6061铝颗粒层增强7075铝基复合材料的微观结构及阻尼性能

采用热轧法制备出具有颗粒层状结构的6061p/7075铝基复合材料以改善7075铝合金的阻尼性能。通过OM、SEM、EDS和XRD分析6061p/7075层状铝基复合材料的微观组织,分别采用万能力学试验机和动态热机械分析仪分析其力学性能和阻尼行为。研究表明,6061铝颗粒层存在大量的颗粒间界面和微小孔隙,6061铝颗粒层与7075铝基体之间界面结合良好,没有发生界面反应;6061p/7075层状铝基复合材料最大抗拉强度为370.5 MPa,比7075铝基体提高了30%;6061p/7075层状铝基复合材料和基体材料的内耗值分别随着温度和应变量的升高而增大,复合材料的阻尼性能明显优于7075铝基体,在360℃时,复合材料的内耗值高达0.117,比7075铝基体提高了149%;6061p/7075层状铝基复合材料和基体材料的储能模量分别随着温度和应变量的升高而降低,在30℃时,复合材料的储能模量为38601 MPa,比7075铝基体高16%。      

SiCp／LY12铝基复合材料的阻尼行为

研究了ＳｉＣｐ／ＬＹ１２铝基复合材料及基基体铝合金的阻尼行为，发现随温度升高，铭基复合材料的阻尼性能显著增加，优于铝合金，并且增强物含量越多，合复合材料的阻尼性能越好。研究认为位错阻尼和界面阻尼是提高复合材料阻尼性能的原因。     

颗粒增强铝基复合材料阳极氧化与耐蚀性的研究

基体中加入与铝合金基体电位不同、高体积分数的碳化硅和石墨颗粒增强材料,可能导致材料的耐蚀性降低.采用盐雾腐蚀和硬质阳极氧化方法对4种喷射沉积制备的颗粒增强铝基复合材料和一种喷射沉积锭坯颗粒增强铝基复合材料的腐蚀行为及阳极氧化工艺进行了研究.结果表明,颗粒增强铝基复合材料具有较高的腐蚀率,腐蚀形态均为明显的点蚀;在适当阳极氧化工艺条件下,颗粒增强铝基复合材料表面可以制得优良耐蚀性的硬质阳极氧化膜.     

人工海水中铝合金与复合材料T700电偶的腐蚀性能

采用失重法、腐蚀电化学试验方法、电偶腐蚀试验方法,研究了铝合金(Al6061)在人工海水中的耐腐蚀性能和电化学特性及其与环氧碳纤维复合材料T700偶接后的电偶腐蚀敏感性.结果表明,Al6061在人工海水中有一定的电化学腐蚀钝化性;Al6061与T700偶接后,电偶腐蚀使Al6061的腐蚀速度明显加快,人工海水中通入空气使电偶腐蚀程度增大;在T700表面涂敷环氧树脂涂层,能有效控制T700与Al6061之间的电偶腐蚀.     

基体各类对混杂复合材料摩擦磨损性能的影响

研究了基体种类对SiC和石墨（Gr)颗粒混杂增强铝基复合材料的摩擦磨损性能的影响。各种铝基体的混杂复合材料的耐磨性有明显差异,纯铝基混杂复合材料具有最好的耐磨性,其次是A356,2024和6061为基体的混杂复合材料。     

基体种类对混杂复合材料摩擦磨损性能的影响

研究了基体种类对SiC和石墨(Gr)颗粒混杂增强铝基复合材料的摩擦磨损性能的影响.各种铝基体的混杂复合材料的耐磨性有明显差异,纯铝基混杂复合材料具有最好的耐磨性,其次是A356,2024和6061为基体的混杂复合材料.     

海水pH值对铝-空气-海水电池阳极性能的影响

为研究海水pH值升高对铝-空气-海水电池的铝阳极的腐蚀性能和放电性能的影响,以不同pH值的海水作为介质,采用极化曲线、交流阻抗、恒电流极化曲线和扫描电镜研究了铝合金在不同pH值海水中的腐蚀行为和放电行为。结果表明：随着pH值的升高,铝合金的自腐蚀电位逐渐降低,腐蚀速度加快;海水pH值的升高使铝合金的钝化区间变宽,当pH...     

增强颗粒与基体适配性对颗粒增强铝基复合材料强化机理的影响

用粉末冶金法制备了分别用Al2O3、SiC颗粒增强的颗粒体积分数为25%的6061Al基复合材料,在不同温度对其进行固溶-时效热处理,通过拉伸曲线分析和断口SEM分析研究了增强颗粒与基体适配性对颗粒增强铝基复合材料拉伸性能的影响。结果表明,低强度Al2O3颗粒不适合用于增强高强度的6061Al基体;研究了增强颗粒与基体适配性对颗粒增强铝基复合材料强化机制的影响,发现主要通过影响应力传递机制来影响复合材料性能;揭示了适配性与增强颗粒开裂、复合材料屈服之间的关系,得出增强颗粒相对于基体强度越高,颗粒开裂越少,并总结了一种表示增强颗粒与基体适配性关系的方法。     

新型铝合金阳极电化学性能与组织研究

研制了两种新型铝合金阳极材料；用恒电流方法和动电位方法测定了铝合金阳极在碱性氯化钠（25％KOH＋3．5％NaCl）介质中的电化学性能；用金相显微镜、扫描电子显微镜观察了新型铝合金的微观组织和阳级溶解后的表面腐蚀状态。结果表明：固溶于铝基体的微量合金化元素Ga、In及其适量均匀分布的第二相，可以破坏铝氧化膜的致密结构，促使铝基体的正常溶解，减少铝阳极极化，使铝合金阳极的稳定电极电位变得更负；加入能改变铝基体中杂质的存在状态和降低杂质含量的合金化元素Mg等，可以改善铝阳极的腐蚀均匀性，降低自腐蚀速度，提高阳极利用率。     

铝合金在乙二醇-水模拟冷却液中的腐蚀行为

目前,就铝硅合金在发动机冷却液中的腐蚀行为的研究未见深入报道。为此,利用失重、电化学阻抗和极化曲线等方法研究了AA6061铝合金在乙二醇-腐蚀水模拟冷却液体系中的腐蚀行为。结果表明,AA6061铝合金在乙二醇-腐蚀水溶液中存在2个腐蚀速率区间,初期腐蚀速率较低,随后腐蚀速率较高;在腐蚀反应开始时,乙二醇的吸附抑制了AA...     

Brazing of Aluminum Matrix Composite with Sn10Ag4Ti Active Filler Metal

The joining of 6061 aluminum matrix composites (6061 MMC) was conducted using a low temperature filler metal, Sn₁₀Ag₄Ti, in a vacuum of 1×10^-4torr. The results showed that Sn₁₀Ag₄Ti had superior wettability on the 6061 aluminum matrix composites surface. It was evident from the EPMA analyses of Sn₁₀Ag₄Ti brazements that a significant reaction zone could be observed at the 6061 aluminum matrix composites/filler metal interface. The Sn, Ag and Ti elements in the filler metal play different roles during the brazing. The good wetting behavior of the Sn₁₀Ag₄Ti/ monolithic 6061 alloy and Sn₁₀Ag₄Ti/Al₂O₃ system was suspected to cause the enhancement of the joint strength of the Sn₁₀Ag₄Ti/6061 MMC during the brazing.     

Effect of TiN particulate reinforcement on corrosive behaviour of aluminium 6061 composites in chloride medium

In the present investigation, the corrosive behaviour of Al 6061–TiN particulate composites prepared by liquid metallurgy has been studied in chloride medium using electroanalytical techniques such as Tafel, cyclic polarization and electrochemical impedance spectroscopy (EIS). Surface morphology of the sample electrodes was examined using scanning electron micrography and energy dispersive X-ray methods. X-ray diffraction technique was used to confirm inclusion of TiN particulates in the matrix alloy and identify the alloying elements and intermetallic compounds in the Al 6061 composites. Polarization studies indicate an increase in the corrosion resistance in composites compared to the matrix alloy. EIS study reveals that the polarization resistance (R _p) increases with increase in TiN content in composites, thus confirming improved corrosion resistance in composites. The observed decrease in corrosion rate in the case of composites is due to decoupling between TiN particles and Al 6061 alloy. It is understood that after the initiation of corrosion, interfacial corrosion products may have decoupled the conducting ceramic TiN from Al 6061 matrix alloy thus eliminating the galvanic effect between them.     

Mechanical properties of novel aluminum metal matrix metallic composites: Application to overhead conductors

The mechanical behavior and microstructural evolution of aluminum metal matrix metallic composites fabricated under various process conditions were investigated to understand their process-structure–property relations. The novel techniques for arranging the matrix and reinforcement materials and controlling the processing atmosphere were applied to the extrusion process. The composites were comprised of matrix 1050 and reinforcement 6061 aluminum alloys with varying percent weight compositions and were arranged in a tailorable concentric annular pattern. The composites were shown to substantially increase compressive strength when the atmosphere of composite arrangement was evacuated prior to extrusion. Mechanical response of the composites were compared to the pre-extruded 1050 and 6061 aluminum alloys. The yield strengths of each composite, with varying percent weight compositions, were found to lie between those of matrix and reinforcement alloys, and abided by a simple rule-of-mixtures when considering weight composition. Highly elongated grains were oriented in the as-extruded composites along the extrusion direction and grains near the interface between two constituent alloys showed higher aspect ratio than in the interior region. The present study could lead to the optimum composite design for various industrial applications including all aluminum alloy overhead conductors with high strength and improved electric conductivity.     

Effect of heat treatment on strength and abrasive wear behaviour of Al6061-SiC<Subscript>p</Subscript> composites

In recent years, aluminum alloy based metal matrix composites (MMC) are gaining importance in several aerospace and automobile applications. Aluminum 6061 has been used as matrix material owing to its excellent mechanical properties coupled with good formability and its wide applications in industrial sector. Addition of SiC_p as reinforcement in Al6061 alloy system improves its hardness, tensile strength and wear resistance. In the present investigation Al6061-SiC_p composites was fabricated by liquid metallurgy route with percentages of SiC_p varying from 4 wt% to 10 wt% in steps of 2 wt%. The cast matrix alloy and its composites have been subjected to solutionizing treatment at a temperature of 530°C for 1 h followed by quenching in different media such as air, water and ice. The quenched samples are then subjected to both natural and artificial ageing. Microstructural studies have been carried out to understand the nature of structure. Mechanical properties such as microhardness, tensile strength, and abrasive wear tests have been conducted both on matrix Al6061 and Al6061-SiC_p composites before and after heat treatment. However, under identical heat treatment conditions, adopted Al6061-SiC_p composites exhibited better microhardness and tensile strength reduced wear loss when compared with Al matrix alloy.     

铝基钎料在SiC及SiC_p/6061复合材料上的润湿性研究

对多种铝基钎料在SiC、6 0 6 1及SiCp 6 0 6 1复合材料上进行了润湿性试验。结果表明 :炉中钎焊时 ,钎料与钎剂的成分、加热温度与保温时间、钎料与钎剂熔化温度的匹配等是影响铝基钎料润湿性的主要因素 ;真空钎焊时 ,镁含量不同的各种含镁Al 2 8Cu 5Si钎料在Al基复合材料连接的温度范围内都不能润湿SiC陶瓷表面 ;配合QJ2 0 1钎剂 ,Al 2 8Cu 5Si 2Mg钎料对 15 %SiCp 6 0 6 1Al复合材料具有良好的润湿性 ,但对 30 %SiCp 6 0 6 1Al复合材料却润湿不良 ;在加钎剂的情况下 ,钎料中的镁反而对在铝合金及铝基复合材料上的润湿性有不利影响 ;在Al 2 8Cu 5Si 2Mg钎料和 15 %SiCp 6 0 6 1Al复合材料的钎焊界面处存在SiC颗粒的偏聚现象     

Encapsulation and microwave hybrid processing of Al 6061–Graphene–SiC composites

The demand for new aluminum alloy–based metal matrix composites with combinations of novel reinforcements, processed through innovative methods are very much needed for critical engineering applications. With this perspective, the current research work is aimed at the development of Al 6061 composites reinforced with two-dimensional Graphene nanoflake-encapsulated SiC. Ultrasonic liquid processing method is used to disperse the Graphene flake and the mixture is ball milled by adding SiC to achieve the encapsulation. Subsequently, the Al 6061 powder is added to the milled mixture and consolidated through uniaxial vacuum hot press followed by microwave hybrid sintering. Scanning electron microscope (SEM) analysis, X-ray diffraction analysis, hardness, density, and microstructure analysis were carried out on developed composites. Raman analysis was carried out to analyze the distortion on Graphene physical structure during various processing stages. Further, effects on novel combination of material with combined processing approach on flexural and tribological behavior have been analyzed.     

A physical model for the aging of an aluminum-base alloy reinforced with nitride particles

6061/X (X = AlN, Si₃N₄, TiN) aluminum-matrix composites have been prepared by a powder metallurgy process: by mixing aluminum alloy 6061 powder with nitride particles and extruding the mixture at high temperatures. After sintering and aging, the Vickers hardness of the composites has been measured. The results indicate that the Vickers hardness of the composites increases significantly with nitride particle content both before and after aging. The aging behavior of the composites can be interpreted in terms of a simple kinetic model, which was used earlier to predict changes in the yield strength of age-hardened unreinforced aluminum alloys. The model is shown to adequately describe the changes in the hardness of the composites. It is concluded that reinforcing nitride particles increase the precipitation rate, without influencing the nature of the precipitation process in the supersaturated solid solution.     

AlN颗粒在不同铝合金中的增强行为

LD2为了解AlN颗粒对不同强度等级的铝合金的增强效果及机制 ,对 40 %体积分数的AlN颗粒增强 10 70、10 6 1、LY12铝合金复合材料拉伸前后的微观组织进行了观察 ,发现拉伸前在基体中存在由热错配引起的高密度位错 ,在AlN颗粒的内部也存在大量的位错 ,拉伸后基体中的位错增殖 ,同时 ,AlN颗粒中的位错亦增多 .力学性能的测试结果表明 ,AlN颗粒对低强度、高塑性的L3纯铝增强率最高 ,中等强度、较高塑性的LD2铝合金不仅有较高的增强率 ,而且保持了一定的塑性 .AlN颗粒对基体的这种选择性主要与AlN颗粒在拉伸过程中产生微量变形 ,从而松弛部分界面应力有关 .LY12基体的塑性较低 ,易产生低应力断裂 ,因此 ,AlN颗粒的增强作用难以得到充分发挥 .