塑性变形对单晶铜线材导电性影响的研究

为了研究塑性变形对单晶铜线材导电性的影响，以及电阻率与塑性变形量之间的定量关系，将Φ8mm的工业单晶铜线材冷拔后，得到塑性变形量不同的试样，用四端引线法精确测量其电阻率、结果表明，单晶铜线材的电阻率随塑性变形量的增加而上升，其原因是由于单晶铜线材的微观组织畸变程度随塑性变形量的增加而加剧。     

铜包铝废导线中的铜铝工业化分离及回收方法的研究

利用化学方法,使用硝酸、硫酸与双氧水两组反应试剂分另q处理铜包铝废导线,使废导线外层的铜转化为相应的可溶性铜盐,而铝因钝化作用不参与反应或与酸反应速度比较缓慢,从而达到废导线中铜铝分离的目的,提升了废导线的经济价值,实现了贵重资源的再生利用.     

单股铜导线一次短路熔痕过渡区特征影响因素研究

本文对单股铜导线一次短路熔痕过渡区处的晶粒及气孔显微特征进行观察,并利用Image-Pro Plus软件对所得金相图像进行处理分析,并与国家标准（《电气火灾原因技术鉴定方法》GB/16840.1-1997）作比较,从而得出线径、温度对铜导线一次短路熔痕过渡区处晶粒粒径,气孔面积的影响规律。     

各向异性铜双晶晶界应力与晶界形变分析

基于晶体滑移理论和率相关的晶体滑移有限元程序, 对压缩面力作用下的各向异性铜双晶晶界平面处应力场进行了计算, 对晶界附近应力变化与晶粒滑移变形进行了分析;根据梁变形理论, 对垂直晶界的周期性扭曲变形和周期法向应力进行了理论分析和推导说明.结果表明:在晶界处存在较大的应力梯度和应力集中现象, 晶粒的取向对晶界面的应力分布有很大的影响, 晶粒的滑移变形是从部分区域先行开动.     

拉拔变形对纯铜导线组织和性能的影响

初始直径为Φ8 mm的纯铜杆坯经拉拔得到直径为Φ1.8 mm和Φ0.171 mm的铜导线.采用光学金相显微镜、微机控制电子万能实验机和直流低电阻测试仪研究了拉拔过程中纯铜导线微观组织、力学性能和电阻率的变化.结果表明,在拉拔过程中导线微观组织沿拉拔方向逐渐形成纤维组织.抗拉强度和电阻率随着变形程度的增加而增大,直径为Φ8 mm的纯铜杆坯经过单道次拉拔后得到直径为Φ1.8 mm的纯铜导线,抗拉强度由226 MPa增至380 MPa,断后延伸率由45％下降至35％,电阻率由0.0169Ω?mm2?m-1增至0.0172Ω?mm2?m-1.由拉拔过程中的微观组织变化情况得到了微观组织和力学性能之间的关系,即随着纤维状组织的形成,纯铜导线的抗拉强度增加,断后延伸率降低.     

对无定向导线和附合导线的精度分析

对一般无定向导线、闭合无定向导线及附合导线的精度进行了讨论及分析比较,得出闭会无定向导线的精度比一般无定向导线的精度高2倍左右,附合导线比闭合无定向导线的精度高3倍.同时得出,闭合EDM无定向导线是一种很有潜力及值得推荐使用的导线.     

紫杂铜中杂质行为的研究

采用喷射冶金技术，讨论了紫杂铜中杂质总量对铜延伸率和电阻率的影响规律，分析了工艺因素对杂质去除的影响，给出了铜液中杂质去除的速度，确定了铜液中杂质去除的工艺要点，使电工用铜Ｔ２黑杆超过了ＧＢ３９５２－８３ＩＥＣ２８标准。     

过硫酸铵掺杂聚苯硫醚纤维的导电性研究

分别选用过硫酸铵、双氧水、三氯化铁作为掺杂剂,对聚苯硫醚(PPS)纤维进行液相掺杂,并对掺杂后PPS纤维的结构和性能进行表征,探索其导电机理,研究其导电性.结果表明,过硫酸铵作为掺杂剂时效果最好,可使其电导率从10-13S/cm升高到10-7S/cm.     

二氧化铈的电子结构和导电性研究

采用第一性原理赝势平面波方法计算了立方萤石型CeO2的晶体参数.在此基础上,计算了能带结构、总态密度、分波态密度和布居分布,分析了CeO2的的电子结构,研究了其导电性较弱的原因.     

Microstructure evolution of single crystal copper wires in cold drawing

The deformation microstructure evolution of single crystal copper wires produced by OCC method has been studied with the help of TEM, EBSD and OM. The results show that there are a small number of dendrites and twins in the undeformed single crystal copper wires. However, it is difficult to observe these dendrites in deformed single crystal copper wires. The structure evolution of deformed single crystal copper wires during drawing process can be divided into three stages. When the true strain is lower than 0.94, macroscopic subdivision of grains is not evident, and the microscopic evolution of deformed structure is that the cells are formed and elongated in drawn direction. When the true strain is between 0.94 and 1.96, macroscopic subdivision of grains takes place, and the number of microbands located on {111} and cell blocks is much more than that with the true strain lower than 0.94. When the true strain is larger than 1.96, the macroscopic subdivision of grains becomes more evident than that with the true strain between 0.94 and 1.96, and S-bands structure and lamellar boundaries will be formed. From EBSD analysis, it is found that part of 〈100〉 texture resulting from solidifying is transformed into 〈111〉 and 〈112〉 due to shear deformation, but 〈100〉 texture component is still kept in majority. When the true strain is 0.94, the misorientation angle of dislocation boundaries resulting from deformation is lower than 14°. However, when the true strain arrives at 1.96, the misorientation angle of some boundaries will be greater than 50°, and the peak of misorientation angle distribution produced by texture evolution is located in the range between 25° and 30°. Supported by the National Natural Science Foundation of China (Grant Nos. 50471098 and 59971033), the Natural Science Foundation of Shaanxi Province, China (Grant No. 2003E101), and the Teaching and Research Award Program for Outstanding Young Teachers in Higher Education Institution of MOE, China     

晶粒度对多晶铜纳米压痕表面变形机理影响

为研究晶粒度在多晶材料纳米压痕过程中对其塑性变形机制及位错演生过程影响.采用Poisson-Voronoi和Monte Carlo方法建立大规模多晶铜分子动力学模型,针对多晶铜Hall-Petch效应曲线建立具有不同晶粒度的多晶铜模型,并与单晶铜纳米压痕模型对比,采用分子动力学方法模拟计算金刚石探针压入模型的纳米压痕过程,计算4种模型的缺陷结构的配位数、内应力、原子势能等参数.采用中心对称参数法研究压痕过程中位错等缺陷结构的演化机制.结果表明:具有不同晶粒度的多晶铜纳米压痕过程存在显著的规律性,单晶铜压痕力高于多晶铜,多晶铜压痕力随着晶粒度降低而下降;多晶铜的晶界结构能够限制压痕缺陷、内应力与原子势能向材料内部传递,而单晶铜难以限制此传递过程;压痕过程中,具有较小晶粒度的多晶铜具有更高的静水压力、范式等效应力与原子势能,单晶铜内应力与原子势能低于多晶铜.表层及亚表层为较低晶粒度而材料内部为较大晶粒度的梯度晶粒度材料具有极大的研究价值.     

挤压温度对高纯铜组织演变规律的影响

为了研究挤压温度对高纯铜微观组织和变形行为的影响规律,通过反向挤压方式对高纯铜进行不同挤压温度下的挤压实验并观察了其显微组织.结果表明,随着挤压温度的升高,高纯铜的晶粒尺寸增大.当挤压温度为650 ℃时,挤压棒材的平均晶粒尺寸为36 μm;当挤压温度升至800 ℃时,挤压棒材的平均晶粒尺寸为51 μm.随着变形量的增加,当挤压温度为650~700 ℃时,压余变形区的平均晶粒尺寸趋向于由60 μm变为45 μm;当挤压温度为750~800 ℃时,平均晶粒尺寸则趋向于由90 μm变为75 μm.800 ℃挤压变形后晶粒内部出现大量以Σ 3特殊晶界为孪晶界的<111>60°退火孪晶.     

ZA27合金中Y及Fe的晶界偏聚电子理论研究

根据分子动力学理论建立了液态ZA27合金的原子集团，结合计算机编程构造出ZA27合金α相与液相共存时的原子构形及α相大角度重位点阵晶界模型.利用递归法计算了Fe、Y固溶于晶粒内，游离于固液相界面及其在α相晶界处的环境敏感镶嵌能.由此得出：Fe、Y处于固液相界区时比在晶内更稳定，并解释了Fe、Y在α相内溶解度很小，结晶时富集于固液相界前沿液体中，从而导致凝固结束后Fe、Y偏聚于晶界，形成成分复杂的稀土化合物的事实.     

Effects of submicron diamonds on the growth of copper in Cu-diamond co-deposition

Submicron diamonds were co-deposited on aluminum substrates with copper from the acid copper sulfate electrolyte by electrolyte-suspension co-deposition.After submicron diamonds were added to the electrolyte,the shape of copper grains transformed from oval or round to polyhedron,the growth mode of copper grains transformed from columnar growth to gradual change in size,and the preferred orientation of copper grains transformed from (220) to (200).Analyzing the variation of cathodic overpotential,it was found that the cathodic overpotential tended to remain unchanged when copper plane (220) grew in the process of electrodepositing pure copper,while it tended to decrease with time when copper plane (200) grew m the process of co-deposition.It was inferred that copper plane (200) was propitious to the deposition of submicron diamonds.     

Effects of grain size on phase transition behavior of nanocrystalline shape memory alloys

We report recent advances in the experimental and theoretical study of grain size(GS)effects on the thermal and mechanical properties of nanostructured NiTi polycrystalline shape memory alloy(SMA).It is shown that when GS<60 nm,the superelastic stress-strain hysteresis loop area(H)of the polycrystal decreases rapidly with GS and tends to vanish as GS approaches 10 nanometers.At the same time,the temperature dependence of the transition stress also decreases with GS and eventually approaches zero,leading to a wide superelastic temperature window and breakdown of the Clausius-Claperyon relationship.Rate dependence of the stress-strain responses is significantly reduced and the cyclic stability of the material is improved by the nanocrystallization.It is proposed that the emergence of such significant changes in the behavior of the material with GS reduction originate from the large increase in the area-to-volume ratios of the nanometer-thick interfaces(grain boundary and Austenite-Martensite(A-M)interface)in the polycrystal.In particular,with GS reduction,interfacial energy terms will gradually become dominant over the bulk energy of the crystallite,eventually bring fundamental changes in the phase transition responses of the material.Modelling strategy leading to the establishment of quantitative relationships among GS,grain boundary,A-M interfaces and the macroscopic responses of the material are outlined.     

Preparation of copper nano-wires by template synthesis method

Highly ordered and porous anodic aluminum oxide templates were prepared. The ordered copper nanowires arrays were assembled in nano-holes of the template by alternating current electrodeposition at lower voltage.The morphologies of template and copper nano-wires arrays were characterized by means of field emission scanning electron microscope(FESEM) and the crystal structure of copper nano-wires was determined by means of X-ray diffraction. The results indicate that copper nano-wires hold the preferred crystalline orientation along (111), (200),(220) and (331) crystal faces during growth, and the growth of copper nano-wires in the nano-holes of the template is homogenous and continuous.     

Effects of Phosphorus Grain Boundary Segregation and Hardness on the Ductile-to-Brittle Transition for a 2.25CrlMo Steel

The combined effect of phosphorus grain boundary segregation and hardness on the ductile-to-brittle transition was examined for a P-doped 2.25CrlMo steel by using Auger electron spectroscopy in conjunction with hardness measurements, Charpy impact tests and scanning electron microscopy. With prolonging time at 540 ~C after water quenching from 980℃, the segregation of phosphorus increases and the hardness decreases. The DBTT （FATT） increases with increasing phosphorus segregation and decreases with decreasing hardness. The effect of phosphorus segregation is dominant until 100 h aging and after that the hardness effect becomes dominant. This effect makes the DBTT （FATT） decrease with further prolonging ageing time although the segregation of phosphorus still increases strongly.