纯铜热化学反应热喷涂陶瓷/渗铝复合涂层耐蚀性研究

采用火焰喷涂技术在铜基体表面先后喷涂渗铝层和陶瓷涂层,并加热保温,制备成铜基陶瓷/渗铝复合涂层。用XRD和SEM对涂层进行组织结构分析和形貌观察,并测试涂层的硬度、抗热震性和耐蚀性。结果表明,复合涂层中有Cu9Al4、Cu5Zn8、Cu3Ti等新相生成;渗铝层部分有γ2相（Cu9Al4）析出且涂层与基体结合紧密;复合涂层的硬度为82～87 HRE,其耐热震次数可达50次以上;复合涂层封孔后的耐酸蚀能力提高到基体的16倍,耐盐蚀能力提高到基体的25倍;极化试验表明,复合涂层抗电化学腐蚀能力显著增强,其耐蚀性能远优于纯铜渗铝层和单纯陶瓷涂层。     

表面纳米化对材料性能影响的研究进展与展望

工程零部件失效常源于表面,微组织结构显著影响甚至决定工程零部件使役性能,表面纳米化技术可诱导材料微组织结构变化产生纳米晶结构表面层,增大表层残余压应力,对材料性能有极其重要的影响。首先综述了表面纳米化诱导微组织结构变化的过程及机理,诱导材料产生晶粒细化、位错运动、残余压应力增大、相变等微观变化,诱因有塑性变形、温度变化、元素渗入等。其次归纳了表面纳米化对材料性能的影响及其机理,上述微观变化对材料疲劳强度、耐腐蚀性、摩擦磨损性能、生物学性能等产生显著影响。总结了各个典型表面纳米化工艺的特点,相比于其他表面纳米化技术,超声振动辅助加工具有不需引入其他元素、不污染环境、原理简单、高速高质量、成本低廉、可依托于各种传统加工工艺等优势,对材料摩擦磨损性能、疲劳性能、生物学性能、表面浸润性和耐腐蚀性等具有积极作用。最后对表面纳米化工艺的未来发展做了展望,其中针对性分析了超声振动辅助加工。针对纳米晶结构表面层的数字化仿真模拟极其匮乏这一现状,将模拟仿真与试验相结合,分析微组织结构与加工参数、微组织结构与材料性能的映射关系并建立模型直观反映尚需更全面系统的研究。材料的某些性能可能不会同时达到最优值,依...     

双熔体混合-快速凝固原位生成TiB2/Cu复合材料的研究

利用双熔体混合-快速凝固的原位反应技术制备了Cu-纳米TiB2复合材料。用XRD、TEM等手段对TiB2/Cu复合材料进行结构分析。研究表明,铜基体中分布着尺寸约40 nm的TiB2颗粒,对Cu基体有良好的增强作用,同时对双熔体混合反应生成TiB2的热力学进行了讨论。     

镀铜碳纳米管对铜基复合薄膜组织及性能的影响

解决碳纳米管团聚问题以及改善碳纳米管与基体材料间界面的结合是提升碳纳米管铜基复合薄膜性能的关键.文中通过对比碳纳米管铜基复合薄膜和镀铜碳纳米管铜基复合薄膜的组织和性能的差异，结合量子隧道效应、DLVO理论以及材料力学相关理论，分析了镀铜碳纳米管对复合薄膜组织及性能的影响.结果表明，未镀铜和镀铜的碳纳米管含量为1.0%(质量分数)时，碳纳米管铜基复合薄膜和镀铜碳纳米管铜基复合薄膜电阻率分别为25.17和17.73μΩ·cm，在不同的弯曲循环次数下的电阻变化率均是前者大于后者.碳纳米管镀铜后，其尺寸和表面结构所发生的改变抑制了团聚，提高了其与铜基体之间的结合强度，进而提升复合薄膜性能.从增强材料对复合材料的组织和性能影响的角度出发，得出了镀铜碳纳米管对铜基复合薄膜组织及性能的影响机理，为后续柔性印刷电子技术的研究提供理论依据.     

纳米SiO2对铜基摩擦材料摩擦学性能的影响

采用粉末冶金法制备添加0.75%的纳米SiO2(n-SiO2)和0.75%Cu包覆纳米SiO2(Cu/n-SiO2)复合粉体的新型铜基摩擦材料.采用惯性台架实验机,研究比较两种材料与未添加纳米SiO2的材料的摩擦学性能.结果表明:在铜基摩擦材料中添加微量n-SiO2可改善材料的耐磨性和耐热性;添加Cu/n-SiO2的铜基摩擦材料,耐热性提高32%,耐磨性提高2.02倍;添加n-SiO2的摩擦材料,耐热性提高7%,耐磨性提高18%;经铜包覆处理后的n-SiO2对材料性能的影响优于未处理的n-SiO2.     

Ti_2AlN-La_2O_3/Cu复合材料的界面反应与性能

采用粉末冶金法制备了以Ti2AlN和La2O3为增强相的新型铜基复合材料。研究了Ti2AlN与Cu界面反应及其对复合材料性能的影响。结果表明:Ti2AlN颗粒化学镀铜后改善了铜与Ti2AlN的界面结合情况,形成了宽度为20 nm左右的过渡区。在880~940℃的烧结温度范围内,增强相与基体的界面发生化学反应,生成了Cu(Al)固溶体与TiNx,在显著提高复合材料强度的同时,降低材料的导电性。另外,La2O3纳米颗粒分布在铜基体内,对材料起到弥散强化的作用。     

激光诱导表面改性制备铜基非晶-纳米晶粉末冶金摩擦材料

为改善铜基粉末冶金摩擦材料的摩擦磨损性能,研究了激光诱导表面改性制备铜基非晶-纳米晶粉末冶金摩擦材料方法.采用扫描电镜、透射电镜、X射线衍射仪及硬度计等对粉末冶金摩擦材料层微观组织及性能进行了表征,结果表明:由于激光的急速加热和冷却以及以小质点杂质形式分布于α-Cu基体中的Zn,Sn和Pb元素抑制了再结晶的形核及长大,导致铜基非晶一纳米晶粉末冶金摩擦材料的形成.同时激光表面改性处理后,α-Cu相的晶粒尺寸减小了35%,二类应变均方根值增大39%,位错密度增加97%.聚合生长状态的α-Cu产生边缘溶解,大体积α-Cu枝解细小化.摩擦材料表观硬度提高了12.7%,α-Cu相显微硬度提高了14%.耐磨性能提高45%,摩擦系数升高1%.     

铜基粉末冶金摩擦材料特征摩擦组元与基体的界面形成及磨损机理

从界面角度出发,研究铜基粉末冶金摩擦材料中不同特征摩擦组元与基体组元形成的界面,并深层次探讨界面与摩擦表面、亚表面结构、摩擦磨损性能及磨损机理之间的关系。结果表明:Si C分别与基体Cu和Fe形成结合较差的机械结合界面和反应结合界面,高碳铬铁(HCC)与基体Cu形成扩散-机械结合界面;Si C与HCC均与基体形成含缺陷界面,而裂纹易沿界面缺陷形核扩展,使材料发生剥层磨损,促进机械混合层(MML)形成。而Si O2与铜基体形成紧密机械结合界面,使得材料表层Si O_2受摩擦力及正压力的反复作用发生破碎剥落,从而导致严重犁削磨损。     

高氮奥氏体不锈钢0Cr21Mn17Mo2NbN0.83表面机械纳米化及其热稳定性研究

对高氮奥氏体不锈钢0Cr21Mn17Mo2Nb N0.83进行表面机械压磨处理,重点研究经360 min表面机械压磨后,高氮奥氏体不锈钢表面纳米层的组织结构和在不同加热温度、保温时间条件下,该纳米表面层的热稳定性。结果表明:高氮奥氏体不锈钢0Cr21Mn17Mo2Nb N0.83经360 min表面机械压磨处理后,表面晶粒尺寸达到纳米级别,表面层的硬度较芯部基体增加一倍以上,且由芯部基体到表面的晶粒逐渐细化;机械压磨以及随后的热处理均未造成高氮奥氏体不锈钢表面层单一奥氏体结构的改变,表明该种材料具有良好的结构稳定性;加热温度对高氮奥氏体不锈钢0Cr21Mn17Mo2NbN0.83表面纳米层及过渡层的组织稳定性起决定作用,而保温时间对其影响不大。     

工业纯铜膏剂法陶瓷/渗铝复合涂层耐磨性研究

采用膏剂法及加热扩散在纯铜表面制备铜基陶瓷/渗铝复合涂层。观察分析了复合涂层的形貌和结构,并研究了该复合涂层的抗热震性能、涂层硬度、耐磨性。结果表明:纯铜膏剂法热化学反应陶瓷/渗铝复合涂层中有Na7Al3O8、Cu3TiO4、Cu9Al4等新相生成;复合涂层在700℃条件下热震次数可达40次以上;复合涂层的硬度可达83.8 HRE,耐磨性实验中,复合陶瓷涂层的相对耐磨性是基体的5.40倍;复合陶瓷涂层的黏着磨损(干摩擦)相对耐磨性是基体的5.64倍;复合陶瓷涂层的黏着磨损(油摩擦)相对耐磨性是基体的10.14倍。     

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.