汽车轻量化用铝合金拼焊板的研究进展

基于节约能源和减少废气排放的需要,汽车轻量化已经成为世界汽车发展的主流。各种轻量化的技术和方法逐渐发展起来,材料轻量化和结构轻量化是汽车轻量化技术中的两个重要方面。材料轻量化即指使用铝、镁合金等密度更小的材料代替传统的钢铁材料达到减重的目的;而结构轻量化则是采用一些满足使用性能的新结构来实现减重。以铝合金为母材的拼焊板,能够同时满足材料轻量化和结构轻量化的要求,是拼焊板技术未来的发展方向。从焊接方法、成形性能研究、应用的主要障碍、以及未来的发展趋势等方面综述了汽车轻量化用铝合金拼焊板的研究进展。     

The USAMP magnesium powertrain cast components project

The U.S. Automotive Materials Partnership (USAMP) and the U.S. Department of Energy launched the Magnesium Powertrain Cast Components Project in 2001 to determine the feasibility of producing a magnesiumintensive engine—a six-cylinder engine with a magnesium block, bedplate, oil pan, and front cover. As the project approaches its midpoint, two goals are near completion: evaluation of the best available low-cost, creep-resistant magnesium alloys and design of engine components using the properties of the best alloys. Phase II of the project sets three additional goals: casting and testing the magnesium components in assembled powertrains, developing a powertrain magnesium alloy design database and common specification for magnesium powertrain alloys, and funding and promoting research to enable even more advanced powertrain applications in North America. Bob R. Powell is a technical fellow at General Motors Research & Development and Planning in Warren, Michigan.     

The USAMP magnesium powertrain cast components project

Despite the demonstrated ability of magnesium alloys to significantly reduce weight at acceptable costs in many areas of an automobile, powertrain components have not benefited from this metal, primarily because the high-temperature alloys that are required for engines and transmissions are too expensive. However, the U.S. Department of Energy and the U.S. Automotive Materials Partnership have launched a project to evaluate several new, potentially low-cost magnesium alloys, design several pre-competitive power-train components for the best alloy properties, cast and dynamometer or vehicle test the components in assembled powertrains, develop a powertrain magnesium alloy design database and common alloy specification, and identify andpromote the funding of fundamental research into improved magnesium alloys and casting processes.     

镁合金表面可降解聚合物改性涂层研发及应用

相比于钛合金、不锈钢、钴基合金等传统生物医用金属材料,镁合金不仅具有生物可降解特性,而且其弹性模量与人体骨骼很接近,不容易产生“应力屏蔽”,被誉为“新一代先进生物材料”。但镁合金在人体降解速率过快,由此产生的力学失稳和过量降解产物在体内的代谢吸收隐患限制了其在外科植介入医疗领域的大量推广应用。而可生物降解或可吸收的天然和合成高分子(聚合物)是全球量大面广的一类质轻、多功效、生物安全性好的生物医用材料,若将其作为可降解镁合金表面的特种防护涂层并解决好两者表界面之间的生物功能性和力学相容性,将是开发先进镁合金材料及其应用的重要发展方向。本文综述了生物可降解的镁基合金表面天然及合成高分子涂层的最新研究进展,并对其未来的研发及应用发展趋势提出展望。     

Magnesium Powder Metallurgy: Process and Materials Opportunities

The major efforts in magnesium alloy development for automotive applications have concentrated on creep resistant alloys produced by permanent mould and high-pressure die casting routes. While large components, such as crankcases, will never be produced by powder metallurgy, there are smaller components in and around the powertrain which could be fabricated from powder precursors. This article will explore the potential of some of the more recent powder compaction developments, and discuss the alloy development strategies that emerge for magnesium-based components as a consequence of these process developments. In particular, the viability of direct powder extrusion of semi-finished product, using conventional extrusion or equal channel angular processing, combined with T6 heat treatments, will be considered. This article was presented at Materials Science & Technology 2007, Automotive and Ground Vehicles symposium held September 16-20, 2007, in Detroit, MI.     

USAMP Magnesium Powertrain Cast Components: Fundamental research summary

The Magnesium Powertrain Cast Components (MPCC) Project is an effort, jointly sponsored by the U.S. Department of Energy and the U.S. Automotive Materials Partnership (USAMP), to demonstrate the readiness of magnesium for use in powertrain applications by testing a set the magnesium-intensive engines which were designed, cast, and assembled. A second MPCC goal is to promote new and strengthen existing magnesium scientific research in North America. The project investigated several of the newly developed high-temperature (creep-resistant) magnesium alloys, which will potentially experience service conditions in the temperature range of 150–200°C and about 50–110 MPa in stresses (typical powertrain). However, the mechanical and physical behaviors of these new alloys are not fully understood. This article outlines MPCC-supported fundamental scientific research into the workings of these new alloys. The areas of research are: phase equilibrium and computational thermodynamics, creep deformation mechanisms, corrosion, hot tearing, and alloy recycling. Author’s Note: This material is based upon work supported by the Department of Energy National Energy Technology Laboratory under Award Number(s) DE-FC05-95OR22363, DE-FC05-02OR22910, and DE-FC26-02OR22910. This report was prepared as an account of work sponsored by an agency of the United States government. Neither the United States government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States government or any agency thereof.     

阻燃镁合金的研究现状

介绍了镁合金的阻燃机制,综述了阻燃镁合金的研究现状,分析了合金元素Ca,Be,Zn和稀土在阻燃镁合金中的作用,指出了其作为镁合金添加元素的优点和不足之处.阻燃镁合金正向着合金多元化的方向发展,多种合金元素相互匹配,既可达到阻燃的目的,又能不破坏镁合金的性能.阻燃镁合金中添加元素在液面上的化学反应过程及其热力学、动力学机制尚不清楚,需要在此方面进行深入地研究.     

Forming of magnesium alloys at 100 °C by hydrostatic extrusion

Magnesium wrought alloys are of special interest for use as structural parts due to the possibility of obtaining improved and more homogeneous microstructure and mechanical properties compared with cast components. The market for magnesium wrought alloys is still relatively small, and they are only used for special applications due to the high cost of the feedstock. Currently, with the decreasing prices for the primary magnesium extrusion, magnesium has become competitive with aluminum, and is important for upcoming research and development activities. In this study hydrostatic extrusion, as a quite rarely applied technique, was used for deformation of commercial magnesium alloys at 100 °C, which is significantly below the temperature necessary for activation of new gliding systems. All experiments were carried out using typical industrial extrusion parameters like extrusion rate and extrusion ratio but with the objective of obtaining extremely fine-grained materials as are received typically from equal channel angular extrusion processing. These experiments show that the processing of magnesium alloys is possible even at a temperature of 100 °C. The limitations of this processing and the influence of process parameters on the microstructure and mechanical properties of extruded profiles will be discussed.     

镁合金废料的回收

在镁合金零部件生产过程中，特别是在压力铸造生产中，产生出来的废料以及使用后报废的镁合金零件逐渐增多。出于成本和环境因素的考虑，必须对这与日俱增的镁合金废料进行有效回收。本文以生产占90％的镁合金零部件压力铸造为主线，介绍镁合金废料回收的经济分析，镁合金废料的来源和分类、现行回收技术的现状及发展趋势。并介绍香港生产力促进局和重庆硕龙科技公司最近研究开发的一种新型镁合金废料现场精炼回收系统。     

我国搅拌摩擦焊技术的研究现状与热点分析

从搅拌摩擦焊材料、工艺、焊接机理、有限元数值模拟、接头耐腐蚀性等方面分析了国内对搅拌摩擦焊研究取得的成果与现状,并预测了未来几年国内搅拌摩擦焊研究的热点和重点.分析认为:铝合金仍是未来几年搅拌摩擦焊的主要研究材料,而镁合金、铜合金、不锈钢、碳钢以及异种金属的搅拌摩擦焊将也将成为研究的热点.焊接工艺、有限元数值模拟以及接...     

The past,present, and future of DARPA’s investment strategy in smart materials

The Defense Advanced Research Projects Agency (DARPA) smart materials research programs past, present, and future are reviewed in this article. Several articles have been written about the history of smart materials at DARPA;^1–4 therefore, discussions of past efforts are limited and present and future work is emphasized. More importantly, this article presents the authors’ vision of what is next in the smart materials arena, for it is their belief that the journey to truly smart materials and structures has really just begun. For more information, contact Steven Wax, DARPA, Defense Sciences Office, Arlington, Virginia; swax@Darpa.mil.     

铝、镁、钛基材料微弧氧化涂层摩擦学性能研究进展

铝、镁、钛基材料作为最有代表性的阀金属具有比强度高、加工性能好、生物相容性优异等诸多特点,被广泛应用于航空航天、汽车、电子通信、医疗等各大行业。但铝、镁、钛基材料摩擦学性能普遍较差。本文综述了利用微弧氧化技术改善铝、镁、钛基材料摩擦学性能的理论基础和应用研究现状;总结了电解液体系、电参数和反应时间对微弧氧化涂层的表面形貌、成分、组织结构和摩擦磨损性能的影响;重点介绍了微弧氧化直接复合技术和二次复合技术;并对未来的应用和发展进行了展望。     

Modern magnesium-base deformable alloys and composite materials (a review)

State-of-the-art deformable magnesium alloys and magnesium-base composite materials are analyzed. The significance of these materials in advanced fields of engineering is confirmed. It is shown that the main physical and mechanical characteristics of magnesium deformable alloys make them competitive to aluminum alloys used for the same purposes. Prospects of alloys of the Mg-Zn-Zr-REM system are considered. Some efficient processes of production of magnesium-base semiproducts, such as casting with elevated rates of crystallization, hydropressing, superplastic deformation, and direct (ingotless) rolling, are described. It is predicted that the direction of metals science dealing with improvement of traditional and development of novel magnesium alloys will be advanced and the range of their application will widen due to creation of new processes of production of deformable semiproducts from them.     

海洋大气环境下镁合金腐蚀行为研究进展

本文综合研究了海洋大气环境下镁合金腐蚀行为的研究进展,比较分析了各种因素对腐蚀行为的影响,对当前研究进展进行总结并对未来研究方向进行展望。在海洋大气环境下,表面薄电解质溶液膜的包覆是镁合金发生电化学腐蚀的主要原因,且多发生局部腐蚀。相比于内陆大气环境,海洋大气中含有较多无机盐气溶胶颗粒,导致点蚀成为主要的局部腐蚀形式。相对湿度的升高会导致薄电解质膜厚度增加,进而加速整体腐蚀速率。随气温上升,镁合金的大气腐蚀速率线性增加,而空气中的CO₂可以抑制NaCl对镁合金的侵蚀。该领域未来需更多关注具体使役环境下合金的腐蚀机理,以及各种环境因素对腐蚀行为的协同作用机制,以指导海洋用镁合金材料的设计和制备。     

阻燃镁合金材料的研究现状及发展趋势

综述阻燃镁合金材料的研究现状,分析合金元素Ca、Be、Ce、Bi的作用,对阻燃镁合金的一些新发展情况作了介绍.     

QNDE的核心科学与工程基础进展(英文)

对材料和结构缺陷的无损检测(NDT)已经历了50多年的进化演变。在美国,它已经从一个要求零缺陷的检测策略(NDT),向基于损伤可容度设计的检测和评估技术(NDE)过渡。这里是假设部件始终包含一个缺陷,只有那些比断裂力学确定的临界尺寸更大时,需要通过检查将其消除,以重新确定产品的服务周期。介绍了这些因素对于推动模式转变及转换至定量无损检测方面起到的至关重要的作用。一系列的重大研究项目被启动,用于更新无损检测以满足新的要求。重点介绍了在第一项目发展中的研究重点,以及用于定量缺陷定义的DARPA/AFML跨学科项目。它有三个目的:发展新的核心科学/人员基础,使检测技术满足新的要求,确立发展新的领域,即适当的工程设备的阶段,并继续开展定量无损检测(QNDE)系列会议。从这个和其他方案的进展已导致对所涉及的任何检查和技术的各项测量的基本模型的链接为基础的定量无损评价(QNDE)的科学核心。除了讨论这些模式和它们的联系,还将定义核心结构。利用这些模型,一种新的强大的工程工具集已经开发,包括UT,RT和EC技术的模拟程序。这些工具的应用将成为亮点,在包括结构健康监测和状态检修的工作中将令人注目。最后,讨论了QNDE未来机会、远景和方向。     

变形镁合金的研究、开发及应用

综述了国内外主要的变形镁合金材料的基本特性、力学性能和应用领域，介绍了目前变形镁合金材料的研究现状和进展，以及制备高性能变形镁合金材料的新工艺，探讨了镁合金的合金化原理和主要合金元素在变形镁合金中的作用，重点阐述了稀土元素对变形镁合金控能的影响及稀土镁合金的研究与进展。塑性变形与热处理工艺相结合，可获得高强度和优良延展性、更多样化性能的镁合金结构材料。变形镁合金将成为21世纪重要的商用轻质结构材料。     

Comparison of corrosion behaviors of AZ31, AZ91, AM60 and ZK60 magnesium alloys

The corrosion behaviours of four kinds of rolled magnesium alloys of AZ31, AZ91, AM60 and ZK60 were studied in 1 mol/L sodium chloride solution. The results of EIS and potentiodynamic polarization show that the corrosion resistance of the four materials is ranked as ZK60＞AM60＞AZ31＞AZ91. The corrosion processes of the four magnesium alloys were also analyzed by SEM and energy dispersive spectroscopy(EDS). The results show that the corrosion patterns of the four alloys are localized corrosion and the galvanic couples formed by the second phase particles and the matrix are the main source of the localized corrosion of magnesium alloys. The corrosion resistance of the different magnesium alloys has direct relationship with the concentration of alloying elements and microstructure of magnesium alloys. The ratio of the β phase in AZ91 is higher than that in AZ31 and the β phase can form micro-galvanic cell with the alloy matrix, as a result, the corrosion resistance of AZ31 will be higher than AZ91. The manganese element in AM60 magnesium alloy can form the second phase particle of AlMnFe, which can reduce the Fe content in magnesium alloy matrix, purifying the microstructure of alloy, as a result, the corrosion resistance of AM60 is improved. However, due to the more noble galvanic couples of AlMnFe and matrix, the microscopic corrosion morphology of AM60 is more localized. The zirconium element in ZK60 magnesium alloy can refine grain, form stable compounds with Fe and Si, and purify the composition of alloy, which results in the good corrosion resistance of ZK60 magnesium alloy.     

Engineering Research Needs, 1965–1985

This study by the Engineering Research Committee of the Engineers Joint Council examines the future responsibilities of the engineering profession for the creative application of science and technology to meet the changing needs and wants of our society. It appraises a number of engineering research opportunities for which existing institutions and programs appear inadequate.     

镁及镁合金缓蚀剂研究现状与展望

缓蚀剂技术是一种简单有效抑制金属在腐蚀介质中遭到破坏的腐蚀防护手段,在钢铁、铜等传统金属上已有大量研究及应用。由于镁具有接受电子和给予电子能力都比较低的原子结构特点和高活泼的化学性质,对传统金属材料有效的缓蚀剂对镁合金作用并不理想,所以对镁合金的缓蚀剂研究较少、起步较晚。近年来,经过国内外研究机构的不懈努力,对镁合金缓蚀剂的开发和缓蚀机理的研究取得了一定突破,初步建立了镁合金缓蚀剂的评价体系。针对镁合金缓蚀剂的不同应用介质,结合镁合金缓蚀剂的化合物性质,阐述了镁合金缓蚀剂的构效关系、影响缓蚀效率的主要因素、复配缓蚀剂配方优化等最新研究动态,并介绍了其缓蚀机理或协同缓蚀机理。最后,结合镁合金缓蚀剂的研究现状以及新的研究方法及其检测技术的发展,对镁合金缓蚀剂未来的研究方向、发展趋势和应用领域的拓展提出了展望。