Mo含量对一种镍基单晶高温合金显微组织和持久性能的影响

采用螺旋选晶法制备镍基单晶高温合金，研究了Mo含量（质量分数）分别为2％，3％，4％时合金的显微组织和高温持久性能．结果表明：3种成分合金的铸态组织均由γ和γ′相组成．1100℃，500h热暴露后，4％Mo合金中的μ相大量析出并长大，3％Mo合金中只有少量μ相析出，2％Mo合金中不析出μ相．析出的μ相主要由Mo，Re，W，Cr，Co和Nb等元素组成．其中，Mo形成μ相倾向最强；Re，W和Cr次之；Nb和Co最小．大量棒状μ相的析出严重损害了合金的高温持久性能，少量“相不降低合金的高温持久性能．考虑到Mo的固溶强化作用使合金高温持久性能升高，对于Ni-5Cr-10Co-4W-3Re-5.6Al-8Ta-1Ti-0．5Nb基础成分合金，最佳的Mo含量为3％．     

Nb在铁基高温合金中的作用

研究了Nb在Fe-Ni-Cr-W-Mo-Ti合金中的中高温强化作用。当Nb含量低于1.22wt-％时,合金的650℃拉伸强度、塑性、持久寿命和疲劳极限随Nb含量升高而提高。Nb促使MC相均匀分布,细化晶粒,增加γ′相的数量和提高其稳定性。当Nb含量为1.22wt-％时,小颗粒Laves相在晶界上弥散析出,有利于合金的综合性能;只有当Nb含量过高时,Laves相在晶界过量析出,才使合金性能恶化。     

含锆铝合金的力学性能和强化机理

研究了高强铝合金的力学性能与Zr含量的关系，计算了合金的各种强化因素值。研究发现：合金的抗拉强度巩和屈服强度如σ0.2均随Zr含量的增加而增大，增幅分别达到11．8％和12．6％；合金延伸率δ在Zr添加量不高时随Zr含量的增加而增大，在Zr含量为0．06％时出现峰值，随后合金延伸率δ逐渐稳定在8％左右。结合合金显微特征，合金强化机理主要包括晶粒细化、颗粒弥散强化及形变强化，在Zr含量为0．16％的合金中相应的强化值分别为21.35和14MPa.     

Nb表面合金化对Ti6A14V腐蚀行为的影响

采用失重法和电化学扫描法研究了等离子表面合金化技术在Ti6A14V（TC4）合金表面形成的Ti—Nb合金层及基体材料的腐蚀行为，分析了Nb的渗入对Ti6A14V耐蚀性的影响．失重法研究表明：在10％H2SO4和10％HCl溶液中Ti—Nb合金层较基体耐蚀性提高，在10％NaCl溶液中无明显变化；电化学腐蚀研究表明，在5％H2SO4、5％HCl、3．5％NaCl溶液中，Ti—Nb合金层耐蚀性较基体均有不同程度的提高．     

微量Sc元素对Al-Cu合金组织与性能的影响

采用拉伸力学性能测试、扫描电镜与能谱分析等方法，研究了不同量稀土元素Sc对Al-4Cu合金组织与性能的影响。结果表明：稀土元素Sc能够细化Al-4Cu合金的晶粒组织，改善枝晶网胞；当Sc含量小于0．2％时，Al-4Cu合金的抗拉强度δb和屈服强度δ0.2提高约20MPa；当Sc含量为0．3％～0．4％时，抗拉强度δb和屈服强度δ0.2有所降低；当Sc含量为0．5％时，抗拉强度δb和屈服强度δ0.2又有所升高，但低于未添加Sc的Al-4Cu合金；Sc对合金的伸长率几乎没有影响。微量Sc元素添加到Al-4Cu合金中，当Sc含量小于0．2％时，基本上以固溶的形式溶入合金基体中；当Sc含量为0．3％。0．5％时，除部分固溶于Al基体中外，大部分形成起强化作用的Al3Sc相及交互作用AlCuSc相，AlCuSc相是Al-Cu-Sc系合金中的有害相，它使合金的力学性能在一定程度上有所降低。     

元素Si对TiAl合金抗氧化性能的影响

研究了元素Si对不同Nb含量TiAl合金抗氧化性能的影响．结果表明，合金中Nb含量越低，Si对合金抗氧化性能的提高作用越明显．主要表现为Si促使二元合金形成连续致密的Al2O3层及使不同Nb含量合金表层氧化物更加均匀细小．因而随Si含量的增加，TiAl合金的氧化增重速率系数降低，氧化速率下降．运用等温氧化增重实验、X射线衍射和扫描电镜等手段对Si的作用进行了分析讨论．     

Zr、Nb复合变质剂对Fe—Ni彭胀合金凝固组织及力学性能的影响

研究了添加Zr、Nb复合变质剂对Fe-Ni膨胀合金线坯凝固组织和力学性能的影响。结果表明，单独添加0.3％的Zr或Nb．其线坯中等轴晶比例分别增加到25％和50％，其强度和塑性随等轴晶比例增加而提高。添加0.3％的Zr、Nb复合变质剂，线坯为完全的细小等轴晶，其强度和塑性均优于单独添加Zr或Nb的性能，与同规格的退火态Fe-Ni膨胀合金热轧盘圆力学性能相当。研究认为：Zr、Nb复合变质剂的作用是显著增加了合金凝固过程中的形核核心，并在晶界上形成Zr、Nb化合物析出相，从而强化晶界，提高韧性，使合金线坯具有较高的强度和良好的塑性。     

ECAP加工中Ti-6Al—7Nb合金晶界取向对其力学性能的影响

Ti-6Al-7Nb合金与Ti-15Al-4V合金相似，但是具有更强的惰性，是专为医疗应用而设计的。然而，与Ti-15Al-4V合金不同的是，该合金为近α型合金，β相含量小于5％。     

Nb对ZG45Cr2MnSiMo组织和性能的影响

针对球磨机衬板材料ZG45Cr2MnSiMo，通过加入合金元素Nb，研究其对组织和性能的影响。结果表明，当Nb含量为0．06wt％，经900℃淬火、250℃回火时，试样的硬度为HRC54．5，冲击韧度为28．5J／cm^2，组织为板条状马氏体＋少量残余奥氏体＋微量碳化物，并获得良好的强韧性，耐磨性与不加Nb元素的试样相比提高32．67％。     

机械研磨Tix(Cu0.45Ni0.55)94-xSi4B2合金系的玻璃形成范围

利用X射线衍射、透射电子显微镜和差示扫描量热计分析表征了Tix(Cu0．45Ni0．55)94—xSi4B2(x＝50，60，70，75，80)合金粉末高能球磨后产物的相组成．结果表明，合金成分在50≤x≤70范围，球磨产物主要为非晶相，但仍残留有α—Ti纳米晶体，当x＞70％时，机械研磨仅导致初始晶体相的晶粒细化，形成纳米晶结构，未发生非晶化；不同Ti含量非晶相的晶化行为依赖于合金成分；用2％的V，Zr，Nb元素分别部分替代x＝70和x＝75合金中Ti时，对非晶相形成范围的扩展没有明显的作用．     

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.