离心熔模精铸TiAl合金与ZrO2型壳的界面反应

选用CaO增强的ZrO2作为TiAl熔模精密铸造用陶瓷型壳的面层材料,通过OM、SEM、EDS和XRD对TiAl合金界面反应处进行形貌分析和元素线扫描分析,研究离心熔模铸造TiAl合金与ZrO2型壳的界面反应.结果表明:在较低的转速(200 r/min)条件下,ZrO2陶瓷与TiAl合金的反应层厚度较小,大约为5 μm;而在较高的转速(400 r/min)情况下,ZrO2陶瓷与TiAl合金的反应层厚度约为20 μm,界面有轻微粘砂.     

γ-TiAl与氧化锆陶瓷模壳的界面反应

采用扫描电镜、电子探针、微区分析、面分布等方法研究了CaO稳定的ZrO2陶瓷型壳与TiAl基合金熔体的界面反应.反应层厚度在80-280μm之间,该区域晶界粗大,电子探针面分析证明是明显的富Zr区.延长金属TiAl与模壳的反应时间,以获得较大的反应界面,进一步研究TiAl熔融液与模壳之间的反应机理.     

Ti-47Al-2Cr-2Nb-xTiB_2合金与Al_2O_3陶瓷型壳界面反应的研究

实验室条件下制备了Ti-47Al-2Cr-2Nb-xTiB2(x=0、0.6%、1.0%,体积分数)合金熔体与Al2O3陶瓷型壳的界面反应层。借助SEM、EDS、XRD以及显微硬度测量等手段,对3种TiAl基合金熔体与Al2O3陶瓷型壳的界面反应情况进行了分析和比较。结果表明,TiAl基合金中加入TiB2,能有效减少TiAl基合金熔体与Al2O3陶瓷型壳的界面反应。TiAl基合金与AlO陶瓷型壳间的界面反应是一种不均衡进行的扩散型化学反应,并建立了界面反应的宏观模型。     

EDXRF法直接测定氧化物陶瓷材料组分

叙述了用能量色散X射线荧光法(EDXRF)同时测定氧化物陶瓷材料组分的分析方法。该方法对样品无损，可直接测定ZrO2 Y2O3，ZrO2 CaO，ZrO2 Y2O3 CaO 3种陶瓷材料中的CaO，Y2O3和ZrO2；该方法快速、简便、可适用于粉末混合料和经高温烧结后的上述3种陶瓷材料；测定各组分的含量范围为：2％-25％的CaO，1．5％-20％的Y2O3，70％-98％的ZrO2，测定CaO和Y2O3的相对标准偏差好于2％，测定ZrO2的相对标准偏差好于1％。     

熔模铸造Ti-1100高温钛合金的界面反应(英文)

研究不同面层材料的Ti-1100高温钛合金界面反应特性。通过对比反应层的厚度,元素分布以及微观硬度研究了面层型壳材料以及型壳预热温度对界面反应的影响。结果表明:采用ZrO2面层材料型壳浇注的Ti-1100铸件反应层的厚度和硬度明显高于采用Y2O3面层材料型壳浇注的合金;型壳预热温度越高,界面反应越剧烈;在相同的型壳面层材料和型壳预热温度条件下,Ti6Al4V合金铸件的界面反应α层比Ti-1100合金铸件界面反应层薄,显微硬度低,表现出较好的稳定性。     

BN基复合型壳熔模精铸钛镍合金时的界面反应

研究了一种新型钛合金精密铸造用型壳--BN基复合型壳在精铸钛镍合金时的界面反应及反应层的形成机制.研究表明,即使在钛镍合金熔液过热较高(浇注温度为1 600℃)的情况下,这种型壳与钛镍合金的反应也较小,铸件表面反应层厚度仅为几个μm.BN基复合型壳,在浇注温度较低的情况下,有望成为Y2O3、ZrO2或钨粉等钛合金熔模精密型壳面层材料的替代品.     

高铌TiAl合金与陶瓷型壳的界面反应

研究了高铌TiAl合金Ti-44Al-8Nb-0.2W-0.1B-0.1Y(at%)分别与Al2O3/ZrO2/Y2O3坩埚的界面反应。测得界面反应层的厚度分别为40,170和20μm。研究中最大的发现在于Ti-44Al-8Nb-0.2W-0.1B-0.1Y(at%)合金在3种坩埚中凝固后显微组织的转变。经测定该合金在3种坩埚中凝固获得的试样中氧含量分别为0.35,0.41和0.11(at%)。由于在合金熔化和凝固过程中,坩埚中的氧元素扩散进入合金基体,较高的氧含量导致合金显微组织发生转变,在与Al2O3和ZrO2坩埚反应的合金中发生了包晶反应。作为对比,选取一种低铌含量的TiAl合金Ti-49.5Al-2Cr-2Nb。经测定在3种坩埚中反应的氧含量分别为0.40,0.63和0.25(at%),但是组织却没有明显的差异。     

Structure Heredity Effect of Mg-10Y Master Alloy in AZ31 Magnesium Alloy

研究了高铌TiAl合金Ti-44Al-8Nb-0.2W-0.1B-0.1Y (at％)分别与Al2O3/ZrO2/Y2O3坩埚的界面反应.测得界面反应层的厚度分别为40,170和20 μm.研究中最大的发现在于Ti-44Al-8Nb-0.2W-0.1B-0.1Y(at％)合金在3种坩埚中凝固后显微组织的转变.经测定该合金在3种坩埚中凝固获得的试样中氧含量分别为0.35,0.41和0.11 (at％).由于在合金熔化和凝固过程中,坩埚中的氧元素扩散进入合金基体,较高的氧含量导致合金显微组织发生转变,在与Al2O3和ZrO2坩埚反应的合金中发生了包晶反应.作为对比,选取一种低铌含量的TiAl合金Ti-49.5Al-2Cr-2Nb.经测定在3种坩埚中反应的氧含量分别为0.40,0.63和0.25 (at％),但是组织却没有明显的差异.     

Ti/ZrO2和TiAl/ZrO2反应的差热分析

借助SEM和差热分析研究Ti-ZrO2（CaO）和TiAl-ZrO2（CaO）体系在不同加热速率时的界面显微组织和反应温度,并利用Kissinger方程对反应动力学参数进行计算。结果表明：随着加热速率的提高,Ti-ZrO2（CaO）和T认1．ZrO2（CaO）体系的化学反应逐渐减弱,初始反应温度逐渐升高;Al元素的加入使Ti和ZrO22（CaO）的初始反应温度提高近170℃,从而弱化Ti与ZrO2（CaO）的界面反应;Ti-ZrO2（CaO）体系和TiAl-ZrO2（CaO）体系反应活化能分别为l348kJ／mol和l675kJ／mol,反应级数分别为1．51和1．59。     

钛铝基合金与4种陶瓷界面反应的研究

借助SEM和差热分析(DTA),研究了Ti48Al2Cr2Nb合金与Y2O3、ZrO2(Y2O3稳定)、ZrO2(MgO稳定)和锆英砂4种陶瓷耐火材料界面反应后金属侧的显微组织,并测定了Ti48Al2Cr2Nb合金与Y2O3、ZrO2(Y2O3稳定)、ZrO2(MgO稳定)和锆英砂4种陶瓷耐火材料的初始反应温度.结果表明,Ti48Al2Cr2Nb合金与锆英砂反应后的显微组织最粗大,为菊花状,而与Y2O3反应产物最细小均匀,为颗粒状;4种陶瓷材料对Ti48Al2Cr2Nb合金的初始反应温度依次为:1500,1400,1380和820℃.     

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.