热处理对选区激光熔化GH3536合金晶界与拉伸行为的影响

采用选区激光熔化制备了GH3536合金,并分别进行固溶处理和热等静压处理,研究不同热处理手段对GH3536合金的组织形貌、晶界形态及室温拉伸行为的影响。结果表明:沉积态试样的组织由超细柱状亚晶粒与熔池界组成,存在气孔与微裂纹等缺陷;选区激光熔化试样分别经固溶处理和热等静压处理后,二者致密度均上升,组织转变为由交替分布的大小不等等轴晶粒组成,但热等静压的沿晶界析出M_(23)C_6相,形成锯齿状的弯曲晶界;沉积态试样的拉伸性能表现出各向异性的特点,固溶处理可消除拉伸性能的各向异性,但抗拉强度和屈服强度均有下降,延伸率明显上升。热等静压态试样与固溶态试样相类似,但其抗拉强度、屈服强度和延伸率均有进一步的提高;3种形态合金的断裂机制均为微孔聚集型的韧性断裂。     

后处理对选区激光熔化成形K536合金显微组织及力学性能的影响

采用选区激光熔化技术成形K536合金并对其进行后处理,分别分析了沉积态、退火态、退火+固溶态、退火+固溶+热等静压态合金试样的显微组织和力学性能。结果表明:沉积态试样横、纵向截面均产生微裂纹;退火态试样的横向截面组织为等轴晶,纵向晶粒形态为柱状晶,且晶粒尺寸波动较大,形成了交替分布的细晶区和粗晶区;退火+固溶态试样发生部分再结晶,在再结晶部分可以观察到孪晶的存在,且出现明显的等轴晶组织,晶粒大小不均匀,晶界析出物呈长条状形态;经热等静压处理后试样的晶粒明显增大,沉积态产生的裂纹基本愈合,且高温持久性能指标达到ASTM标准要求,其晶内析出的碳化物分布均匀,晶界处的碳化物呈链状分布。     

固溶温度对7075铝合金组织及高周疲劳性能的影响

通过对7075铝合金进行不同温度（450、465、480和495 ℃)的固溶处理,研究了固溶温度对该合金的硬度、室温拉伸性能及高周疲劳性能的影响,并用光学显微镜和扫描电镜对合金显微组织及疲劳断口进行观察。结果表明,随着固溶温度的升高,合金组织发生不同程度的静态再结晶和晶粒长大,合金硬度和拉伸强度均先升高后降低,480 ℃固溶处理后达到最高;疲劳极限随着固溶温度的升高先降低后升高,495 ℃固溶处理后达到最高。疲劳裂纹主要起源于粗大残留相处,扩展过程中产生的二次裂纹可降低裂纹扩展的驱动力,进而降低合金的裂纹扩展速率,提高合金疲劳性能。     

FGH4113A合金的双性能热处理组织与力学性能研究

利用扫描电子显微镜（Scanning Electron Microscope,SEM）、光学显微镜（Optical Microscope,OM）、拉伸、蠕变、疲劳试验机等研究了一种新型镍基粉末高温合金FGH4113A（WZ-A3）在两种热处理状态下的显微组织和力学性能,为双性能热处理研究提供组织与力学性能依据。结果表明：FGH4113A合金在双性能热处理中,过固溶与亚固溶态组织与力学性能具有明显的双模特性;室温下,亚固溶态相比过固溶态屈服强度高10.6%,800℃下,过固溶态相比亚固溶态屈服强度高11.7%;与同样是亚固溶或过固溶的其它合金相比,FGH4113A的拉伸强度优于ME3合金,与LSHR合金相当;FGH4113A合金在750℃/450MPa的蠕变变形以位错滑移机制主导,弥散分布的小尺寸硼化物有助于蠕变性能的提高,其蠕变性能全面超过ME3合金,与LSHR合金相当;过固溶态的粗晶组织在裂纹扩展中具有更长的滑移带,在循环载荷中具有较低的累积损伤,抗裂纹扩展能力优于亚固溶态;过固溶态的裂纹扩展断口呈现穿晶断裂特征,亚固溶态由于细晶粒边界的一次γˊ的存在降低了晶界的抗裂纹扩展能力,断口较粗糙,呈现沿晶-穿晶混合断裂特征。     

喷射成形Al-Zn-Mg-Cu合金热处理工艺与力学性能

利用喷射成形技术制备了超高强Al12Zn2.4Mg1.1Cu合金.对合金进行热挤压,在不同固溶温度和时间下对挤压合金进行固溶处理,并进行力学性能测试.结果表明,挤压态合金存在着大量的第二相颗粒,为MgZn2相和富铜相,合金微观组织中包括微米级晶粒和纳米级晶粒.合金进行T6热处理后,抗拉强度为749.6 MPa,延伸率为10.9%,拉伸试样的断口分析表明,合金的断裂方式主要为穿晶断裂.     

热处理工艺对GH4151合金冲击性能的影响

采用冲击实验研究了不同温度固溶处理及固溶和双级时效处理对GH4151合金冲击性能的影响，采用光学显微镜、扫描电镜和透射电镜等观察了合金经不同工艺处理后的显微组织、析出相和断口形貌。结果表明：对于仅固溶处理的合金，当固溶温度低于1140℃时，其冲击韧性值的变化不大，固溶温度高于1140℃时，冲击韧性值随固溶温度的升高而增加，断裂过程以裂纹的稳定扩展区为主，断口呈韧性断裂。对于固溶时效处理的合金，当固溶温度低于1160℃时，冲击韧性值的变化也比较稳定，固溶温度高于1160℃时，冲击韧性值随固溶温度的升高而降低，断裂过程不存在裂纹的稳定扩展区，断口呈典型的沿晶脆性断裂。这主要是因为当固溶温度低于1140℃时，合金的晶粒尺寸变化不大，而在1140℃以上时晶粒尺寸明显增大；双级时效后，当固溶温度高于1160℃时，晶界上连续或不连续分布的第二相显著降低了合金的冲击韧性。     

固溶对GH4169合金晶粒尺寸与力学性能的影响

探索了固溶温度与时间对GH4169合金晶粒长大行为的影响,测试了不同固溶温度下合金的拉伸及冲击性能。结果表明:GH4169合金在低于1020℃固溶,残留δ相阻碍晶粒长大,固溶保温时间越短,晶粒不均匀因子增加越明显。当固溶温度高于1020℃,δ相充分溶解,不同保温时间下的晶粒不均匀因子都显著降低。随晶粒尺寸的增加,GH4269合金拉伸性能降低,但冲击韧性随固溶温度增加而增加。这主要是晶界上δ相的回溶,避免了裂纹沿晶界扩展。     

高铌TiAl合金双态组织室温断裂行为研究

通过对高铌TiAl合金双态组织的缺口试样进行原位拉伸、相应的断裂表面SEM观察,研究其拉伸断裂机制和裂纹扩展的动态过程.结果表明,高铌TiAl合金双态组织的断裂模式主要是穿晶解理断裂;合金的断裂过程是主裂纹首先起裂,微裂纹的产生、扩展和连接主裂纹,直至断裂;在裂纹扩展过程中,尖端附近区域范围内的γ相晶粒内易形成微裂纹,为其断裂过程的一个明显特征;对于双态缺口试样,由于晶粒细小,缺口根部出现应力集中,裂纹扩展路径比较平直.     

固溶处理对GH864合金裂纹扩展速率的影响

研究不同固溶处理后GH864合金650℃裂纹扩展速率的变化规律。结果表明:随晶粒尺寸和固溶温度增加,裂纹扩展速率呈先降低后增加的趋势。根据多组试验数据拟合得到GH864合金晶粒尺寸与裂纹扩展速率的关系式,预测GH864合金晶粒尺寸在100μm左右,抗裂纹扩展能力可能存在最佳值。同时得到GH864合金固溶温度与裂纹扩展速率的关系式。用不同固溶温度将裂纹扩展速率变化规律划分为5个区域,低于固溶温度1080℃裂纹扩展速率随固溶温度增加而降低,1080℃固溶处理后合金的裂纹扩展速率最低,高于固溶温度1080℃裂纹扩展速率随固溶温度增加而增加。精准控制固溶温度可得到合适的晶粒尺寸和较好抗裂纹扩展能力。     

GH864合金显微组织与力学性能的关联性

通过对GH864合金进行不同的固溶处理及时效处理,研究合金中g￠相的含量变化规律及碳化物回溶析出规律,及其对合金晶粒度的影响和对拉伸性能、蠕变性能及裂纹扩展性能的影响。结果表明,相同热处理制度下,晶粒越均匀细小,强度越高;晶粒尺寸越大,裂纹扩展速率越低;在960~1080 ℃范围内,g￠相含量随固溶温度的升高而降低,经过时效处理后g￠相含量趋于一致,此过程冷却介质对g￠相含量影响不显著;g￠相和碳化物交互作用影响合金晶粒尺寸长大,在1020 ℃以下固溶处理,晶粒长大十分缓慢。此外,合金的晶粒度尺寸对蠕变性能影响显著,存在最佳晶粒度以使性能发挥最优。     

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.     

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.     

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.