低蒸气压中温钎料研究进展

熔点在400～600℃的低蒸气压中温钎料在电子器件、电真空元件、硬质合金刀具等钎接领域的应用十分广泛.本文概述了中温钎料的最新研究现状,指出在Ag-Cu二元舍金中复合添加适量的Sn、In、Ni、Si、Ge和Ga元素进行合金化处理,是获得低蒸气压中温真空钎料的有效途径.     

Ag基中温钎料及焊膏的研究进展

Ag基钎料具有良好的润湿性、耐腐蚀性、导电性、导热性和高强度等特点,使其成为应用广泛的钎焊材料。通常以银基钎料为基础添加合金或稀土元素来改善其性能,同时对钎料的制备工艺进行创新。随着焊料的发展,焊膏这种新型焊接材料取代传统钎料。综述了Ag基为主中温钎料的研究现状以及中温银基焊膏的研究进展,展望了银基中温钎料的发展方向。     

电子工业用金基和银基中温钎料的研究进展

由于金基和银基合金钎料蒸气压低,润湿性好,焊接接头强度高,耐腐蚀性优良等特点,使它们成为电子工业中的主要钎焊材料.而熔化温度在400～600℃的电子封装用金基和银基钎料仍是研究的热点.这些钎料都普遍存在加工性不好等问题,给钎料的生产和应用带来了一定的局限性.本文概述了目前应用在电子工业中的金基和银基合金中温钎料的研究进展,同时也从钎料的钎焊特性和加工性能等方面展开了讨论.     

电子封装用低银含量无铅钎料的研究和应用进展

电子封装用钎科从传统锡铅合金向无铅钎料的转换过程中适逢手持便携式电子器件高速增长期,加之近年来金属价格的持续上涨,因而低银含量无铅钎料合金作为第二代无铅钎料成为关注的焦点.本文阐述了无铅低银钎料的研究与发展现状,同时分析了其应用情况,最后,对谊钎科及其可靠性的发展趋势进行了分析和展望.     

钴对Ag—Cu—Pd合金钎料性能的影响

研究结果表明,在Ａｇ－Ｃｕ－Ｐｄ合金钎料中添加０．２－１．０ｗｔ％Ｃｏ后,对钎料的物理性能,电学性能以及力学性能无明显影响,但对ＢＡｇ６５ＣｕＰｄ钎料在某些母材上过度的铺展性确有显著地抑制作用,Ａｇ６５Ｃｕ２０Ｐｄ１５－ｘＣｏｘ钎料可以部分地取代电子器件中的金基纤料。     

中温无镉钎料的研究进展

本文论述了国内外在"无镉化"的趋势下中温无Cd钎料研究的现状,主要通过在Ag钎料中添加合金元素,如Ga,In,Sn,Ni等来调整钎料合金熔化温度区间及提高钎料的性能,但与含Cd钎料相比,在熔化温度及钎料合金的工艺性能和力学性能方面仍有较大差距.同时在Ag钎料的替代钎料--中温Cu基钎料的研究上也取得了一定的成果,但在钎焊钢及不锈钢方面受到了局限,还不能完全替代Ag基钎料.     

珩磨工具用中温钎焊材料的研制

针对目前珩磨条钎焊存在的问题,采用中温钎焊对珩磨工具进行了连接试验,对中温钎焊用钎料的化学成分进行了调整,测试了钎料的熔化温度、钎料对珩磨条的润湿性以及钎焊接头的抗拉强度,并比较了不同钎料钎焊后珩磨工具的变形量.研究表明:中温钎焊工艺变形小,强度较高,是珩磨条连接的可行方式.     

环保型无镉无银中温钎料Cu-Sn-Sb的制备及性能测试

通过试验确定了无镉无银、价格低廉的中温钎料Cu-Sn-Sb的组成为w(Sn)8%~12%,w(Sb)2%~4%。该新型钎料的润湿性能和综合力学性能明显优于传统的B-Ag20CuZn和B-Ag25CuZn等中温钎料。显微结构研究表明,SnSb金属件化合物的出现,促使钎料微观形貌转化为胞状,从而有利于改善钎料的延展性和机械加工性能。     

采用复合钎料的铝合金中温真空钎焊技术

为解决铝合金中温钎焊时难以制备出实用的钎料问题,设计制备了厚度0.1～0.2 mm的Al-Si-Cu复合钎料箔带,钎料呈三明治状叠层结构,具有与普通Al-Si钎料同样的塑性,液相线温度541℃.该复合钎料可方便地用于铝合金实际结构的中温真空钎焊.工艺及性能试验结果表明,钎料具有良好的钎焊工艺性,钎焊2A50接头平均剪切强度172 MPa,并成功用于2A50叶轮结构的真空钎焊.     

中温铝钎料的研究现状及发展趋势

介绍了目前国内外中温铝钎焊研究较多的几类钎料合金,包括Al-Si系、Sn-Zn系、Sn-Pb系、Cd-Zn系、Pb-Bi系、Zn-Al系等的研究现状,并进行了综合对比分析,认为Zn-A1系合金作为中温铝钎料将具有美好的应用前景.     

Three-Dimensional Growth of Coherent Ferrite in Austenite: A Molecular Dynamics Study

Coherent second phase often exhibits anisotropic morphology with specifi c orientations with respect to both the second and the matrix phases. As a key feature of microstructure, the morphology of the coherent particles is essential for understanding the second-phase strengthening eff ect in various industrial alloys. This letter reports anisotropic growth of coherent ferrite from austenite matrix in pure iron based on molecular dynamics simulation. We found that the ferrite grain tends to grow into an elongated plate-like shape, independent of its initial confi guration. The fi nal shape of the ferrite is closely related to the misfi t between the two phases, with the longest direction and the broad facet of the plate being, respectively, consistent with the best matching direction and the best matching plane calculated via the Burgers vector content(BVC) method. The strain energy calculation in the framework of Eshelby's inclusion theory verifi es that the simulated orientation of the coherent ferrite is energetically favorable. It is anticipated that the BVC method will be applicable in analysis of anisotropic growth and morphology of coherent second phase in other phase transformation systems.     

Effect of Short-Time Aging on the Pitting Corrosion Behavior of a Novel Lean Duplex Stainless Steel 2002

The effect of short-time aging in the temperature range between 400 and 1000 °C on the pitting corrosion behavior and mechanical property of a novel lean duplex stainless steel(LDSS) 2002 was investigated through the potentiostatic critical pitting temperature(CPT) tests and the Charpy impact tests. Both the pitting corrosion resistance and the toughness of aged specimens degraded due to the precipitation of detrimental secondary phases and the most significant reduction of CPT and impact energy emerged at 650 °C concurrently. The CPT of LDSS 2002 specimen aged at 650 °C decreased by 28 °C, and the impact energy dropped from 69 to 29 J/cm~2 compared with the solution-annealed sample. Transmission electron microscopy characterization showed that the main precipitates in LDSS 2002 were Cr_2N and M_(23)C_6 along the ferrite–austenite grain boundaries.     

INTRODUCTION TO PATENTS

The invention provides a method of making a mold which can reduce SOx generation rate while preventing decrease in hardening rate in the case of using sulfuric acid for a hardener composition. The method has a mixture step in which fire-resistant particles, a hardener composition and a binder composition are mixed to obtain a composition for a mold. The hardener composition contains sulfuric acid. In the mixture step, sodium carbonate is added. A molar ratio of the sulfuric acid to the sodium carbonate is 0.5 or more and 4.0 or less.     

China Foundry Week 2014

China Foundry Week, hosted by the Foundry Institution of Chinese Mechanical Engineering Society （FICMES） each year, is a large academic event in China. It is one of the ten high-impact activities sponsored by the Chinese Mechanical Engineering Society.     

17th Conference of Hydrodynamic and Electromechanical Control Engineering Call for papers

正1.Contents In order to promote the academic exchanges and technical communication of the research in the field of fluid power transmission and control,fluid control engineering specialized committee of the Chinese Society of Theoretical and Applied Mechanics will hold the 17th Conference of Hydrodynamic and Electromechanical Control Engineering on July 27-29,2014 in Tibet,Lhasa city.     

Information for Contributors

正The Transactions of Nonferrous Metals Society of China,founded in 1991 and sponsored by The Nonferrous Metals Society of China,is published monthly now and mainly contains reports of original research which reflect the new progresses in the field of nonferrous metals science and technology,including mineral processing,extraction metallurgy,metallic materials and heat treatments,metal working,physical metallurgy,powder metallurgy,with the emphasis     

Preface

<正>We are pleased to present this Special Issue of Transactions of Nonferrous Metals Society of China containing selected papers from the First Asian Conference on Aluminum Alloys(ACAA-2013),held in Beijing,China,13–17 October 2013.This conference has been initiated,with approval of     

Information for Contributors

The Transactions of Nonferrous Metals Society of China, founded in 1991 and sponsored by The Nonferrous Metals Society of China, is published monthly now and mainly contains reports of original research which reflect the new progresses in the field of nonferrous metals science and technology, including mineral processing, extraction metallurgy, metallic materials and heat treatments, metal working, physical metallurgy, powder metallurgy, with the emphasis on fundamental science. It is the unique preeminent publication in English for scientists, engineers, under/post-graduates on the field of nonferrous metals industry. This journal is covered by many famous abstract/index systems and databases such as SCI Expanded, Ei Compendex Plus, 1NSPEC, CA, METADEX, AJ and JICST.     

FORMULAS OF TENSION OF CONTINUOUS ROLLING PROCESS

The development of computer controlled continuous rolling process calls for a mathematical expression that can express the inequality condition of "constant flow". Tension is the link of the continuous rolling process. From the condition of dynamic equilibrium, a differential equation of tension is given out. On the basis of the physical rules established from the industrial practice and experimental studies, the law of volume constancy, the linear relation of forward slip and tension, the state equation of continuous rolling, the formula of dynamic tension, and the formula of static tension have been obtained. These formulae reflect the functional relations between tensions, thickness, roll velocity, and time in the continuous rolling process. It is implied that the continuous rolling process is a gradually steady, controllable, and measurable dynamic system. An assumption of predicting the thickness of a steel plate using these tension formulae is also put forward.     

Bulletin of the Awards in 2013

<正>Five reviewers and 9 published articles are selected as the Excellent Rewewerand Excellent Article in 2013 respectively.Excellent Reviewers:Prof.Z ongyi Ma(Institute of Metal Research,CAS,C hina);Prof.Y ongbo Xu(Institute of Metal Research,CAS,C hina);Prof.Guangping Zhang(Institute of Metal Research,C AS,C hina);Prof.Z hendui Cui(Tianjin University,China);