单晶铜线材载流摩擦磨损行为研究

在经改制过的MS-T3000摩擦磨损试验机上,以黄铜为摩擦副,对热型连铸技术制备的单晶铜进行载流摩擦磨损试验,研究了电流对单晶铜导线载流摩擦磨损行为的影响。结果表明:电流强度对单晶铜干摩擦磨损行为有显著影响。电流在0~15 A范围内,随着电流的增加,摩擦系数与磨损率变化基本一致,呈现先减少后增加的趋势。电流较小时,接触电阻也比较小且较稳定;电流高时,接触电阻比较大,波动剧烈,而且有电弧出现。单晶铜导线在带电条件下的主要磨损形式为磨粒磨损、粘着磨损以及以电化学作用为主的氧化磨损或腐蚀磨损。     

动载荷条件下紫铜／铬青铜受流摩擦磨损性能

以紫铜/铬青铜摩擦副为研究对象模拟受电弓与导线的服役条件,在HST100型销盘式高速载流试验机上考察了该材料在动载荷(按正弦规律加载)条件下受流摩擦磨损性能.结果表明:在动载荷条件下,电流是影响其摩擦磨损性能的重要因素.摩擦系数、磨损率均随电流的增大递增,但随着电流的进一步增加其增大趋势减缓;粘着磨损、电弧侵蚀、塑性变形是其主要的磨损形式.     

Cu-Cr合金电滑动摩擦磨损性能研究

对制备的Cu-Cr析出强化型铜合金在电磨损试验机上进行磨损试验,并用扫描电子显微镜观察材料的磨损表面形貌,用能谱仪对其磨损表面主要元素进行分析,然后探讨其磨损机制.结果表明,Cu-Cr合金的磨损率随滑行距离的增加而增加;磨损率随Cr含量的增加而减小,其中Cu-0.65Cr、Cu-0.76Cr合金的磨损率是Cu-0.86Cr合金磨损率的2～3倍;Cu-Cr合金的磨损机制以粘着磨损为主.     

高强高导Cu-Cr-Ag-Y合金的时效特征及其载流滑动磨损性能

对经过连续铸造、固溶和冷拉拔的Cu-Cr-Ag-Y合金进行时效处理,研究了时效工艺参数对合金组织和性能的影响,探讨了合金的时效特征,并在自制磨损试验机上对合金线材进行载流滑动磨损试验。结果表明:铜基体中球形第二相的均匀析出是合金综合性能提高的根本原因。Cu-0.6Cr-0.15Ag-0.03Y合金经450℃/4 h时效处理后可以获得较好的综合性能,其显微硬度与导电率达到245Hv和80.7%IACS。随着加载电流的增加,合金磨损量变大,其载流磨损机制为电侵蚀磨损、磨粒磨损和粘着磨损。     

Cu-Ag-Cr-Ce合金材料载流磨损行为的研究

用真空熔炼法制备了Cu-Ag-Cr-Ce合金,借助于载流磨损试验机对该合金的载流磨损行为进行了研究,利用扫描电镜对该合金载流磨损后线材表面的组织形貌进行观察.结果表明:Cu-Ag-Cr-Ce合金的磨损率随滑行距离和受电电流的增大而增大;其载流磨损的主要磨损机制为粘着磨损、磨粒磨损和电侵蚀磨损:在相同的载流磨损试验条件下,Cu-Ag-Cr-Ce合金材料的耐磨性优于Cu-Ag、Cu-Ag-Cr合金材料.     

载流条件下铜-石墨复合材料摩擦学性能研究

在载流高速摩擦磨损试验机上进行试验,研究了不同电流和速度对铜-石墨复合材料摩擦系数和磨损率的影响,并对摩擦表面的形貌进行了观察和分析。结果表明:电流、速度是影响铜-石墨复合材料载流摩擦磨损性能的重要因素。在速度一定的条件下,随着电流增大,铜-石墨复合材料的摩擦系数减小,磨损率增大;在电流一定的条件下,材料的摩擦系数随速度的增大先升高后降低,磨损率随速度的增大先升高后降低,然后迅速增大,在速度为40 m/s时,材料的磨损机制出现了明显的变化。     

内氧化法制备Al2O3/Cu复合材料的载流摩擦磨损特性

采用内氧化法制备了Al2O3／Cu复合材料，研究了复合材料在载流条件下的摩擦磨损特性，并进行了微观组织结构分析。结果表明：采用内氧化法制备的Al2O3／Cu复合材料，在铜基体中弥散分布着纳米级的Al2O3颗粒；载流条件下，该复合材料的抗摩擦磨损性能显著优于铬青铜合金；电流较小时具有磨粒磨损和粘着磨损的共同特征，电流较大时以粘着磨损为主。在试验范围内，电流比载荷对磨损率的影响显著。     

铜基粉末冶金材料载流摩擦学特性研究

以铜基粉末冶金材料/铬青铜为摩擦副,模拟电力机车接触网中受电弓滑板和导线的服役条件,在销-盘式摩擦磨损试验机上进行了载流摩擦学特性研究。研究表明,随着电流的增大,摩擦系数呈下降趋势,磨损率呈上升趋势。试验较低电流（40A和60A）条件下,摩擦表面形成一氧化层;试验较高电流（80A和100A）条件下,摩擦表面覆盖有熔融物。载流条件下,销试样材料表面不断发生氧化,较低电流时,摩擦表面覆盖着一层Fe的氧化物;较高电流时,试样由于表面温度更高,形成Cu的氧化物。     

电流和摩擦速度对输电材料磨损性能的影响

在载流高速摩擦磨损试验机上进行磨损试验,研究了速度和电流对输电材料(纯铜)磨损性能的影响,并对摩擦表面形貌进行了观察。结果表明:在一定速度条件下,电流增大,纯铜的摩擦系数减小,磨损率增大;在一定电流条件下,速度增大,纯铜的摩擦系数和磨损率都增大;在电流和速度的影响下,摩擦表面呈现粘着、塑性变形及氧化磨损特征。     

碳纤维增强Ag-MoS2复合材料的摩擦磨损性能

采用MoS2、碳纤维(CF)及特种碳纤维(SCF)作为润滑相,制备3种固体润滑复合材料(Ag-2.5Cu-8MoS2、Ag-2.5Cu-8MoS2-3CF、Ag-2.5Cu-8MoS2-3SCF),对所得材料进行系统的摩擦磨损性能测试,重点关注各润滑相对材料摩擦磨损性能的影响规律。结果表明:独立采用MoS2作为润滑相时可使材料获得较好的摩擦磨损性能和较低的摩擦因数,其磨损率为24×10 14m3/(N.m),摩擦因数为0.122;添加碳纤维能提高材料的耐磨性能,其中添加特种碳纤维所得材料Ag-2.5Cu-8MoS2-3SCF的磨损率最低(4.08×10 14m3/(N.m)),其耐磨性能比Ag-2.5Cu-8MoS2的提高了6倍,但添加碳纤维显著增加了材料的摩擦因数,测试过程发现加入碳纤维后材料的摩擦因数由0.122分别升至0.154(CF)和0.167(SCF)。由于特种碳纤维材料较高的硬度(319.369 HV)和较好的耐磨性以及MoS2较好的润滑性能,采用特种碳纤维和MoS2对银基材料进行复相润滑可使材料获得较好的综合摩擦磨损性能。     

Effects of Post-weld Heat Treatment on Microstructure,Mechanical Properties and the Role of Weld Reinforcement in 2219 Aluminum Alloy TIG-Welded Joints

In as-welded state, each region of 2219 aluminum alloy TIG-welded joint shows diff erent microstructure and microhardness due to the diff erent welding heat cycles and the resulting evolution of second phases. After the post-weld heat treatment, both the amount and the size of the eutectic structure or θ phases decreased. Correspondingly, both the Cu content in α-Al matrix and the microhardness increased to a similar level in each region of the joint, and the tensile strength of the entire joint was greatly improved. Post-weld heat treatment played the role of solid solution strengthening and aging strengthening. After the post-weld heat treatment, the weld performance became similar to other regions, but weld reinforcements lost their reinforcing eff ect on the weld and their existence was more of an adverse eff ect. The joint without weld reinforcements after the post-weld heat treatment had the optimal tensile properties, and the specimens randomly crack in the weld zone.     

The First Phase of the SRIF Industrialized Base in ＂West Area＂ Has Been Put into Operation

After nearly two years＇ tense construction, the first phase of industrialized base of Shenyang Research Institute of Foundry （SRIF）, located at the Tiexi Casting and Forging Industrial Park in the west of Tiexi District, has now been completed and formally put into operation.     

THERMODYNAMICS STUDY ON THE DECOMPOSITION OF CHROMITE WITH KOH

Institute of Process Engineering, Chinese Academy of Sciences, China, has proposed a method for oxidative leaching of chromite with potassium hydroxide. Understanding the mechanism of chromite decomposition, especially in the potassium hydroxide fusion, is important for the optimization of the operating parameters of the oxidative leaching process. A traditional thermodynamic method is proposed and the thermal decomposition and the reaction decomposition during the oxidative leaching of chromite with KOH and oxygen is discussed, which suggests that chromite is mainly destroyed by reactions with KOH and oxygen. Meanwhile, equilibrium of the main reactions of the above process was calculated at different temperatures and oxygen partial pressures. The stable zones of productions, namely, K2CrO4 and Fe2O3, increase with the decrease of temperature, which indicates that higher temperature is not beneficial to thermodynamic reactions. In addition, a comparison of the general alkali methods is carried out, and it is concluded that the KOH leaching process is thermodynamically superior to the conventional chromate production process.     

INFLUENCE OF HEAT TREATMENT ON DAMPING BEHAVIOUR OF THE MAGNESIUM WROUGHT ALLOY AZ61

The effect of isochronal heat treatments for 1h on variation of damping, hardness and microstructural change of the magnesium wrought alloy AZ61 was investigated. Damping and hardness behaviour could be attributed to the evolution of precipitation process. The influence of precipitation on damping behaviour was explained in the framework of the dislocation string model of Granato and Lücke.     

Theoretical Analysis for the Motion and Temperature of Melt Droplets in Spray Degassing Process

The motion of melt droplets in spray degassing process was analyzed theoretically. The height of the treatment tank in spray degassing process could be determined by the results of theoretical calculation of motion of melt droplets. To know whether the melt droplets would solidify during spraying process, the balance temperature of melt droplets was also theoretically analyzed. Then proof experiments for theoretical results about temperature of melt droplets were carried. In comparison, the experimental results were nearly similar to the calculation results.     

Growth Kinetics of Single Inclusion Particle in Molten Melts

On the basis of the single-particle framework, a new theory on inclusion growth in metallurgical melts is developed to study the kinetics of inclusion growth on account of reaction and collision. The studies show that the early growth of inclusion depends on reaction growth and Brawnian motion collision, and where the former is decisive, the late growth depends on turbulence collision and Stokes＇ collision, and where the former is dominant; collision growth is very quick during the smelting process, lessened in the refining process, but nearly negligible in the continuous casting process.     

An Easy Way to Quantify the Adhesion Energy of Nanostructured Cu/X(X=Cr,Ta,Mo,Nb,Zr) Multilayer Films Adherent to Polyimide Substrates

An approach based on film buckling under simple uniaxial tensile testing was utilized in this paper to quantitatively estimate the interfacial energy of the nanostructured multilayer films(NMFs) adherent to flexible substrates. The interfacial energies of polyimide-supported NMFs are determined to be *5.0 J/m2 for Cu/Cr, *4.1 J/m2 for Cu/Ta,*2.8 J/m2 for Cu/Mo, *1.1 J/m2 for Cu/Nb, and *1.2 J/m2 for Cu/Zr NMFs. Furthermore, a linear relationship between the adhesion energy and the interfacial shear strength is clearly demonstrated for the Cu-based NMFs, which is highly indicative of the applicability and reliability of the modified models.     

High-Speed Friction Stir Welding of SiC_p/Al–Mg–Si–Cu Composite

A 17 vol% SiCp/Al–Mg–Si–Cu composite plate with a thickness of 3 mm was successfully friction stir welded(FSWed) at a very high welding speed of 2000 mm/min for the first time. Microstructural observation indicated that the coarsening of the precipitates was greatly inhibited in the heat-affected zone of the FSW joint at high welding speed, due to the significantly reduced peak temperature and duration at high temperature. Therefore, prominent enhancement of the hardness was achieved at the lowest hardness zone of the FSW joint at this high welding speed, which was similar to that of the nugget zone. Furthermore, the ultimate tensile strength of the joint was as high as 369 MPa, which was much higher than that obtained at low welding speed of 100 mm/min(298 MPa). This study provides an effective method to weld aluminum matrix composite with superior quality and high welding efficiency.     

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。     

A STUDY OF TEMPERATURE-DEPENDENT VALENCE BOND STRUCTURE OF TITANIUM

On the basis of energy and shape method for the determination of the valence bond (VB) structures of crystal, the valence bond structure of titanium is redetermined at room temperature and calculated in the whole temperature range of 0-1943K. The outer shell electronic distribution of Ti is e_c~(2.9907) · (s_c~(0.4980) d_c~(2.4927)) ef1.0093 in crystal. The temperature dependences of the VB structures of hcp and bcc phases are the same. The VB structures of hcp and bcc phases monotonically increase or decrease with the increase in temperature, but show discontinuous changes at the phase-transformation temperature 1155K.