30Cr2Ni4MoV低压转子钢的静态再结晶行为

在Gleeble-1500D热模拟实验机上,使用双道次热压缩的方法,研究了30Cr2Ni4MoV低压转子钢在高温变形时的静态再结晶行为。讨论了变形温度、应变、应变速率与原始晶粒尺寸对其静态再结晶的影响。根据实验结果,建立了30Cr2Ni4MoV钢静态再结晶动力学模型以及静态再结晶晶粒尺寸模型。实验结果表明:间隔时间越长、变形温度越高、应变和应变速率越大,静态再结晶体积分数越大;变形温度越低、应变越大、原始晶粒尺寸越小,静态再结晶晶粒越细小。     

50Cr5MoV轧辊钢的静态再结晶行为北大核心CSCD

在Gleeble-3500热模拟机上采用双道次热压缩试验,研究50Cr5MoV轧辊钢高温变形道次间隔时间内的静态软化行为,通过应力补偿法计算静态再结晶体积分数,分析热变形温度、应变速率、变形程度以及初始奥氏体晶粒尺寸对静态再结晶体积分数的影响,并建立50Cr5MoV轧辊钢的静态再结晶动力学模型,获得静态再结晶激活能191.85 k J/mol。结果表明:变形温度、应变速率、变形程度和道次间隔时间对静态再结晶体积分数影响较大,而初始奥氏体晶粒尺寸对静态再结晶体积分数影响很小;将静态再结晶动力学模型的预测值与实测值进行比较,二者吻合较好。     

50Cr5MoV轧辊钢的静态再结晶行为

在Gleeble-3500热模拟机上采用双道次热压缩试验,研究50Cr5MoV轧辊钢高温变形道次间隔时间内的静态软化行为,通过应力补偿法计算静态再结晶体积分数,分析热变形温度、应变速率、变形程度以及初始奥氏体晶粒尺寸对静态再结晶体积分数的影响,并建立50Cr5MoV轧辊钢的静态再结晶动力学模型,获得静态再结晶激活能191.85 k J/mol。结果表明:变形温度、应变速率、变形程度和道次间隔时间对静态再结晶体积分数影响较大,而初始奥氏体晶粒尺寸对静态再结晶体积分数影响很小;将静态再结晶动力学模型的预测值与实测值进行比较,二者吻合较好。     

GH696合金动态再结晶模型

采用热模拟压缩试验研究GH696合金在变形温度为880~1020℃、应变速率为0.01~10.0 s~(-1)、变形程度为30%~60%条件下的高温变形行为。采用金相显微镜对GH696合金高温压缩变形后的显微组织进行观察。结果表明:较高的变形温度和较低的应变速率有利于GH696合金的动态再结晶。采用加工硬化率-流动应力曲线确定GH696合金的动态再结晶临界应变,应用Avrami方程建立GH696合金的动态再结晶体积分数模型,并根据合金的金相定量试验结果建立GH696合金的动态再结晶晶粒尺寸模型。     

GH4169高温合金热变形力学性能研究

通过热模拟实验对GH4169高温合金热态变形过程中的力学性能进行研究,分析了初始晶粒尺寸、应变速率、变形温度等对GH4169合金热变形时峰值应力的影响。结果表明,该合金的峰值应力随应变速率的增大而增大,随变形温度的增大而减小。该合金的流动应力随初始晶粒尺寸的增大而增大,其原因是该合金在热变形过程中发生了动态再结晶。确定了基于初始晶粒尺寸的峰值应力与热变形参数之间的关系式,确定了GH4169合金的变形激活能。     

GH4169合金热加工过程中的显微组织演化数学模型

采用Thermecmastor—Z型热加工模拟试验机对GH4169合金热态变形过程中(温度范围为960～1020℃，应变速率范围为10^-2～50s^-1，等效应变范围为0．357～0．916和变形后高温滞留阶段内(滞留时间为0～15s)的显徽组织演化过程进行了实验研究，定量地测定了试样内的动态再结晶晶粒尺寸和再结晶体积分数。根据实验结果，指出了GH41．69合金热加工过程中的主要显微组织演化过程是动态和亚动态再结晶，确定了峰值应力和峰值应变与锻造热力参数间的关系，建立了动态再结晶和亚动态再结晶过程的运动学方程和晶粒尺寸演化模型，从而为预测和控制GH4169合金锻件的组织性能提供了依据。     

大型冷轧辊Cr5钢的静态再结晶行为及其动力学模型

为了研究冷轧辊Cr5钢在不同形变条件下的静态再结晶行为,利用热模拟试验机Gleebel-1500D进行了双道次热压缩试验。探讨了变形温度、变形程度、应变速率和初始奥氏体晶粒尺寸在不同间隔时间内对其静态再结晶行为的影响。结果表明:变形程度、应变速率对静态再结晶体积分数影响最大,变形温度次之,初始奥氏体晶粒尺寸影响较小。对于微观组织演化,变形温度和初始奥氏体晶粒尺寸对其影响最大,变形程度和应变速率影响较小。依据试验结果,建立Cr5钢的静态再结晶动力学模型,通过模型预测结果和试验结果比对得到其相关系数达到了0.9895,表明两者有较高的契合度。     

GH4169合金惯性摩擦焊接过程组织计算与预测

以高性能航空发动机涡轮盘和压气机盘为背景，采用有限元数值模拟方法，对GH4169合金模拟件的惯性摩擦焊接过程进行了分析与计算，基于金属塑性变形的物理基础，建立了GH4169合金惯性摩擦焊接过程显微组织的演化模型；通过高温合金在热成形过程中的再结晶发生条件，再结晶体积分数、晶粒尺寸与热力参数（应变速率、应变程度、成形温度）之间的映像关系，对惯性摩擦焊接热力影响区的再结晶组织进行了模拟计算。从而为合理地制定焊接热力规范，提高GH4169合金的焊接性能和接头质量提供了参考。     

形变参数对GH4169合金热变形行为的影响

利用Gleeble-1500热模拟试验机,研究了GH4169合金在变形温度为900～1100℃、应变速率为0.1 s-1、1 s-1、20 s-1、最大变形量高达70%条件下的高温变形行为,建立了GH4169合金的高温变形流动应力模型,分析了变形工艺参数对合金晶粒再结晶的影响规律。结果表明:随变形温度的降低和应变速率的增加,合金变形抗力显著增加;当变形量超过临界变形量时,随着变形量增加或变形温度的提高,合金的再结晶程度逐渐增加;然而,变形速率的变化,对该合金再结晶影响较为复杂。     

晶粒度对690合金热变形特性的影响

利用物理模拟实验方法对具有不同晶粒尺寸的690合金试样进行热压缩变形实验,变形温度范围为1100～1200℃,应变速率分别为0.1,1,10s-1,获得了合金的流变应力数据,并对合金变形后的组织特征进行了分析,建立了包含初始晶粒度参数的本构关系模型。结果表明:晶粒尺寸增大使690合金高温变形时的流变应力增加,发生动态再结晶的临界应变增大,动态再结晶体积分数减小,根据所建立的流变应力本构模型计算出的流变应力值与实验值相近,从而完善了690合金的热变形本构方程。     

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.     

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.     

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.     

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.