烧结技术有望用于超细WC／Co

在欧洲ＰＭ９９会议上，专家们探讨了细的和超细碳化物的烧结工艺研制和硬质合金性能的研究． Ｇ．Ｇａｓｔｒｉｃｈ博士介绍了Ｆｒａｕｎｈｏｆｅｒ和Ｓｔａｒｃｈ公司联合研究的硬质合金的烧结模型，发现收缩和液相生成有强烈联系，目前生产规模从１００ｍｇ到１０００ｋｇ．Ｄ．Ａｇｒａｗａｌ教授介绍了采用微波烧结技术控制超细ＷＣ／Ｃｏ复合压坯的晶粒长大的研究进展．微波烧结技术是很有希望的技术，因为微波的快速加热可使烧结体的晶粒长大减小到最低程度．传统的加热烧结方法，热量是从烧结体外表面传送到内部，而微波加热烧结方…     

共沉淀回收硬质合金的组织结构和性能

以共沉淀回收废硬质合金的Ｗ－Ｃｏ复合物为原料制备的再生ＷＣ－１０Ｃｏ硬质合金具有ＷＣ平均晶粒细、矫顽磁力和硬度高的优点，但较多的ＷＣ晶粒缺陷、较高的ＷＣ晶粒邻接度Ｃｗｃ－ｗｃ和不连续长大的粗晶ＷＣ的存在降低了其强韧性。用共沉淀回收料制备两相ＷＣ－Ｃｏ合金，须实施较生产普通ＷＣ－Ｃｏ合金更为严格的碳含量控制。     

细晶粒WC—VC—Co硬质合金

本论文描述了１０ｗｔ％ＶＣ的ＷＣ－ＶＣ－Ｃｏ硬质合金的生产过程和部分性能，该合金的可烧结性表明比预期的要好，而且硬度比同等钴含量的ＷＣ－Ｃｏ硬质合金要高，韧性优于相同硬度的ＷＣ－Ｃｏ硬质合金。     

超细晶粒WC—Co硬质合金的剪切模压成型工艺

采用剪切模压新工艺成型,通过真空烧结制备出了超细晶粒ＷＣ－Ｃｏ硬质合金。研究了不同成型剂的特性、成型剂的配比、加入量以及压制力对剪切模压成型的影响。研究结果表明,采用剪切模压成型工艺可获得很高的成型质量,从而制备出具有较好物理力学性能的超细ＷＣ－Ｃｏ硬质合金。     

WC—8（Fe／Ni／Co）R硬质合金的研究

用Ｆｅ、Ｎｉ部分取代ＷＣ－８Ｃｏ合金（牌号ＹＧ８）中的粘结剂Ｃｏ,再添加微量稀土Ｒ制得ＷＣ－８（Ｆｅ／Ｎｉ／Ｃｏ）Ｒ硬质合金,测试了其物理机械性能,研究了粘结剂各种成份比例及烧结温度对硬质合金的影响。结果表明：ＷＣ－８（Ｆｅ／Ｎｉ／Ｃｏ）Ｒ硬质合金的性能可以达到ＹＧ８的性能标准。利用扫描电镜（ＳＥＭ）及Ｘ射线衍射（ＸＲＤ）对其作了显微结构分析,同时探讨了影响ＷＣ－８（Ｆｅ／Ｎｉ／Ｃｏ）Ｒ合金性能的     

提高WC—Co硬质合金顶锤质量的研究

对烧结后的硬质合金顶锤进行热等静压（ＨＩＰ），能有效提高其密度，使其在合成金刚石生产中使用寿命普遍延长３—４倍。热等静压的最佳工艺条件是：温度在１３５０～１３７５℃，压力为８０～１００ＭＰａ，保温保压时间１００～１２０ｍｉｎ。同时，较全面地观察和分析了ＷＣ—Ｃｏ硬质合金破裂的行为，并阐述了采用ＨＩＰ处理能提高ＷＣ—Ｃｏ硬质合金顶锤质量的原因。     

纳米结构碳化钨／钴粉末的开发和应用

改善机械性能的潜在利益继续推动着超细显微结构硬质合金材料的研究。目前尚在开发阶段的烧结新技术正开始利用纳米结构ＷＣ－Ｃｏ粉末的优势，有望将烧结颗粒的平均粒度减小到１００ｎｍ以内。完全纳米结构的ＷＣ－Ｃｏ硬质合金还有待努力，但是第一步已就位，即纳米结构粉末的生产。这种粉末的商业化生产运用了喷射转变工艺，制得的粉末由弥散于金属粘结相的２０￣５０ｎｍ，ＷＣ颗粒组成。这些小ＷＣ颗粒比应用传统碳化工艺制得的     

Fe-W-Co和Fe-W-Co-Ni合金的时效硬化

对ＦｅＷＣｏ和ＦｅＷＣｏＮｉ合金的时效硬化特性进行了研究。结果表明两种合金均具有强的时效硬化能力。ＦｅＷＣｏＮｉ低温硬化速率较ＦｅＷＣｏ高。随着时效温度升高，ＦｅＷＣｏ硬化速率迅速上升。ＦｅＷＣｏ合金６３０℃时效１０ｍｉｎ，硬度从淬火态的４７ＨＲＣ上升到６４ＨＲＣ。淬火组织为具有高位错密度的板条马氏体。时效初期出现调幅结构，产生较大共格应力。５７０℃×２ｈ时效，ＦｅＷＣｏ的析出物比ＦｅＷＣｏＮｉ更为弥散细小。这是ＦｅＷＣｏ合金较ＦｅＷＣｏＮｉ合金有较强时效硬化能力的原因。     

电溶解法回收废残WC－Co硬质合金

报导了用电溶解法回收废残ＷＣ－Ｃｏ硬质合金的工艺和实践，分析了电溶解ＷＣ－Ｃｏ硬质合金时反应过程的机理，指出：只要适当控制电解条件，就可以将ＷＣ－Ｃｏ合金进行分离和再生。     

电溶解法回收废残WC—Co硬质合金

报导了用电溶解法回收废残ＷＣ－Ｃｏ硬质合金的工艺和实践，分析了电溶解ＷＣ－Ｃｏ硬质合金时反应过程的机理，指出：只要适当控制电解条件，就可以将ＷＣ－Ｃｏ合金进行分离和再生。     

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.     

Effects of Post-weld Heat Treatment on Microstructure,Mechanical Properties and the Role of Weld Reinforcement in 2219 Aluminum Alloy TIG-Welded Joints

In as-welded state, each region of 2219 aluminum alloy TIG-welded joint shows diff erent microstructure and microhardness due to the diff erent welding heat cycles and the resulting evolution of second phases. After the post-weld heat treatment, both the amount and the size of the eutectic structure or θ phases decreased. Correspondingly, both the Cu content in α-Al matrix and the microhardness increased to a similar level in each region of the joint, and the tensile strength of the entire joint was greatly improved. Post-weld heat treatment played the role of solid solution strengthening and aging strengthening. After the post-weld heat treatment, the weld performance became similar to other regions, but weld reinforcements lost their reinforcing eff ect on the weld and their existence was more of an adverse eff ect. The joint without weld reinforcements after the post-weld heat treatment had the optimal tensile properties, and the specimens randomly crack in the weld zone.     

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.     

The First Phase of the SRIF Industrialized Base in ＂West Area＂ Has Been Put into Operation

After nearly two years＇ tense construction, the first phase of industrialized base of Shenyang Research Institute of Foundry （SRIF）, located at the Tiexi Casting and Forging Industrial Park in the west of Tiexi District, has now been completed and formally put into operation.