粉末冶金TiAl基合金显微组织及力学性能的研究

采用粉末冶金方法制备多种成分的ＴｉＡｌ基合金,并研究其显微组织及室温、高温力学性能,结果表明,采用粉末冶金方法能制备成分均匀、显微组织细小的Ｔｉ－Ａｌ－Ｃｒ－Ｎｂ系列合金。添加合金元素对粉末冶金ＴｉＡｌ基合金的显微组织具有显著影响。粉末冶金ＴｉＡｌ基合金的力学性能与其显微组织有密切的关系,显微组织越细小,其室温强度及延性越高,但在高温下,其屈服强度随晶粒尺寸增加而增加。所制备出的Ｔｉ－４７Ａｌ－３     

γ－TiAl基合金的显微组织与机械性能

简要介绍了γ－ＴｉＡｌ基合金性能与其显微组织的关系以及该合金的变形、断裂、韧化机制，由此归纳出了γ－ＴｉＡｌ基合金的塑化、初化途经。指出，合金化和显微组织的控制是改善该合金性能的重要方法。文章还探讨了γ－ＴｉＡｌ基合金今后的研究工作重点。     

TiAl基合金热处理显微组织缺陷

研究了等温锻造和热处理后ＴｉＡｌ基合金显微组织中晶粒尺寸不均匀参数，讨论了这种缺陷对ＴｉＡｌ基合金室温抗拉笥能的影响，提出了这种显微组织缺陷形成机理。     

Ti3Al＋TiAl片导组织的不连续粗化转变

为细化铸造ＴｉＡｌ基合金的显微组织,将成分为Ｔｉ－４４．９Ａｌ和Ｔｉ－４４．３Ａｌ－３．０Ｃｒ的两种合金在略高于Ｔｉ－Ａｌ共析温度的１１５０℃刊物 保温处理。     

Ti_3Al TiAl片层组织的不连续粗化转变

为细化铸造ＴｉＡｌ基合金的显微组织,将成分为Ｔｉ４４．９Ａｌ和Ｔｉ４４．３Ａｌ３．０Ｃｒ（摩尔分数,％）的两种合金在略高于ＴｉＡｌ共析温度的１１５０℃进行长时保温处理。结果表明,保温一定时间后,两种合金中的Ｔｉ３Ａｌ＋ＴｉＡｌ片层组织都会发生不连续粗化转变,这种转变的结果能在一定程度上细化合金的晶粒尺寸,其中Ｔｉ４４．３Ａｌ３．０Ｃｒ合金的晶粒细化效果更佳。进一步的研究表明,二元Ｔｉ４４．９Ａｌ合金中的片层组织的不连续粗化转变近似符合最大熵增率原理和Ｌｉｖｉｎｇｓｔｏｎ的稳态扩散模型,其转变控制因素为晶界扩散控制;合金元素Ｃｒ的加入,原始片间距的细化及表面预变形都会大大促进这种不连续粗化转变过程。     

TiAl基金属间化合物的显微组织与断裂韧性

通过复合热机械处理新工艺，得到了细小均匀的ＴｉＡｌ基合金的显微组织，并研究了这些显微组织的断裂韧性。结果表明：全层片组织的断裂韧性最高，近层片组织的稍次，双态组织的最低。最后分析了ＴｉＡｌ基合金的显微组织被均匀细化的原因，并讨论了各种显微组织的断裂机制     

超塑性TiAl基合金的显微组织特征

采用金相显微镜,扫描电镜和透射电镜,对超塑性拉伸变形后的Ｔｉ－１１Ａｌ－３Ｃｒ－０．５Ｍｏ（质量分数）合金的显微组织进行了观察和分析。研究发现,ＴｉＡｌ基合金在超塑性变形过程中发生了动态再结晶现象,动态再结晶使晶粒显著细化。透射电镜观察结果表明,γ晶粒内有位错运动,位错运动导致γ晶粒内形成位错墙,位错网。这些显微组织特征与ＴｉＡｌ基合金的超塑性变形机理有着密切的关系。     

添加Sb改善TiAl基合金高温强度

添加Ｓｂ改善ＴｉＡｌ基合金高温强度由于ＴｉＡｌ基合金具有优良的高温性能，因此它很有希望成为１０００℃以上使用的结构材料。日本正在考虑航空—航天飞机工程计划，拟用ＴｉＡｌ基合金做结构材料，这就需要提高ＴｉＡｌ基合金在１１００℃的高温强度，研究发现加入Ｓ...     

PST双相TiAl类单晶中的微孪晶变形

利用透射电子显微镜研究了ＰＳＴ双相ＴｉＡｌ类单晶中的微孪晶变形行为，研究结果表明，孪晶面为（１１１），是由（α／６）Ｓｈｏｃｋｌｅｙ不全位错在（１１１）面上运动产生的，当该位错遇到到互在孪晶关系的两片ＴｉＡｌ界面时，将在另一片ＴｉＡｌ相中诱发出新的微孪晶，其孪晶系统不变，这说明互成孪晶关系的ＴｉＡｌ相界面对微孪晶变形阻碍作用不大，本文讨论了微孪晶变形对材料变形的影响。     

EFFECT OF Cr ON MICROSTRUCTURE OF Ti_3Al＋TiAl ALLOYS

研究了Ｔｉ－４４．９Ａｌ（ａｔ．－％）和Ｔｉ－４４．３Ａｌ－３Ｃｒ（ａｔ．－％）合金的铸态组织及其在热处理过程中的变化。结果表明：Ｃｒ增加了Ｔｉ－Ａｌ合金中ＴｉＡｌ（γ）相的含量，促使Ｔｉ３Ａｌ（α２）相由片状变成块状；加速了α２＋γ片状组织的不连续粗化过程，形成了尺寸较小的新生α２＋γ晶。因此，加Ｃｒ和１１５０℃长时热处理是细化α２＋γ两相合金铸态粗晶组织的有效途径；Ｃｒ促进有序体心立方β２相的     

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.     

Rheology Feature of Simple Metal Melt

The rheology feature of Sb, Bi melt and alloys was studied using coaxial cylinder high-temperature viscometer. The results showed that the curve of torsion-rotational speed for Sb melt presents a linear relation in all measured temperature ranges, whereas for the Bi melt, the curve presents obvious non-Newtonian feature within the low temperature range and at relative high shear stress. The rheology feature of Sb80Bi20 and Sb20Bi80 alloy melts was well correlated with that of Sb and Bi, respectively. It is considered that the rheology behavior of Sb melt plays a crucial role in Sb80Bi20 alloy and that of Bi melt plays a crucial role in Sb20Bi80 alloy.