Ti6Al4V钛合金超声波冷锻/微弧氧化涂层的制备及耐磨性能

为了提高生物医用钛合金的耐磨性,利用超声波冷锻技术(UCFT)作为预处理,采用微弧氧化(MAO)技术制备出具有生物活性的MAO涂层。采用透射电子显微镜(TEM)和原子力显微镜(AFM)测量钛合金UCFT处理后表面纳米晶粒大小和表面粗糙度,采用扫描电子显微镜(SEM)、X射线衍射仪(XRD)和显微硬度计测量涂层的微观形貌、相组成和显微硬度,并在高速往复摩擦磨损试验机上对试样进行摩擦学性能测试。结果表明:超声波冷锻后的钛合金表面晶粒得到细化,平均表面粗糙度仅为36.98nm;UCFT-MAO涂层的显微硬度从330HV0.05提高到518HV0.05,经超声波冷锻预处理后的微弧氧化涂层的摩擦因数降低,UCFT-MAO试样在仿生液中的磨损量仅为基体试样的1/3。超声波冷锻技术作为预处理,显著提高了钛合金微弧氧化涂层的耐磨性能。     

拉应力条件下微弧氧化膜对铝合金腐蚀及电化学行为的影响

为研究在拉应力条件下微弧氧化膜对铝合金腐蚀及电化学行为的影响,采用恒载荷应力环在3.5% NaCl溶液中研究了经微弧氧化（MAO）处理后的7050铝合金（AA7050）应力腐蚀行为。用原位电化学阻抗谱（EIS）的方法评价在拉应力条件下,膜层的腐蚀破坏随浸泡时间的变化,并建立了相应的等效电路模型。结果表明,在3.5% NaCl溶液中,微弧氧化膜在有无拉应力的条件下都可以提高AA7050的耐蚀性和减少AA7050的塑性损失。在400 MPa拉应力条件下,微弧氧化膜的阻抗在应力腐蚀的过程中呈现出先减小后增大,再减小最后趋于稳定的规律;另外,AA7050在有拉应力的条件下,拉应力会促进基体的点蚀形核,提高腐蚀速率,微弧氧化膜的疏松层在拉应力的作用下会失去对基体的保护作用。     

微弧氧化增强镁合金钼酸盐转化膜层的制备

目的提高钼酸盐转化膜的耐腐蚀性能,制备微弧氧化增强的钼酸盐膜层。方法采用化学转化法和微弧氧化法在AZ91D镁合金表面制备钼酸盐转化膜、微弧氧化膜和微弧氧化增强的钼酸盐膜层,研究了膜层的电化学行为和腐蚀失重情况,利用SEM、EDS、XRD和激光共聚焦显微镜对膜层的表面形貌、元素组成、物相组成和粗糙度进行分析。结果 XRD分析表明,钼酸盐膜层经过微弧氧化处理后,所得膜层较微弧氧化膜层多出新相MoSi_2。钼酸盐转化膜层经过微弧氧化处理后,相比于微弧氧化膜层,表面变得平整光滑,孔洞微粒变小,粗糙度降低。钼酸盐转化膜经过微弧氧化处理后,在3.5%NaCl溶液中浸泡48 h,膜层失重最低。通过电化学测试,微弧氧化增强钼酸盐膜层的腐蚀电位较钼酸盐转化膜的腐蚀电位正移0.643 V,较微弧氧化膜的腐蚀电位正移0.419 V,腐蚀电流密度较钼酸盐转化膜降低了3个数量级,较微弧氧化膜降低了1个数量级。结论钼酸盐转化膜经过微弧氧化处理后,膜层的耐腐蚀性能优于钼酸盐转化膜和微弧氧化膜,使镁合金的应用前景有所提高。     

微弧氧化-溶胶凝胶复合表面技术改善铝合金的耐腐蚀性能

通过微弧氧化-溶胶凝胶复合表面处理技术来提高铝合金的耐腐蚀性能,分析了多层凝胶层对6061铝合金耐腐蚀性能的影响。采用扫描电镜（SEM）、X射线衍射仪（XRD）和电化学分析等方法对膜层的表面形貌、化学组成、结构以及耐腐蚀性能进行了表征。研究表明：TiO2溶胶渗入微弧氧化陶瓷膜的微孔以及裂纹中,能有效阻挡腐蚀介质的扩散和渗透;复合处理后的试样较仅微弧氧化处理更平滑、致密;膜层除了γ-Al2O3相外,经高温退火处理后出现TiO2锐钛矿,并形成较好的晶相结构;在3.5%NaCl溶液中的室温电化学行为中,复合处理较微弧氧化处理后的试样自腐蚀电位上升最高约400 mV,自腐蚀电流密度最高减小约3个数量级,极化电阻明显增大;随着凝胶层厚度的增加耐腐蚀性能逐渐增强,但当凝胶层数大于4时,膜层龟裂现象严重,并导致耐腐蚀性能开始下滑。     

微弧氧化处理对铝合金耐霉菌腐蚀特性的影响

在2A12铝合金表面制备了微弧氧化膜层,按照国家军用标准霉菌测试方法对微弧氧化膜层的耐腐蚀性能进行了测试,通过扫描电镜(SEM)、X射线衍射分析(XRD)对铝合金基体及微弧氧化膜层霉菌腐蚀前后的微观结构、相组成进行了表征。结果表明,未经过微弧氧化处理的铝合金表面有少量的霉菌生长,表面产生了一定数量的点蚀坑,长霉等级为1级。经过微弧氧化处理试样表面未发现霉菌生长,长霉等级为0级。微弧氧化处理可以有效提高铝合金表面耐霉菌腐蚀性能,扩大其应用范围。     

LD10铝合金微弧氧化膜的生长及腐蚀性能

采用双极性交流电源在LD10铝合金表面制备出微弧氧化膜。测量了硅酸盐电解液里微弧氧化膜的生长曲线,并分析了微弧氧化膜的结构、成分和相组成。采用浸泡腐蚀试验、醋酸加速盐雾腐蚀试验、动电位极化和电化学阻抗谱(EIS)方法评估了微弧氧化处理前后LD10铝合金的腐蚀性能。结果表明:LD10铝合金微弧氧化膜主要由γ-Al2O3组成,膜外层还有少量非晶相。微弧氧化初期,氧化膜主要以向外层生长为主,且表面粗糙度快速增加。随后膜层向内生长速度逐渐加快,最后阶段微弧氧化膜主要以向内生长为主。微弧氧化处理后LD10铝合金的腐蚀电位提高,腐蚀电流密度下降约2个数量级。微弧氧化膜的阻抗模值|Z|比铝合金基体大幅提高,同时其容抗弧半径远远大于铝合金基体。微弧氧化表面处理显著提高了LD10铝合金的耐腐蚀性能。     

MoS2对2Al2铝合金表面微弧氧化膜层组织和性能的影响

为了提高海洋工业用2A12铝合金的耐腐蚀性能,采用微弧氧化技术在2Al2铝合金表面制备微弧氧化膜层。研究了电解液中MoS_2纳米颗粒的浓度对微弧氧化膜层的结构和性能的影响。研究结果表明:电解液中MoS_2纳米颗粒的浓度对微弧氧化膜层的制备有显著的影响。当MoS_2纳米颗粒的浓度为2.0 g/L时,膜层的表面致密且光滑,膜层的厚度最大;与未添加MoS_2颗粒相比,MoS_2纳米颗粒的掺入显著提高了MAO膜层的耐磨性;此外,电解液中添加2.0 g/L MoS_2纳米颗粒,获得的MAO膜层的耐腐蚀性能最佳。     

大风沙地区铝合金接触网零部件表面处理的优选

目的提高铝合金接触网零部件表面耐磨损性能,以增加其在大风沙地区的使用寿命。方法对接触网零件切割进行试样制备。在硅酸盐体系电解液中,采用20 k W直流脉冲微弧氧化设备对试样表面进行微弧氧化处理,电解液为硅酸盐,氧化时间为30 min。同时制备阳极氧化处理的平行试样。通过硬度测试、摩擦磨损试验以及扫描电子显微镜(SEM)测试,分别评价两种表面处理方式的表面硬度、耐磨性能,利用中性盐雾试验来评价其耐腐蚀性能,并通过扫描电子显微镜来观察两种膜层的差异。结果通过对铝合金接触网进行阳极氧化和微弧氧化处理能明显提高表面耐磨性。阳极氧化膜层硬度为350.3HV,微弧氧化膜层硬度约为阳极氧化膜硬度的4倍,达到1510.8HV。经过HT-600高温摩擦磨损试验机30 min的磨损试验,铝合金基体质量损失2 mg,阳极氧化膜质量损失0.8 mg,而微弧氧化膜的质量损失只有0.15 mg左右,且微弧氧化膜层表现出了更好的耐腐蚀性能。结论微弧氧化膜层能表现出更加优异的耐磨及耐腐蚀性能,因此微弧氧化更适合大风沙地区铝合金零件的表面处理。     

微弧氧化处理对AA7075铝合金在3.5%NaCl溶液中局部腐蚀行为的影响(英文)

采用微弧氧化法在AA7075铝合金上生成氧化铝膜层,并对氧化铝膜层在3.5%NaCl溶液中的腐蚀和应力腐蚀开裂行为进行测试。采用电化学阻抗谱来研究膜层随浸泡时间的变化,构建合适的等效电路图。对常载荷应力腐蚀开裂测试后的试样进行金相观察。结果表明,微弧氧化膜可以有效避免富Cu、Fe金属间化合物相引发的严重局部腐蚀而导致的合金过早失效。     

微弧氧化膜对7050铝合金氢致局部塑性变形的影响

目的改善7050铝合金在湿空气中氢致延迟开裂敏感性高的问题,以延长其使用寿命。方法采用微弧氧化工艺在铝合金表面生成微弧氧化膜,研究微弧氧化膜对高强铝合金氢致局部塑性变形的影响。通过双悬臂梁(DCB)试样恒位移试验,评价微弧氧化膜对7050铝合金应力腐蚀敏感性的影响,通过读数显微镜原位观察和记录裂纹扩展情况。利用扫描电镜观察断口形貌,采用定氢仪分析氢含量。结果经过微弧氧化处理后,7050铝合金氢致局部塑性变形行为明显下降。测得有微弧氧化膜试样的应力腐蚀开裂门槛值KISCC为23.340MPa·m1/2,而无微弧氧化膜试样的KISCC为16.934MPa·m1/2。有膜的裂纹扩展速率为6.378×10–6 m/s,无膜的裂纹扩展速率为1.3612×10–5 m/s。同时微弧氧化膜使铝合金DCB试样中氢的体积分数从0.281×10–6下降到0.163×10-6。结论微弧氧化膜可以降低铝合金裂纹尖端的氢含量,从而抑制铝合金的氢致局部塑性变形。     

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.