共查询到19条相似文献,搜索用时 140 毫秒
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采用非真空轧制非对称组坯方式在不同总压下率(28%~70%)下制备Q235碳钢/304不锈钢复合板,研究了复合板界面处的组织、夹杂物形貌、硬度和剪切强度,探讨了界面夹杂物与脱碳层对界面结合强度的竞争性影响.结果表明:随着轧制总压下率的增加,复合板界面夹杂物由集中分布的块状变为均匀分布的颗粒状;当轧制总压下率由28%增大到47%时,影响复合板界面结合强度的主要因素是界面夹杂物,增加轧制压下率有利于提高界面结合强度;当轧制总压下率由47%增大到70%时,不锈钢侧晶粒尺寸急剧减小,碳钢侧脱碳层厚度增加,界面结合强度降低,脱碳层成为影响结合强度的主导因素.可以通过合理控制轧制压下率来平衡界面夹杂物和脱碳层对结合强度的竞争性影响. 相似文献
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为提高柴油机铝合金活塞的可靠性和耐用性,在不同电源占空比下通过微弧氧化实验在铝合金基体上制备得到微弧氧化陶瓷层,利用电泳技术将MoS_2微纳米粒子引入陶瓷层的孔隙中,制备得到陶瓷基自润滑复合涂层。研究微弧氧化电源占空比对陶瓷层和复合涂层微观形貌、厚度和表面粗糙度的影响,并利用往复式摩擦磨损试验机在干摩擦、油润滑条件下对复合涂层的摩擦学性能进行分析。结果表明:随占空比的提高,微弧氧化陶瓷层的厚度、表面粗糙度呈现先增加后减小的变化趋势;随占空比的提高,制备得到的复合涂层的摩擦因数先减小后增大,占空比为60%~70%得到的复合涂层摩擦因数最低,且复合涂层与基体结合状态好,抗磨自润滑性能显著。 相似文献
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微弧氧化技术是铝合金材料表面改性的一项重要技术。通过微等离子体的高温高压作用,使所生成的微弧氧化膜具有膜层厚、硬度高、耐磨、耐蚀、耐压绝缘以及抗高温冲击等优异特性,在军事、航天、航空、纺织、机械、汽车、石油、化工及医疗等工业部门有着广阔的应用前景,特别适用于高速运转且有耐磨要求的铝合金零件的表面处理;因此,铝合金表面微弧氧化涂层制备影响因素的研究和分析对铝合金材料表面改性结果的影响与发展有重大意义。在总结铝合金表面微弧氧化涂层制备的影响因素的基础上,分析讨论了不同因素对铝合金表面微弧氧化涂层制备的影响。通过选择合理的工艺参数可以获得综合性能良好的陶瓷膜层。 相似文献
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碳纳米管添加剂对ZL109铝合金微弧氧化陶瓷层的生长及耐磨性能影响 总被引:1,自引:0,他引:1
为进一步提高ZL109铝合金的耐磨性能,在微弧氧化电解液中加入碳纳米管添加剂,探究碳纳米管对ZL109铝合金微弧氧化陶瓷层生长及耐磨性能的影响。在电解液中分别加入0.4~2 g/L碳纳米管,在双极性脉冲恒压模式下制备得到ZL109铝合金微弧氧化陶瓷层;从表面特征、微观形貌、厚度、物相组成等方面进行陶瓷层生长行为的分析,并利用往复式摩擦磨损试验机探讨陶瓷层的耐磨性能。结果表明:碳纳米管电解液添加剂对陶瓷层生长过程影响较大,显著改变了陶瓷层的基本特征,使得原有表面的孔隙率和孔径显著下降,但过高的碳纳米管浓度会导致表面出现显著的不均匀的突起;碳纳米管未直接参与陶瓷层成膜,而是通过自身的较高的存储介电微充电能力影响了微弧放电过程中单位通道面积内生成的氧化产物的量,从而对陶瓷层各项特征产生显著的影响;添加碳纳米管后陶瓷层摩擦因数有所增大,但耐磨性能大幅提升,其中添加1.2 g/L碳纳米管制备得到的陶瓷层具有较好的耐磨性能,具有较低且稳定的摩擦因数。 相似文献
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采用液态搅拌法制备SiCp/ZL101复合材料,研究了SiC颗粒含量对材料抗拉伸强度和硬度的影响规律,同时还研究了固溶温度和时效温度对材料硬度的影响规律。结果表明,在本试验的SiC颗粒含量范围内,SiC颗粒含量越高,SiCp/ZL101复合材料的抗拉强度越高,伸长率越低;在排除缺陷等外来影响因素的条件下,SiCp/ZL101复合材料的硬度随着SiC含量的增加而提高。 相似文献
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为研究铝合金/碳纤维预浸料轧制制备层板的可行性及力学性能,基于铝板不同表面处理工艺和轧制压下量,制备了碳纤维增强铝合金层板。结合三点弯曲试验分析了表面处理工艺和压下量对层板弯曲力学性能的影响。结果表明:铝合金表面处理工艺和轧制压下量对层板力学性能影响显著,经阳极氧化工艺处理后所得层板弯曲性能改善最为明显,弯曲强度和模量分别为573 MPa和80.9 GPa,相比表面未处理试样分别增加了65.9%和39.1%,界面结合性能明显优于化学清洗法和机械打磨法,层板破坏形式由纤维整体断裂和分层失效转变为纤维屈曲变形;当压下量为6.5%时,铝合金/纤维树脂界面整洁平齐,层板弯曲性能最优,表明适当的轧制压力有利于树脂流动浸润纤维,压实层间孔隙,促进树脂与铝合金表面形成稳定的机械咬合结构。 相似文献
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配制蛇纹石纳米粒子分散液,选定不同质量浓度分散液加入电解液中,分别对ZL109铝合金试件进行微弧氧化处理,制备蛇纹石纳米粒子复合微弧氧化陶瓷膜。通过测厚仪和显微硬度计对复合陶瓷膜进行检测得到表面性能最佳的试件,并在摩擦磨损试验机上考察该试件的摩擦学性能;通过分析其截面形貌和磨损前后表面形貌,探讨其摩擦机制。结果表明,蛇纹石纳米颗粒的加入使微弧氧化复合陶瓷层的膜厚增加、硬度升高,且蛇纹石纳米颗粒存在最佳添加量,使复合陶瓷膜试件具有较高的厚度和硬度;蛇纹石纳米颗粒的加入降低了复合陶瓷膜摩擦因数,改善其磨损性能。在摩擦过程中,蛇纹石对表面孔隙进行了填充,使表面的粗糙度减小;同时,蛇纹石在摩擦形成了类似薄膜的块状,起到了自修复的作用。 相似文献
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《机械工程学报(英文版)》2020,(2)
Selective laser melting(SLM) is an emerging additive manufacturing technology for fabricating aluminum alloys and aluminum matrix composites. Nevertheless, it remains unclear how to improve the properties of laser manufactured aluminum alloy by adding ceramic reinforcing particles. Here the effect of trace addition of TiB_2 ceramic(1% weight fraction) on microstructural and mechanical properties of SLM-produced AlSi10Mg composite parts was investigated. The densification level increased with increasing laser power and decreasing scan speed. A near fully dense composite part(99.37%) with smooth surface morphology and elevated inter-layer bonding was successfully obtained. A decrease of lattice plane distance was identified by X-ray di raction with the laser scan speed decreased, which implied that the crystal lattices were distorted due to the dissolution of Si and TiB_2 particles. A homogeneous composite microstructure with the distribution of surface-smoothened TiB_2 particles was present, and a small amount of Si particles precipitated at the interface between reinforcing particles and matrix. In contrast to the Al Si10 Mg alloy, the composites showed a stabilized microhardness distribution. A higher ultimate tensile strength of 380.0 MPa, yield strength of 250.4 MPa and elongation of 3.43% were obtained even with a trace amount of ceramic addition. The improvement of tensile properties can be attributed to multiple mechanisms including solid solution strengthening, load-bearing strengthening and dispersion strengthening. This research provides a theoretical basis for ceramic reinforced aluminum matrix composites by additive manufacturing. 相似文献
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Most researches on micro-arc oxidation mainly focus on the application rather than discovering the evolution of residual stresses. However, residual stresses in the surface coatings of structural components have adverse effects on their properties, such as fatigue life, dimensional stability and corrosion resistance, etc. The micro-arc oxidation ceramic coatings are produced on the surfaces of 6061 aluminum alloy by a homemade asymmetric AC type of micro-arc oxidation equipment of 20 kW. A constant current density of 4.4___0.1 A/dm2 and a self-regulated composite electrolyte are used. The micro-arc oxidation treatment period ranges from 10 min to 40 min, and the thickness of the ceramic coatings is more than 20 Bin. Residual stresses attributed to 7-A1203 constituent in the coatings at different micro-arc oxidation periods are analyzed by an X-ray diffractometer using the sin2~u method. The analysis results show that the residual stress in the ceramic coatings is compressive in nature, and it increases first and then decreases with micro-arc oxidation time increase. The maximum stress value is 1 667_+20 MPa for period of 20 min. Through analyzing the coating thickness, surface morphology and phase composition, it is found that the residual stress in the ceramic coatings is linked closely with the coating growth, the phase composition and the micro cracks formed. It is also found that both the heat treatment and the ultrasonic action release remarkably the residual compressive stress. The heat treatment makes the residual compressive stress value decrease 1 378 MPa. The ultrasonic action even alters the nature of the residual stress, making the residual compressive stress change into a residual tensile stress. 相似文献
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The bonding of β'-Al2O3 and pyrex glass to Al matrix composites by anodic bonding process is achieved. The microstructure of the bonded interface and the joining mechanisms are analyzed with scanning electron microscope (SEM), energy dispersive X-ray fluorescence spectrometer (EDX). It is observed that the bonding region across the interface consists of the metal layer, oxide transitional layer and the ceramic layer, with the transitional layer composed of surface region and sub-surface region. The bonding process can mainly be categorized into anodic bonding process and solid state diffusing process. The pile-up of the ions and its drift in the interface area are the main reasons for anode oxidation and joining of the interface. The temperature, voltage and the drift ions in the ceramic or glass during the bonding process are the essential conditions to solid state diffusing and oxide bonding at the interface. The voltages, temperature, pressure as well as the surface state are the main factors that influence the anodic bonding. 相似文献
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G. G. Sozhamannan S. Balasivanandha Prabu 《The International Journal of Advanced Manufacturing Technology》2009,44(3-4):385-388
The quality of interface bonding between matrix and reinforcement is important in composite strengthening. Interface bonding strength of particulate reinforced metal matrix composites were investigated by joining process. The aluminum/silicon carbide specimens were prepared by different processing temperature with constant holding time. The structural morphologies have been evaluated by using scanning electron microscope and interfacial products were identified by using energy dispersive spectroscopy. The interface strength has been evaluated by tensile test and microhardness test. 相似文献