Two-dimensional Corrosion Pit Initiation and Growth Simulation Model

A two-dimensional corrosion initiation and growth model for aircraft aluminum materials is developed. The model takes into account the electro-chemical parameters as well as specific rules governing corrosion mechanisms. The simulation program is implemented in a cellular automata framework. The corrosion initiation and growth patterns obtained from simulations are compared qualitatively and quantitatively to the experimental data obtained from the Center for Materials Diagnostics at the University of Dayton Research Institute, Dayton. The results indicate that the present model effectively captures the corrosion damage process including initiation and growth. The effects of various electro-chemical parameters on the damage growth obtained from the simulation are presented and discussed. The results presented illustrate a new approach to modeling corrosion damage in aircraft aluminum materials. The simulation program is developed in a JAVA environment for ease of portability and usability.     

Effect of Trace Sn on Pitting Behaviors of High Voltage Anode Aluminum Foil

The effect of trace Sn on the pitting morphology of high voltage anode aluminum foils was investigated. The distributions of microelement Sn, Fe, Si, Cu and Mg in the surface layer of aluminum foils with different Sn content were determined by using a secondary ion mass spectrometer. It was found that the micro-alloyed Sn is enriched at the external surface. The mechanism of pitting behavior of trace Sn on aluminum surface is similar with that of lead. Enrichment of Sn in the surface layer provides large numbers of sites for initiation of pitting corrosion, while pitting sites appeared relatively inhomogenously in the foils without Sn. Sn, as an eco-friendly microelement, can be applied to replace Pb in improving the homogenous pitting behaviors of high voltage aluminum foils, in which the volume fraction of cube texture is not reduced.     

超高纯氯气的大规模产业化生产

超纯氯是半导体、光纤生产的重要原材料。近年来我国的半导体、光纤工业已从研究向产业化发展,作为重要电子气体的超纯氯将发挥重要的作用。为确保产品质量稳定、降低成本,对该产品进行产业化生产十分必要。     

Influence of Al7Cu2Fe intermetallic particles on the localized corrosion of high strength aluminum alloys

The development of aluminum alloys of the Al–Zn–Mg–Cu system is the primary factor that enabled the evolution of aircraft. However, it has been shown that these alloys tend to undergo pitting corrosion due to the presence of elements such as iron, copper and silicon. Thus, the purpose of this study is to evaluate the behavior of the Al₇Cu₂Fe precipitate in 7475-T7351 and 7081-T73511 alloys based on microstructural characterization and polarization tests. The corrosion and pitting potentials were found to be very similar, and matrix dissolution occurred around the Al₇Cu₂Fe precipitate in both alloys, revealing the anodic behavior of the matrix.     

Environmental effect on the fatigue performance of bare and oxide coated 7075-T6 alloy

Fatigue behaviors of bare and anodic oxide coated 7075-T6 alloy have been investigated in laboratory air and 3.5%NaCI solution environment by using smooth cylindrical specimens. Presence of corrosive attack during fatigue test drastically reduced fatigue performance of the alloy. The deleterious effect was observed to be pronounced at high-cycles fatigue region, where the fatigue strength of the bare specimen was lowered by a factor of 2.9. However, the oxide coated specimens having a thickness of 23 μm showed a modest reduction in fatigue strength. Corrosion fatigue (CF) strength of the bare specimens was predominantly controlled by pitting-induced crack nucleation. Examinations on the surfaces of the corrosion-fatigued and immersed test specimens revealed that cyclic loading stimulated corrosion pit formation during CF tests. Also, corrosion behaviors of both the coated and bare specimen shave been investigated by potentiodynamic test. Despite superior corrosion resistance of coated specimens, fatigue performance was adversely affected under the combined action of corrosion attack and cyclic loading.     

超高强铝合金中杂质元素的研究现状

综述了超高强铝合金中Fe、Si等杂质元素的存在形式以及对合金组织、拉伸力学性能、断裂韧性和抗腐蚀性能的影响,总结了Fe、Si等杂质元素的控制标准,概述了通过熔体净化、添加稀土元素、采用粉末冶金等新型制备工艺减小杂质元素影响的研究进展.     

超高强铝合金中杂质元素的研究现状

综述了超高强铝合金中Fe、Si等杂质元素的存在形式以及对合金组织、拉伸力学性能、断裂韧性和抗腐蚀性能的影响,总结了Fe、Si等杂质元素的控制标准,概述了通过熔体净化、添加稀土元素、采用粉末冶金等新型制备工艺减小杂质元素影响的研究进展.     

Research Status on Impurities in Ultra High Strength Aluminum Alloys

综述了超高强铝合金中Fe、Si等杂质元素的存在形式以及对合金组织、拉伸力学性能、断裂韧性和抗腐蚀性能的影响,总结了Fe、Si等杂质元素的控制标准,概述了通过熔体净化、添加稀土元素、采用粉末冶金等新型制备工艺减小杂质元素影响的研究进展.     

高纯铝多向锻造大塑性变形过程的数值模拟及实验研究

采用多向锻造的方法研究室温下锻造道次对高纯铝组织的影响,并用三维DEFORM软件对实验过程进行模拟。结果表明:经3次多向锻造后,高纯铝试样横截面上形成1个X形的细晶区及4个粗晶区,随锻造道次增至9,细晶区的面积不断扩大,粗晶区的面积不断缩小,但细晶区与粗晶区的晶粒尺寸差异并未消除。当高纯铝试样心部的等效应变量达到2.5时,心部再结晶晶粒尺寸达到70μm,继续增加心部的等效应变至6.0,心部的晶粒不再随等效应变量的增加而细化,达到晶粒细化的极限。而当试样边部难变形区和自由变形区的等效应变量增至4.0时,其再结晶晶粒仍随等效应变量的增加而细化,未达到晶粒细化极限。这表明局部等效应变量及局部变形方式均是影响高纯铝晶粒细化的重要因素。     

电子束真空精炼直接定向凝固制备高纯铜的研究

以电子束真空熔炼直接定向凝固技术制备5N高纯铜大铸锭为研究目标,利用电子束熔炼原材料,熔体直接定向凝固后得到高纯铜铸锭.采用GDMS-VG9000辉光放电质谱仪和TCH600氧氢分析仪研究了金属杂质及氧氢元素的去除效果,通过EPMA-1600电子探针研究了提纯后元素的分布情况.结果表明:真空电子束熔炼直接定向凝固技术可将原料为4N(99.9988711％)的电解阴极铜板,制备出纯度5N(99.9997235％)、Φ59 mm大尺寸高纯铜铸锭,杂质元素总量降低了75.506％,中间凝固组织为单晶;五种含量较高的元素Ag、Cu、O、P和S均匀分布,没有出现杂质的偏聚现象;与原材料相比,0、H元素分别降低了86.47％,85.00％.研究表明真空电子束精炼直接定向凝固技术能够制备氧氢含量较低的5N大尺寸高纯铜铸锭.     

超高强铝合金研究进展

超高强铝合金具有很高的强度和韧性,是航空航天领域极具应用前景的结构材料.评述了超高强铝合金的国内外发展情况,论述了铝合金的强化技术和方法,并就今后的研究开发提出了建议.     

镁合金微弧氧化制备生物涂层及细胞毒性研究

评价微弧氧化工艺制备的镁合金生物钙磷陶瓷涂层材料的生物安全性,细胞毒性评价是重点研究对象。利用微弧氧化电源,在恒流条件下制备含有双相钙磷成分的涂层试样,通过MTT比色法对该试样细胞毒性进行测定分析,并论证了试样在不同浸渍比例时对细胞毒性的影响。结果表明各试验时间组毒性安全为“0”级,无细胞毒性,且不同浸渍比例对细胞毒性无影响。结论：所制备镁合金涂层生物材料在生物毒性评价中属于无毒性材料,具有良好生物相容性。     

全铝车身的发展与探索

本文从全铝车身使用材料的强化及性能特点入手,通过与铜构车身的对比,分析了其优缺点,研究了目前消费现状,指出了发展趋势,做出了市场前景分析。     

耐高温、抗油污海水铝合金牺牲阳极的研究

通过正交实验 ,研究了Al Zn In Si Zr铝合金牺牲阳极在常温、中温、高温海水和常温油污海水中的性能 ,并探讨了其作用机理     

耐高温，抗油污水铝合金牺牲阳极的研究

通过正交实验,研究了Al-Zn-In-Si-Zr铝合金牺牲阳极在常温、中温、高温海水和常温油污海水中的性能,并探讨了其作用机理。     

投影管用高亮度高分辨率三英寸YAG荧光屏

介绍一种用于投影管的新型YAG荧光屏。该屏的对角线尺寸为 3英寸 ,是采用离心沉淀法将荧光粉沉积在单晶YAG衬底上制作而成。YAG衬底具有热导率较高、熔点较高、透明度好和机械强度好 (相对于传统玻璃衬底 )等性能 ,因而采用该YAG荧光屏可实现高亮度、高分辨率、高对比度的大屏幕投影电视图像显示。在 0 5mA阴极电流下 ,3英寸YAG荧光屏5 0 %光斑尺寸仅 85 μm ,在 1 0mA阴极电流和 2 9kV阳极电压下 ,红、绿、蓝的亮度分别为 6 2× 10 4,1 4× 10 5 ,8 3× 10 3cd/m2 。     

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     

铝合金阳极化二重封闭工艺的研究EI

本文论述了铝合金阳极氧化二重封闭工艺及封闭膜层的性能，并对二重封闭膜层比重铬酸钾膜层抗蚀能力有明显提高进行了分析。     

铝合金高温储热材料及储热系统设计

对Al-7％Si合金,Al-7％Si-4％Cu合金和Al-33％Cu合金进行了差热扫描分析,设计了高温储热系统,并建立了相应的测试与评价方法。结果表明,3种合金的熔化潜热分别为305．5J／g,245．1J／g和202．7J／g,且Al-Si合金的相变潜热与含铝量成正比关系。该测试与评价方法可对储热材料的储热性能和储热系统的换热效率,热交换动力学等指标进行综合评价。     

Electrochemical Deposition and Nucleation of Aluminum on Tungsten in Aluminum Chloride-Sodium Chloride Melts

Electrochemical deposition and nucleation of aluminum on tungsten electrode from AlCl3-NaCl melts were studied by cyclic voltammetry, chronopotentiometry and chronoamperometry. Cyclic voltammetry and chronopotentiometry analyses showed that Al （Ⅲ） was reduced at 200℃ in two consecutive steps in an electrolyte of molten AlCl3-NaCl system with a composition 52：48 molar ratio. The current-time characteristics of nucleation aluminum on tungsten showed a strong dependence on overpotentials. Chronoamperometry showed that the deposition process of aluminum on tungsten was controlled by an instantaneous nucleation with a hemispherical diffusion-controlled growth mechanism. The results could lead to a better understanding of the AlCl3-NaCl melt system that has technological importance in electrodeposition of metals as well as in rechargeable batteries.