碳对高温钛合金组织稳定性的影响

结合实验研究,分析了碳合金化对高温钛合金显微组织、高α+β相区、时效过程中α2和硅化物析出的影响机制及其碳化物的稳定性。α+β相区再结晶,碳化物主要在β转变组织中析出以及碳化物的百分数取决于初生α(αp)体积分数;β相区热处理,碳化物的析出阻碍β晶粒的长大。碳的加入延缓αp体积分数随温度的变化速度,扩大高温钛合金的高α+β相区;同时降低αp相Al的浓度,增加β转变组织中Al和Mo的浓度,导致αp相内α2颗粒直径逐渐减小,颗粒间距增大。β相与碳化物之间的包析反应是碳化物溶解的主要动力。     

热处理工艺对Ti80合金显微组织的影响

用X射线衍射仪(XRD)、扫描电镜(SEM)、透射电镜(TEM)等研究Ti80合金在3种热处理工艺下的显微组织与硬度。结果表明:当热处理工艺由900℃×1 h/AC改变至980℃×1 h/AC时,合金由等轴组织转变为双态组织,并伴随着初生α相的减少和球化、β相的增多、次生α相与α'马氏体形态的转变,但合金元素固溶规律无变化;经1020℃×1 h/AC热处理后,合金形成片层组织,初生α相消失、次生α相呈长针丛状在粗大的原始β晶粒内平行分布,此时α'板条马氏体与α'孪晶马氏体共存且合金元素分布较均匀;随热处理温度的升高,合金硬度先降低后升高。     

Ti-55531合金变形及断裂行为的原位SEM分析

采用原位SEM拉伸方法对比分析了Ti-55531合金片层和双态组织静载下的变形及断裂行为。结果表明,静载下α相的特征参数对该合金的形变、裂纹萌生及扩展有强烈影响。片层组织中粗大次生αs片较软,αs片最先变形促进位错滑移,位错运动至次生αs和残留βr的界面处堆积,塑性变形导致局部应力集中促进裂纹萌生,并沿αs/βr相界面扩展。双态组织中初生等轴αp是相对最软相且尺寸较大,位错滑移自由程较大,易启动多系滑移,αp内不同位向的滑移线交割促进应力集中,部分位错在αP/βtrans界面处堆积产生应力集中,两者导致微裂纹萌生于αp内及αp/βtrans界面,并沿αp/βtrans界面和αp聚集处扩展。     

热处理工艺对TC4钛合金组织和性能的影响

研究了不同热处理条件下TC4合金的微观组织和力学性能.结果表明,退火处理后,组织由α相与α相晶粒间弥散的细小等轴状β所组成,强度、硬度降低,韧性提高;在TC4两相区进行固溶处理,初生α相含量减少,形成了针状的马氏体α"组织,β相则由细小的等轴状逐渐转变为层片状,使得合金强度、硬度提高,伸长率呈下降趋势;时效处理后,针状的马氏体α"和亚稳态的β相将发生分解,转变成稳定的弥散的α相和β相,使合金综合性能得到改善.     

热加工工艺对Ti-1300合金轧制棒材显微组织的影响

研究了轧制温度、变形量以及热处理工艺对Ti-1300合金显微组织的影响,并讨论了热加工工艺与合金组织结构以及形貌之间的联系规律。结果表明:两相区轧制后的加工态Ti-1300合金主要由等轴的β相和球状α相组成,随轧制温度向合金相变点温度的升高,α相逐渐溶解在β基体上,因而β单相区轧制的合金主要由等轴的β相晶粒组成,而合金的晶粒随变形量的增加而破碎越充分,组织也更加细小、均匀。两相区固溶处理后的Ti-1300合金在晶界和晶间析出球状以及条状α相,弥散分布于亚稳定β基体,产生细晶强化效应,而β单相区固溶处理后的合金主要由平均晶粒尺寸为60μm的等轴β相组成。两相区固溶处理后的时效态Ti-1300合金的组织主要由条状初生αp相、针状次生αs相以及β基体组成,热轧温度和变形量对时效态Ti-1300合金中αp相的形貌特征影响较小,但αp相和αs相都随时效温度的升高而不同程度的长大,针状次生αs相弥散分布在β基体上。     

β相区凝固的铸造γ-TiAl基合金的微观组织(英文)

采用光学显微镜(OM)、扫描电镜(SEM)、透射电镜(TEM)及差示扫描量热仪(DSC)研究Ti-43Al-4Nb铸态合金及其热处理态合金的显微组织以及相转变行为。结果表明:通过从β相区凝固的方法可以获得组织细小的铸态Ti-43Al-4Nb合金;凝固过程中γ晶能够直接从β相中形核,β相与γ相沿初始α晶界共存,有效地抑制了铸态Ti-43Al-4Nb合金晶粒的长大;Ti-43Al-4Nb合金在凝固过程中的相转变顺序为L→L+β→β→α+β→α+βr→α+γ+βr→(α2+γ)片层+γ+βr;经1250℃、16h热处理后,Ti-43Al-4Nb合金的显微组织与铸态组织相比有一定程度的粗化;由于Nb元素的充分扩散以及β相的非平衡状态,经过上述热处理过程后残余β相能够被完全消除。     

时效热处理对α挤压态TiAl合金显微组织的影响

研究了不同时效热处理后挤压态γ-TiAl合金在高温期间显微组织的稳定性.结果表明:在1 330 ℃将Ti-47Al-2Cr-2Nb-0.15B合金挤压得到近片层组织,将α单相区热处理后得到全片层组织,在700～1 000 ℃停留不同时间后进行时效处理,从平行挤压方向上观察,在全片层晶界处出现细小γ晶粒,随着时效时间的延长,γ晶粒增大,其体积分数增加;全片层晶粒晶界处的非连续界面处首先发生不连续粗化,最终转变为拉长的γ晶粒,然后层片晶团内部各片层之间的连续界面处发生连续粗化,具有小曲率的薄α2片层开始以逐步变薄的方式断开和溶解,γ片层得到粗化.     

Mg-9Li-3.57Al-0.5Si-0.25Ca合金的组织转变与力学性能

为了提高镁锂合金的强度,采用普通重力铸造法制备了Mg-9Li-3.57Al-0.5Si-0.25Ca合金,考察该合金经均匀化热处理及轧制变形后的微观组织演变及力学行为变化。结果表明,铸态Mg-9Li-3.57Al-0.5Si-0.25Ca合金主要由β-Li基体、α-Mg相、以及分布于α-Mg/β-Li相界、基体的AlLi大颗粒,少量的Mg Li2Al、Mg_2Si和(Mg,Al)_2Ca相组成。合金经不同时间均匀化处理后,β-Li基体及界面处的AlLi大颗粒溶解,而在α-Mg相内析出纳米AlLi颗粒、并逐步长大;同时长条状α-Mg相从β-Li基体中析出并逐步合并长大。再经热轧后,α-Mg相拉长细化;α-Mg相内、相界面处大量AlLi相回溶,消除了界面处大颗粒聚集分布状态;同时在α-Mg相、β-Li基体内形成高密度均匀弥散分布的纳米颗粒强化相,合金得到了有效强化。热轧合金的力学性能大幅度提高,其抗拉强度、屈服强度、伸长率分别达到216 MPa、164 MPa和9.51%。     

热变形高铌Ti-Al合金获取全片层组织的热处理工艺

研究了热变形高铌Ti-Al合金获取全片层组织的热处理工艺及转变机理,提出了新的热处理工艺为:1480℃×10min→1345℃×20min→900℃×2h,空冷。采用新工艺热处理时可使高铌Ti-Al合金中在β相与α相区两次重新形核长大,破坏了原始变形组织中晶粒间的取向关系,从而得到了均匀的α相,因而新工艺热处理后得到较为均匀细小的全片层组织。     

冷却方式对BT25y钛合金显微组织和拉伸性能的影响

采用金相(OM)、扫描电镜(SEM)、X射线衍射(XRD)、透射电镜(TEM)等技术研究了固溶处理后的冷却方式对BT25y钛合金显微组织和拉伸性能的影响。结果表明,950℃固溶处理后空冷得到的组织由α相与β转变组织组成,水淬与油淬组织主要由等轴α相、针状α'相与羽毛状α'马氏体相组成;与油淬相比,水淬得到的α'相的晶格常数a值减小,b值增大。经时效处理后,固溶后空冷组织的相组成没有变化,油淬与水淬组织中的马氏体相分解为稳定的α相与β相。室温拉伸结果表明:相对于空冷组织,油淬与水淬组织的屈服强度与抗拉强度明显升高,而延伸率明显低于空冷组织,该现象与原始β晶粒内析出的次生α相的弥散程度及界面密度有关。     

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.