程使基体晶粒进一步高度细化,大量ZrB2团簇体基本消失,ZrB2颗粒基本均匀分散,通过电子显微镜研究ZrB2颗粒的迁移行为,发现激光熔池的熔体搅动和快速凝固过程实现了ZrB2颗粒的两次分布。焊缝组织的优化提高了焊接接头的维氏硬度和抗拉强度,分别最高达到57.3 HV和125.17 MPa,并探讨了焊缝的强化机制。     

原位颗粒对铝基复合材料组织及磨损性能的影响

采用原位反应近液相线铸造法制备铝基复合材料,分析其铸态组织,测试不同条件下铝基合金的滑动磨损特性.结果表明,原位TiC和Al2O3颗粒对铝合金的铸态组织均具有细化作用.在同等条件下(转速或压力相同)复合材料的磨损性能优于基体材料,这说明原位颗粒的加入显著提高了材料的磨损性能,复合材料比基体的磨损性能提高了1.5～4倍;且复合材料的磨损量随着载荷的增加而增大,随着转速的升高而减小,它在高速低载条件下表现出较好的摩擦磨损特性.     

Dry sliding wear characterization of squeeze cast LM13/FeCu composite using response surface methodology

Dry sliding wear is one of the predominant factors to be considered while selecting material for automotive and aerospace applications. Researchers have been exploring novel aluminium matrix composites(AMC), which offer minimum wear rate for various tribological applications. In this present work, an attempt has been made to reinforce LM13 aluminium alloy with copper coated steel fibers(10 wt.%) using squeeze casting process and to perform dry sliding wear test using pin-on-disc tribometer. Microstructure of cast samples was examined using image analysis system to investigate the dispersion of reinforcement in matrix. Dry sliding wear test was performed by considering factors such as load(10–50 N), sliding velocity(1–5 m·s(-1)) and sliding distance(500–2,500 m). Wear test was performed according to the experimental design at room temperature. Three factors and five levels central composite design were used to design the experiments using response surface methodology. Based on the results of the experiments, a regression model was developed to predict the wear rate of composites and checked for its adequacy using significance tests, analyses of variance and confirmation tests. Worn surface of samples was investigated using field emission scanning electron microscope and reported with its mechanisms. Microstructure of cast samples revealed uniform dispersion of reinforcement throughout the matrix. Response surface plots revealed that wear rate of composites increases with increasing load up to 50 N with the velocity 1–5 m·s(-1) and a sliding distance up to 2,500 m. However wear rate decreasesd with increasing velocity at lower loads(up to 20 N) and increased after reaching transition velocity of 2 m·s(-1). Dry sliding wear process parameters were optimised for obtaining minimum wear rate and they were found to be a load of 18.46 N, velocity of 4.11 m·s(-1), sliding distance of 923 m. Worn surface of samples revealed a mild wear at lower loads(up to 30 N), and severe wear was observed at high loads(40–50 N) due to higher level of deformation on the surface.     

Effect of reinforcement,compact pressure and hard ceramic coating on aluminium rock dust composite performance

Aluminium 6061T6 is reinforced with naturally available rock dust particles to fabricate low cost aluminium rock dust composite through powder metallurgy technique. Reinforcement ratio was varied from 0% to 50% whereas size of the particles was kept constant as 20 μm. Mixed powders were compacted at three different pressures from 100 to 200 MPa. Al₂O₃ ceramic coating was given over the novel composite material by Type III Sulphuric acid hard coating method. Developed composites were tested for microstructure, micro-hardness and wear resistance. SEM micrograph confirms uniform distribution of reinforcement in matrix and a fine ceramic hard coating is observed through optical microscopic images. Micro-hardness increases as reinforcement level increases up to 10%. Wear properties were analysed using pin on disc setup without lubricant and by maintaining three parameters viz load, sliding velocity and sliding distance being unchanged. It was found that composite with 10% rock dust gives better wear resistance than any other compositions. Also incrementing figure is notified for hardness and subsequently wear resisting property too when compacting pressure gets increased. Coated sample exhibits better performance than uncoated composite samples at all compositions and at different levels of compacting pressure.     

溶渗法制备Al3Ti/Al复合材料的研究

以钛丝网为反应源,以金属Al为基体,通过熔渗+原位反应法制备出一种Al3Ti金属间化合物颗粒增强铝基表面复合涂层。根据差热分析结果确定了反应温度为890℃;通过XRD、SEM以及显微硬度和磨损测试对所得到的复合涂层进行了表征。结果表明:当保温时间为20 min时,钛丝在铝基体中的反应较完全,原位合成为块状和条状的Al3Ti颗粒;颗粒的显微硬度大约为基体的4.5倍;在载荷为10 N的干滑动磨损条件下,相对于没有增强的Al基体而言,保温20 min所制备的复合涂层表现出较好的耐磨性,其磨损机制为粘着磨损和磨粒磨损共存。     

High temperature tribological behaviors of aluminum matrix composites reinforced with solid lubricant particles

The AA6061−10wt.%B₄C mono composite, AA6061−10wt.%B₄C−Gr (Gr: graphite) hybrid composites containing 2.5, 5, and 7.5 wt.% Gr particles, and AA6061−10wt.%B₄C−MoS₂ hybrid composites containing 2.5, 5, and 7.5 wt.% MoS₂ particles were fabricated through stir casting. The dry sliding tribological behaviors of the mono composite and hybrid composites were studied as a function of temperature on high temperature pin-on-disc tribotester against EN 31 counterface. The wear rate and friction coefficient of the Gr-reinforced and MoS₂-reinforced hybrid composites decreased in the temperature range of 30−100 °C due to the combined lubrication offered by the wear protective layer and its solid lubricant phase. Scanning electron microscopy (SEM) observation of the worn pin surface revealed severe adhesion, delamination, and abrasion wear mechanisms at temperatures of 150, 200, and 250 °C, respectively. At 150 °C, transmission electron microscopy (TEM) observation of the hybrid composites revealed the formation of deformation bands due to severe plastic deformation and fine crystalline structure due to dynamic recrystallization.     

原位合成Al_3Ti颗粒增强铝基复合涂层(英文)

以直径200μm、纯度99.5%的钛丝丝网为反应源,通过熔渗-原位反应法制备一种Al3Ti金属间化合物颗粒增强铝基表面复合涂层。差热分析结果表明,在890°C下,Ti丝和Al熔体间发生反应。采用XRD、SEM以及显微硬度和磨损测试对所得到的复合涂层进行表征。结果表明:当保温时间为20min时,钛丝反应完全,原位合成为块状和条状的Al3Ti颗粒;颗粒的显微硬度大约为基体显微硬度的4.5倍;在载荷10N的干滑动磨损条件下,与没有增强的Al基体相比较,保温20min所制备的复合涂层表现出较好的耐磨性,其磨损机制为粘着磨损和磨粒磨损共存。     

Influence of TiB2 addition on friction and wear behaviour of Al2024-TiB2 ex-situ composites

Present work encapsulated the friction and wear behaviour of aluminium matrix composites reinforced with different mass fractions of titanium diboride (TiB₂) particles, synthesized by stir casting. A pin on disc tribotester was employed for conducting the dry sliding wear tests of Al2024-TiB₂ composites. The tests were performed adopting various parameters like load, sliding distance and sliding velocity for investigating the effect of tribological parameters on the prepared composites. Microstructural characterization confirmed uniform dispersion of TiB₂ particles and good matrix-reinforcement bonding. Results of the experiments revealed that, low friction and wear rates were observed in the developed composites compared to Al2024 alloy, whereas wear rates of both Al2024 alloy and fabricated composites increased with the increase in load, sliding velocity and sliding distance. However, friction coefficient of both Al2024 alloy and fabricated composites reduced with the increase in applied load but rose with the increase in sliding velocity and sliding distance. SEM studies of the worn surfaces and debris depicted that enhancement in wear resistance can be ascribed to finer debris formation.