复合材料对LY12CZ铝合金C-环应力腐蚀性能的影响

采用铝合金C-环试样应力腐蚀试验方法，将碳纤维环氧复合材料与LYl2CZ铝合金相互偶接，研究由于电偶腐蚀的存在，对LYl2CZ铝合金应力腐蚀性能的影响，利用SEM方法对裂纹断口进行了分析。结果表明，复合材料与LYl2CZ铝合金的电偶腐蚀作用，促进了LYl2CZ铝合金C-环应力腐蚀裂纹形成与扩展，电偶作用使晶粒表面的点蚀减少，晶界腐蚀的溶解速率明显加快，晶界的二次裂纹大大增加，而与铝合金偶接的复合材料表面形貌基本无变化。     

材料微生物腐蚀的研究概况

综述了国内外近几十年来对铁、碳钢、不锈钢等一般金属材料,铝、铜、镍、钛及其合金等有色金属材料和部分工业非金属材料的微生物腐蚀的研究概况.指出了目前材料微生物腐蚀的途径、机理和控制方法.     

航空铝合金原位腐蚀疲劳性能及断裂机理EI北大核心CSCD

为了研究不同腐蚀条件下2024铝合金的疲劳性能,首先设计搭建原位腐蚀疲劳平台,然后分别进行无腐蚀疲劳、预腐蚀疲劳和原位腐蚀疲劳实验,分析不同腐蚀疲劳条件下2024铝合金的疲劳断裂行为,最后利用扫描电镜(SEM)表征宏、微观断口特征,探究失效机理。结果表明:相同腐蚀环境和时间下,预腐蚀和原位腐蚀疲劳寿命分别为无腐蚀疲劳寿命的92%和42%;在原位腐蚀疲劳条件下,滑移带挤入、挤出导致表面粗糙度增加,吸附较多腐蚀介质,加剧蚀坑演化,易于裂纹萌生并形成多个裂纹源。裂纹的连通形成更大尺寸的损伤,并在材料内部快速扩展。预腐蚀和原位腐蚀疲劳试件断口观察到大量脆性疲劳条带,并且原位腐蚀疲劳条带平均间距约为无腐蚀疲劳条带间距的2倍,说明原位腐蚀疲劳条件下裂纹扩展速率更快。     

热电耦合对铝/钢连续驱动摩擦焊接头组织的影响机理

采用连续驱动摩擦焊技术焊接纯铝1060/Q235低碳钢异质接头,开展两个周期(30天/60天)热电耦合实验(静载392 N+高温300 ℃+直流60 A),研究热电耦合对铝/钢异质接头焊缝微观组织、力学性能及界面生长的影响。结果表明：原始态接头界面径向金属间化合物(IMCs)层厚度不均匀,中心区域无明显IMCs生成。热电耦合30天后界面中心生成宽度为0.3~0.5 μm且以颗粒状由钢侧向铝侧弥散分布的IMCs层,整体拉伸断裂在铝母材的热力影响区。热电耦合60天后IMCs层与钢侧之间出现腐蚀沟槽,IMCs破碎,钢侧无裂纹产生,铝侧形成大量由IMCs层向铝母材内部扩展的裂纹和孔洞,焊缝及裂纹尖端处成分偏析,整体拉伸断裂在焊缝处。界面腐蚀和失效速率与界面IMCs层的厚度成正比,即v_center＜v_1/2R＜v_2/3R。由于原始态接头界面组织不均匀以及热电耦合实验过程中界面不同位置组织生长速率的差异,使得热电耦合后接头界面2/3R位置出现不同断裂形貌的分界线,2/3R内侧以准解理断裂方式为主,2/3R外侧为韧窝断裂和准解理断裂的综合结果。     

形变对LY12铝合金应力腐蚀开裂性能的影响

本文研究了不同的形变时效处理对LY12铝合金应力腐蚀开裂性能的影响。利用扫描电镜和透射电镜观察了各种形变时效状态试样应力腐蚀开裂的断口形貌及其微观组织,探讨了形变提高LY12铝合金应力腐蚀开裂抗力的原因。     

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.     

升温时效处理7075铝合金在含SRB模拟海水中的应力腐蚀行为

7系铝合金是一种可热处理强化的铝合金,通过改变热处理工艺的方法可以提高铝合金的抗应力腐蚀性能.本文研究了不同升温时效处理下,铝合金在含硫酸盐还原菌(SRB)模拟海洋溶液中的应力腐蚀行为,并通过应力-应变曲线和断口形貌,对比分析了铝合金在无菌溶液和SRB溶液中的应力腐蚀行为差异.研究表明,升温时效处理可以提高合金的自腐蚀...     

铝-钛-钢爆炸复合板在不同海域的腐蚀行为

根据铝-钛-钢爆炸复合板的应用环境,将其投放在青岛、舟山和厦门3个海域的潮差区和飞溅区,暴露1年、4年后对材料腐蚀行为进行研究。结果表明：该复合板在3个海域的腐蚀均以电偶腐蚀为主,铝层（1060）腐蚀程度比较严重,特别是在复合板侧面铝与钛交界处的铝,其腐蚀程度最为严重,形成很深的沟槽;3个海域暴露时间与腐蚀深度不为线性关系,而是随着时问的延长腐蚀变得缓慢;3个海域潮差区的试样正面腐蚀程度的大小顺序是舟山〉青岛〉厦门,侧面的腐蚀程度大小顺序是厦门〉青岛〉舟山;飞溅区的试样正面腐蚀程度的大小顺序是厦门〉青岛,侧面腐蚀程度顺序大小是青岛〉厦门。     

THE EFFECT OF ENVIRONMENT ON FATIGUE CRACK GROWTH BEHAVIOR OF 2021 ALUMINUM ALLOY

Abstract— The effects of dry hydrogen, moist air, distilled water and hydrazine environments on the fatigue crack propagation behavior of 2021 aluminum alloy have been investigated over a wide range of growth rates spanning about six orders of magnitude. Environmental interactions in the intermediate and near-threshold crack growth regions are shown to be associated with different fracture characteristics and mechanisms. Scanning Auger and X-ray photoelectron spectroscopic analysis of fracture surface corrosion deposits revealed that oxide induced crack closure phenomena, which considerably influence the near threshold corrosion fatigue behavior of low strength steels and some aluminum alloys, are not of importance for the present 2021-T6 aluminum alloy. The mechanistic aspects of environmentally influenced fatigue behavior of the alloy are discussed in the light of hydrogen embrittlement, chemical reactions and crack closure concepts.     

Fracture Behavior of GMA Welded Joints of Dissimilar and Similar Aluminum Alloys of 6061-T6/5083-O

Aluminum alloys of grade 6xxx and 5xxx are used where strength and corrosion resistance both are important. This paper reports the GMA welding of dissimilar 6061 T6 and 5083 O aluminum alloys and comparison of mechanical properties and fracture behavior of dissimilar joints (6061 T6-5083 O) with similar joints of the two base materials (6061 T6-6061 T6 and 5083 O-5083 O). GMA welding is used mostly due to high deposition rate, deeper penetration and high welding speed. The fusion welding of dissimilar aluminum alloys faces many problems due to the different chemical compositions and thermal conductivities of aluminum alloys. The dissimilar joint exhibited an average tensile strength of 138 MPa and weld hardness of 74.2 VHN. The scanning electron micrograph of tensile fracture surface was obtained to investigate the mode of failure. The fractograph at top portion of the fractured surface of 6061 T6-6061 T6 joints exhibited smaller grain size and smaller spacing between grains. The fractograph at middle portion showed population of dimples, which is the indication of ductile type of fracture. The fractograph at bottom portion (root region) indicated relatively smaller cleavage facets in similar joint of 5083 O-5083 O.     

7055铝合金的研究现状及展望

7055铝合金是目前超高强铝合金中强度较高且断裂韧性和耐腐蚀性能较好的一种新型变形铝合金.概述了微量元素对7055铝合金组织和性能的影响,介绍了该合金的热处理工艺,阐述了其微观组织结构、加工性能以及神经网络在该合金研究中的应用.并针对7055铝合金目前存在的问题,提出了今后研究的方向.     

Research on corrosion performance of 6061 aluminum alloy in salt spray environment

Salt spray corrosion test was carried out on 6061 aluminum alloy, and quasi-static tensile test at room temperature was carried out on the sample with universal testing machine. The effect of salt spray corrosion on the mechanical properties of 6061 aluminum alloy was studied by scanning electron microscope (SEM), energy dispersive spectrometer (EDS) and electrochemistry. The corrosion rate of 6061 aluminum alloy was quantitatively characterized by different corrosion parameters. It was found that local corrosion of 6061 aluminum alloy occurred in salt spray environment, mainly pitting corrosion and intergranular corrosion. With the increase of corrosion time, the polarization resistance of 6061 aluminum alloy decreases, and the corrosion rate significantly increases. The average corrosion rate and the maximum corrosion rate of 6061 aluminum alloy were characterized by corrosion weight loss and corrosion pit depth. And they can be transformed into each other. The mechanical properties of 6061 aluminum alloy were mainly affected by the depth of corrosion pit. With the increase of corrosion time, the tensile strength and fracture strain decreased, resulting in poor plasticity of the sample. At the same time, the change of elongation of 6061 aluminum alloy can be accurately predicted by the depth of corrosion pit.     

2195铝锂合金搅拌摩擦焊接头盐雾腐蚀行为研究

本文研究了厚度为8 mm的2195铝锂合金母材及搅拌摩擦焊接头在3.5wt.％NaCl介质中的盐雾腐蚀行为,计算了不同腐蚀周期下的腐蚀速率,并通过OM、SEM、TEM观察分析母材与焊核区的腐蚀微观形貌.结果 表明:2195铝锂合金母材及搅拌摩擦焊接头在3.5％ NaCl腐蚀介质中的主要腐蚀形式为点蚀,随时间的延长发展为...     

Al-Cu-Mg-Ag合金与ZL205A合金性能与微观组织对比

采用半连续铸造法分别制备了Al-Cu-Mg-Ag合金与ZL205A合金。对两种铝合金的流动性能、室温及高温拉伸性能、拉伸断口形貌、晶间腐蚀性能和微观组织进行了对比分析。结果表明:浇铸温度为720℃和740℃时,Al-Cu-Mg-Ag合金的流动性能均优于ZL205A合金的。室温、150℃、200℃、250℃下,Al-Cu-Mg-Ag合金的强度均高于ZL205A合金的,且随着温度的升高,其强度降低的幅度要明显低于ZL205A合金的,两种材料的室温伸长率基本相当。Al-Cu-Mg-Ag合金的晶间腐蚀深度在182～246 μm之间,优于ZL205A合金的274～337 μm。Al-Cu-Mg-Ag合金无析出带的宽度要窄于ZL205A合金的。      

合金元素对镍铝青铜性能的影响

介绍了海水泵用材料镍铝青铜的主要性能 ,重点讨论了合金元素对镍铝青铜材料的腐蚀性能、金相组织和铸造工艺性能的影响 ,提出了改进铸造镍铝青铜耐腐蚀性能及铸造工艺性能的几点建议     

Corrosion of aluminum electrodes in aqueous slurries for lithium-ion batteries

Current manufacturing methods for lithium ion batteries use a non-aqueous solvent for producing slurries of cathode active materials and applying them to the aluminum current collectors. Transition to a water-based process may be desirable to reduce volatile organic compound emissions and costs, and increase processing efficiency. This transition may lead to additional complexities such as corrosion that could impact the performance of cells in service. The current work shows that the use of aqueous-based slurries for manufacturing lithium ion batteries can lead to general and pitting corrosion of the aluminum alloy foils used as current collectors with contact times as short as 100 s. Pitting corrosion initiates due to localized galvanic cells between cathodic intermetallic particles present in the aluminum alloy and the locally anodic aluminum matrix. The extent of pitting and amount of general corrosion product formed differs when using slurries of different active material compositions and increases with slurries of higher inherent pH. The presence of the intermetallic particles in the aluminum alloy is expected based on the chemical composition of the material. While elimination of the intermetallics from the aluminum is possible by increasing the purity of the material, it is unlikely that this mitigation strategy would be implemented due to economic considerations.     

A review of selective laser melting of aluminum alloys: Processing,microstructure, property and developing trends

Selective laser melting (SLM) is an attractive rapid prototyping technology for the fabrication of metallic components with complex structure and high performance. Aluminum alloy, one of the most pervasive structural materials, is well known for high specific strength and good corrosion resistance. But the poor laser formability of aluminum alloy restricts its application. There are problems such as limited processable materials, immature process conditions and metallurgical defects on SLM processing aluminum alloys. Some efforts have been made to solve the above problems. This paper discusses the current research status both related to the scientific understanding and technology applications. The paper begins with a brief introduction of basic concepts of aluminum alloys and technology characterization of laser selective melting. In addition, solidification theory of SLM process and formation mechanism of metallurgical defects are discussed. Then, the current research status of microstructure, properties and heat treatment of SLM processing aluminum alloys is systematically reviewed respectively. Lastly, a future outlook is given at the end of this review paper.     

Hot Sheet Metal Forming Strategies for High-Strength Aluminum Alloys: A Review—Fundamentals and Applications

In the past decade, aluminum alloys have become important structural materials in the automotive industry, thanks to their low density, high strength, high fracture toughness, and good fatigue performance. However, an important limitation of aluminum alloys is their poor formability at room temperature; as a result, numerous studies have been conducted with the aim of developing forming techniques to overcome this and facilitate the forming of more complex-shaped components. Following an overview on the metallurgical background of aluminum alloys, this article reviews recent developments in forming processes for aluminum alloys. The focus is on process variants at room temperature and at higher temperatures and on a new hot forming technique promising considerable improvements in formability. This review summarizes the influence of different process parameters on microstructures and mechanical properties. Particular emphasis is given to process design and to the underlying microstructural phenomena governing the strengthening mechanisms.     

Recent Progress in Corrosion and Protection of Magnesium Alloys

Magnesium alloys are advanced light structural and functional materials being increasingly used in the automotive, aerospace, electronic, and energy industries. However, their corrosion performance at the current stage of development is still not good enough for increasingly diverse practical applications. The Cooperative Research Centre for Cast Metals Manufacturing (CAST) in Australia is one of the most active research organizations in the world established to cope with the problems associated with the development and application of advanced light metals. Corrosion and prevention of magnesium and its alloys is an important part of CAST's research program. This paper presents a brief summary of recent research achievements by CAST and relevant research work in this area in the world. This overview covers “anodic hydrogen evolution”, estimation of corrosion rate, corrosion of aluminum‐ and non‐aluminum‐containing magnesium alloys, influences of composition and microstructure on corrosion, corrosion of a die‐cast magnesium alloy, galvanic corrosion, coolant corrosion, and an aluminum‐alloyed coating. The aim of this overview is to deepen the current understanding of corrosion and protection of magnesium and its alloys and to provide a base for future research work in this field.     

Influence of grain-boundary pre-precipitation and corrosion characteristics of inter-granular phases on corrosion behaviors of an Al–Zn–Mg–Cu alloy

In this paper the influence of high-temperature pre-precipitation treatment on corrosion behaviors of 7055 aluminum alloy is investigated. High-temperature pre-precipitation treatment enhances the discontinuing distribution of the coarse precipitates along the grain boundary, and increases the Cu content of grain-boundary precipitates, which obviously improves stress corrosion resistance, suppresses the serve fracture of sub-grain boundary under the stress corrosion and reduces inter-granular corrosion (IGC) susceptibility with the same strength and ductility. The electrochemical corrosion results of inter-granular phases indicate that the Cu-rich, discrete and coarse grain-boundary precipitates and the decreasing potential difference among inter-granular phases in the grain boundary are responsible for the enhancement of corrosion resistance of 7055 alloy.