交变磁场对SHS陶瓷复合钢管陶瓷层结构和性能的影响

将交变磁场引入自蔓延反应,研究其对复合管陶瓷层结构和性能的影响.结果表明:交变磁场可以促进燃烧反应的进行,但并不改变陶瓷层的相结构.随着磁感应强度的增加,α-Al2O3的枝晶尺寸减小,形态逐渐向细小的晶形过渡.引入交变磁场后,复合管的抗压溃强度和抗剪强度均有提高.其中当磁感应强度为0.20 T时,抗压溃强度和抗剪强度达到418和19.5 MPa,比未引入交变磁场前分别提高了19.1%和21.9%.     

自蔓延-离心法制备金属间化合物/陶瓷内衬复合钢管的实验研究

采用自蔓延－离心工艺制备出Fe2Ti金属间化合物／Al2O3陶瓷内衬复合钢管。应用扫描电镜、能谱分析仪以及X射线衍射分析方法对内衬的显微组织及物相构成进行了分析。结果表明，内衬主要由大小不均的颗粒状或团聚状金属间化合物Fe2Ti、规则块状Al2O3陶瓷以及一定数量的自蔓延反应不完全产物Ti3O5构成。衬层内壁有一以Al2O3、FeO.Al2O3为主的陶瓷薄层。与SHS－离心复合管陶瓷内衬相比，Fe2Ti/Al2O3内衬在保持较高硬度的同时具备了一定的韧性。     

SHS-离心法制备Fe2Ti/Al2O3内衬复合钢管

采用SHS-离心法制备出金属间化合物/陶瓷内衬复合钢管.利用扫描电镜、能谱仪以及X射线衍射分析方法对内衬组织结构进行了分析.试验结果表明,内衬主要由大小不均的颗粒状或团聚状金属间化合物Fe2Ti、规则块状Al2O3陶瓷以及一定数量的自蔓延反应不完全产物Ti3O5构成.衬层内壁有一以Al2O3,FeO@Al2O3为主的陶瓷薄层.与常规SHS-离心法制得的复合管陶瓷内衬相比,Fe2Ti/Al2O3内衬在保持较高硬度的同时具有一定的韧性.     

添加Al2O3对重力分离-SHS法制备Al2O3/Fe复合管组织的影响

采用自蔓延高温合成(Self-propagating High-temperature Synthesis,SHS)重力分离法制备了Al2O3/Fe陶瓷内衬复合管.采用XRD、SEM方法分析了添加剂Al2O3对复合陶瓷相组成、陶瓷层的表面质量以及对Al2O3/Fe过渡层的影响.XRD分析表明,陶瓷层主晶相为α-Al2O3、FeO·Al2O3,加入Al2O3添加剂后,不会改变相组成;SEM分析表明,添加剂Al2O3的加入会降低过渡层的质量,使过渡层变薄,结合形式由冶金结合变为机械结合.     

纳米铝热体系制备陶瓷复合钢管组织及性能

采用纳米铝热体系制备了陶瓷复合钢管,研究了纳米铝热剂中添加4%Na2B4O7+2%、4%、6%、8%(质量分数)纳米SiO2对其组织性能的影响。XRD分析结果表明,陶瓷层主相为α-Al2O3和FeAl2O4,杂相为Al2SiO5和B2O3;金相显微镜和SEM观察表明,α-Al2O3枝晶较细,排布密集,FeAl2O4呈晶间分布;测试结果表明陶瓷致密度可达95%,压溃强度和压剪强度分别可达499 MPa、22.6 MPa。     

重力SHS制备陶瓷内衬复合管中稀释剂使用原则的探讨

采用重力分离-自蔓延高温合成法制备了Al2O3／Fe陶瓷内衬复合管。研究了两种稀释剂SiO2、CaF2对陶瓷层质量的影响。试验结果表明，SiO2对陶瓷层的影响远大于CaF2，SiO2加入量过多可引起复合管底端陶瓷层孔隙度的明显增大。单独添加SiO2适宜的加入量不超过2％，CaF2的添加量为2％～8％。混合添加可以取得更好的效果，但SiO2的加入量不应超过CaF2的加入量，当添加4%SiO2和4％CaF2时，陶瓷层的密度可以达到3．910g·cm^-3。     

SHS复合管接合界面结构及性能研究

采用Al-Fe2O3-GrO3-Ti燃烧体系，制备出含有FeTi，FeCr，FeAI金属间化合物的金属过渡层与陶瓷层双层复合结构的复合管。研究发现：利用金属间化合物作为梯度过渡层，使得基体与内衬层形成牢固的冶金结合，提高了结合强度；同时，高硬度的金属过渡层与陶瓷层组成的双层复合结构使复合管的使用寿命和安全稳定性显著提高。     

添加剂对离心SHS陶瓷复合钢管组织结构和性能的影响

针对Al Fe2 O3 体系 ,研究了ZrSiO4 和TiO2 添加剂对离心SHS陶瓷复合钢管组织结构和性能的影响。添加ZrSiO4 时 ,没有致密化作用 ,陶瓷层主要由α Al2 O3 ,FeAl2 O4 和很少量的m ZrO2 等相构成 ,其结合强度随着ZrSiO4 量的增加而下降 ,而后又有一定程度的提高 ,分解出的ZrO2 对陶瓷基体有微裂纹韧化作用。当添加TiO2 时 ,致密化作用好 ,在TiO2 添加量为 10 %时 ,陶瓷层的孔隙率下降了 42 %。陶瓷层主要由α Al2 O3 ,FeAl2 O4和极少量的Fe4 (TiO4 ) 3 等相构成 ,其结合强度随着TiO2 量的增多有较大幅度提高。TiO2 促进烧结 ,提高了Al2 O3的致密度和强度 ,减小了Al2 O3 的热裂倾向。     

重力分离SHS陶瓷内衬复合管陶瓷致密化技术探讨

在Al/Fe2 O3 燃烧体系下 ,通过阐述重力分离SHS技术合成陶瓷内衬复合管所涉及的燃烧合成、液相分离和陶瓷凝固 3个重要的基本过程 ,着重探讨重力分离SHS法制备陶瓷内衬复合管中陶瓷致密化技术 ;试验证明 ,建立合理的复合添加剂体系和优化合成工艺可有效地提高重力分离SHS陶瓷内衬复合管品质。     

Al_2O_3陶瓷与5005铝合金的高频感应钎焊

为实现Al2O3陶瓷与5005铝合金的低温连接,采用Ag-Cu-Ti粉末对Al2O3陶瓷表面进行活性金属化处理.结果表明,当活性金属化温度为880~900℃,保温时间10 min时,在Al2O3陶瓷界面形成连续致密无缺陷的Ti3Cu3O反应层.采用Al-Si钎料对活性金属化Al2O3陶瓷与5005铝合金进行高频感应钎焊,研究了接头的典型界面组织及其形成过程.结果表明,当温度为600℃,保温时间为1 min时,铝合金侧由团状α-Al和晶间渗入的AlAg-Cu共晶组织构成,团状α-Al上有板条状初晶硅出现,Al2O3陶瓷侧有弥散分布的过共晶Al-Si组织,Ti3Cu3O反应层的形成是实现Al2O3陶瓷与5005铝合金可靠连接的关键,接头的最大抗剪强度达到52 MPa.     

新型的治疗阿尔茨海默氏症药物(1-二甲基磷酰基-2,2,2-三氯)-乙基-1-醇烟酸醋对体外神经细胞的作用

目的: 观察本实验室合成的一种治疗阿尔茨海默氏症(AD)的药物(1-二甲基磷酰基-2, 2, 2 -三氯)-乙基^-1-醇烟酸醋(NMF),对体外培养的皮层神经细胞活性的影响以及对海人藻酸(KA)所致的神经损伤的保护作用。方法: 采用体外培养皮层神经元的方法,解剖分离 15 d胚胎小鼠皮层神经细胞, 接种于 96孔板,48 h 后加药并培养 72 h,以 MIT 法 观察 NMF 对小鼠皮层神经细胞活性的影响;同时将接种于 24 孔板的细胞预先给予 NMF,d 3 时加或不加KA处理后,以台盼蓝染色鉴别并计数死、活细胞,可得出细胞的存活率。结果: NMF 明显促进胎鼠皮层神经元活性,其中 NMF1、0. 1、10nmol·L^-1促进神经元活性增殖率分别高达 34.7%、37.4%、36. 7%, NMF 明显促进正常胎鼠皮层神经元存活卒,与对照组比较,10nmol·L^-1 NMF 对皮层神经元的存活率分别提高 39.3%、73.5%。 NMF能显著 对抗 KA 所致的神经元损伤,与 KA 损伤组相比, NMF0.1、10、10nmol·L^-1对损伤皮层神经元的保护率分别为 77.30%、80.10%、84.15%。结论: NMF 明 显促进胎鼠皮层神经元的洁性、提高正常皮层神经元,的存活卒,并能有效地保护KA所致的神经元损伤,提示 NMF 是一种很有潜力的治疗 AD 的药物。     

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.