Be对7475铝合金组织及性能的影响

采用再结晶退火和时效硬化两种热处理方式,研究了Be对7475铝合金组织及性能的影响.结果表明,0.023%的Be能细化7475铝合金晶粒,提高其综合力学性能,并能提高再结晶温度,延长再结晶孕育期,降低再结晶速度,同时还加快了该合金的时效硬化进程.     

7475铝合金扁锭熔铸工艺研究

分析了7475铝合金扁锭裂纹、疏松倾向大的原因.从控制化学成分、调整铸造应力、提高熔体纯净度、加强晶粒细化等方面入手，防止7475铝合金扁锭铸造时发生裂纹、疏松缺陷.     

7475铝合金ECAP变形后的组织和性能

等径弯曲通道变形(简称ECAP)具有获得超细晶组织和改善力学性能的潜力。对7475铝合金在523K和573K下进行了ECAP变形，等效真应变达12左右，ECAP后平均晶粒尺寸约为0．29μm和0．5μm拉伸试验的结果表明：ECAP大大改善了合金的塑性，同时也提高了合金的屈服强度和拉伸强度。     

热轧工艺对AZ61镁合金铸轧板显微组织的影响

通过研究不同温度下AZ61镁合金铸轧板坯的再加工性能,发现铸轧AZ61镁合金板坯在400、350 ℃时极限再加工变形量大于80%,而在300 ℃时减小到60%左右,在250 ℃时其极限再加工压下量下降到40%左右,200 ℃时进一步降低到20%～30%之间,在室温下极限压下量仅为10%左右.而从变形组织来看,在极限变形压下量范围内,冷轧微观组织与原始态的没有本质区别;200 ℃时轧制晶粒明显伸长,呈纤维状;在高于250 ℃轧制时,晶粒明显细化;在400 ℃轧制时,晶粒细化效果显著,晶粒平均尺寸达到5 μm左右.     

高强铝合金7475超塑性材料的性能

最近由于设计简单和要求较高的产品的需要量增加对超塑性成型材料产生很大兴趣。板材在超塑性状态下成型,可以得到完整的部件。由此发现了高温铝合金7475具有超塑性。采用这种合金的试验已得出结果。铝合金7475的板材具有超塑性。在晶粒度为10微米和变形温度为516℃以及应变速率为2×10~(-4)秒~(-1)时,伸长率为780％。变形性能首先受到晶粒度值d、变形温度T和应变速率ε的影响。一般是:e～d~(-n),n=1.8至2.5(560℃)。变形的激活能为84千焦/克     

限制模压变形1060纯铝的组织演化与晶粒细化

设计平行模压变形、180°交叉模压变形、90°交叉模压变形对1060纯铝进行系列限制模压变形(CGP)试验,采用透射电镜研究该材料在不同变形工艺下的组织演化规律和晶粒细化速率.结果表明:变形工艺不影响组织的演化规律,但显著影响晶粒细化速率、晶粒细化效果以及大角度晶界的形成;90°交叉模压变形最优.在相同的变形温度、变形速率和应变累积条件下,所能达到的晶粒细化速率和大角度晶界的数量取决于剪切变形模式.     

变形温度对X52管线钢晶粒细化的影响

为使X52管线钢产品晶粒组织细化,综合性能提高,研究了X52钢变形温度对组织细化及超细晶粒产生的影响.热模拟试验发现,变形可使X52管线钢细化晶粒,并促使超细铁素体品粒在A3温度以上出现,而且变形温度越低,越有利于超细晶组织的形成.     

23Co13Ni11Cr3Mo钢高温变形奥氏体晶粒的演化规律

在Gleeble 1500热模拟机上对23Co13Ni1 1Cr3Mo超高强钢进行了大变形等温压缩实验,研究了变形温度、应变速率对奥氏体晶粒尺寸的影响.结果表明:奥氏体晶粒尺寸对数与变形温度倒数、应变速率对数和Z参数对数呈线性关系,降低温度、提高应变速率、增大Z参数,有利于细化晶粒,改善晶粒组织均匀性.根据实验结果得出了23Co13 Ni1 1Cr3Mo钢锻造温度和应变速率范围,建立了奥氏体晶粒尺寸模型,模型预测值与实验值吻合较好.     

模具结构对反复模压变形5052铝合金显微组织的影响

在自制的新型组合式模具上对商业5052铝合金板材进行两种不同结构模具下的反复模压变形,并用光学显微镜和透射电镜对变形合金进行显微组织分析。结果表明:限制模压(Constrained Groove Pressing,CGP)变形和非限制模压(UnconstrainedGroove Pressing,UGP)变形均能够有效细化5052铝合金,其平均晶粒尺寸随变形道次的增加而减小。在两种不同结构模具的反复模压变形下,5052铝合金呈现出不同的组织特征。经CGP变形后合金组织基本由破碎的等轴小晶粒构成,形成包含高密度位错的等轴状亚晶;而经UGP变形后,形成类似于冷轧变形金属组织的拉长晶粒和具有较大取向差的包含高密度位错的带状亚结构。与UGP相比,CGP更有利于晶粒细化和形成等轴晶粒。     

低压脉冲磁场对2024铝合金凝固组织的细化

在2024铝合金的凝固过程中施加低压脉冲磁场处理,研究了低压脉冲磁场作用下2024铝合金凝固组织的变化,考察了浇注温度和放电电压对2024铝合金凝固组织中α-Al相形貌和尺寸的影响.结果表明,在低压脉冲磁场的作用下,2024铝合金凝固组织中的初生a-Al相和共晶组织均显著细化.浇注温度越接近液相线温度,初生α-Al的平均晶粒尺寸越小.随着放电电压的升高,初生α-Al的平均晶粒尺寸逐渐减小,当放电电压为250 V时,平均晶粒尺寸达到最小值.     

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.