微量稀土对铸态Cu-3.0Si-2.0Ni合金组织及性能的影响

加入适量的稀土元素能有效改善铜合金的组织和性能.铸态Cu-3.0Si-2.0Ni合金中添加稀土Ce后,进行熔炼及热处理试验,再通过室温拉伸、导电率试验和金相观察,研究了微量Ce对铸态Cu-3.0Si-2.0Ni合金组织与性能的影响.结果表明:铸态合金晶粒随着Ce含量的升高呈现先减小后递增的趋势;铸态合金的抗拉强度和导电性随着Ce的增加分别先升高后减低;当Ce的质量分数为0.06%时,铸态合金的抗拉强度最高、导电性最强.     

稀土Ce对锌电积用Pb-Ag-Ca-Sr四元合金阳极板性能的改进

Pb-Ag-Ca-Sr四元合金具有较好的力学性能、导电性能和耐腐蚀性能,但合金元素分布不均、性能不稳定、稀贵金属损耗大、制作成本高,制约其在湿法炼锌电积阳极的广泛应用。通过熔炼工艺向Pb-Ag-Ca-Sr四元合金中添加稀土Ce,然后进行轧制,分别考察稀土Ce对Pb-Ag-Ca-Sr四元合金显微组织、力学性能、导电性和耐腐蚀性能的影响。结果表明,添加质量分数为0.04%的稀土Ce后,Pb-Ag-Ca-Sr四元合金的晶粒明显得到细化,抗拉强度、屈服强度和电导率分别提高9%、23%和1.75%,耐腐蚀性能也得到明显提高,稀土Ce对Pb-Ag-Ca-Sr四元合金阳极材料综合性能提升作用强于轧制工艺。     

微量稀土钇对Cu-Cr-Zr合金时效性能的影响

研究了微量稀土钇对Cu-Cr-Zr合金时效后导电率和显微硬度的影响。结果表明:Cu-0.41Cr-0.10Zr合金在950℃固溶1 h后,在480℃时效2h能获得较高的显微硬度和导电率;时效前冷变形可加快第二相的析出,使其性能得到显著提高。固溶后经60%变形后于480℃时效1 h其显微硬度和导电率分别高达154.3HV和81.5%IACS,而固溶后直接时效时仅为110.2HV和65.2%IACS。微量稀土元素Y的加入,使Cu-0.39Cr-0.11Zr-0.041Y合金的显微硬度较Cu-0.41Cr-0.10Zr合金高9HV,而导电率略有降低。     

Influence of cold rolling and annealing on the microstructure,mechanical properties,and electrical conductivity of an artificial microcomposite Cu-18% Nb alloy

The influence of cold rolling and subsequent annealing at different temperatures on the micro-structure, strength properties, and electrical conductivity of a microcomposite Cu-18% Nb alloy fabricated by bundling and deformation is studied. A composite billet is rolled up to a total true strain of 3.5 and 5.1. After rolling, a nanocrystalline structure is obtained with an average filament width of 70–100 nm depending on the rolling strain. The ultimate tensile strength of the rolled foils is 867–934 MPa and the electrical conductivity is 19–40% of the pure copper conductivity. It is shown that annealing at 550°C results in an increase in the conductivity from 40 to 60% at a retained strength (microhardness) of the alloy.     

Strength and conductivity of Cu-9Fe-1.2X (X = Ag or Cr) filamentary microcomposite wires

In this study, strength and electrical conductivity of Cu-9Fe-1.2X (X = Ag or Cr) microcomposite wires obtained by cold drawing combined with intermediate heat treatments have been investigated. During cold working, the primary and secondary dendrite arms are aligned along the drawing direction and elongated into filaments. The addition of Ag was found to reduce the filament spacings at the given draw ratio throughout the drawing processing. The ultimate tensile strength and the conductivity of the Cu-Fe-Ag microcomposites were higher than those of Cu-Fe-Cr microcomposites, suggesting the refinement of the filaments is more effective than the strengthening of the filaments in strengthening the microcomposites. The strength of Cu-Fe-Xi microcomposites is dependent on the spacing of the Fe filaments in accord with a Hall-Petch relationship. The fracture surfaces of all the specimens showed ductile-type fracture and iron filaments occasionally observed on the fracture surfaces. The good mechanical and electrical properties in Cu-Fe-Ag wires may be associated with the more uniform distribution of the filaments than in Cu-Fe-Cr wires. The increase of the conductivity in Cu-Fe-Ag and Cu-Fe-Cr after intermediate heat treatments is attributed to the precipitation of Fe, Cr, or Ag particles, which dissolved during heavy deformation processing.     

Strength and electrical conductivity of a deformation-processed Cu-5 Pct Nb composite

A Cu-5 pct Nb alloy was deformation processed by wire drawing to very large reductions (99.9993 pct) and the strength and electrical conductivity properties compared with similarly deformation processed Cu-20 pct Nb. The results showed that the Cu-5 pct Nb alloy was transformed into a composite material with the original Nb dendrites becoming ribbonlike filaments in a similar fashion to higher Nb-containing Cu-Nb alloys. The degree of strength increase with increasing deformation processing greatly exceeds rule-of-mixtures expectations at higher degrees of deformation processing, where the Nb becomes highly aligned with the wire axis. A 5 pct Nb addition appears to contain close to the minimum amount of Nb phase necessary to produce appreciable strengthening during deformation processing of Cu-Nb alloys. The strength-conductivity properties of the deformation-processed Cu-5 pct Nb alloy show significant improvements in strength over the best commercial alloys in the conductivity range of 80 to 90 pct international annealed copper standard (IACS). This article is based on a presentation made in the symposium “High Performance Copper-Base Materials” as part of the 1991 TMS Annual Meeting, February 17–21, 1991, New Orleans, LA, under the auspices of the TMS Structural Materials Committee.     

Cu-20%Ag合金冷拉拔变形过程导电特性研究

通过定向凝固+冷拉拔变形工艺制备了不同线径的Cu-20%Ag（质量分数）合金微细丝线材。通过扫描电子显微镜（SEM）观察了不同线径的Cu-20%Ag合金线材的微观组织演变,发现在拉拔变形过程中, Cu-20%Ag合金线材内部晶粒不断细化,共晶区域较之铜基体区域更为明显,当真应变为 8.13 时线材内部的共晶纤维细化至平均宽度 500 nm 左右。研究了 Cu-20%Ag 合金冷拉拔变形过程中组织性能的演变规律,探明了其组织演变对导电率变化的影响机理。Cu-20%Ag合金在拉拔变形过程中晶粒的细化和破碎导致的晶界面积增加是导电率降低的主要原因。     

铜铬系合金研究和发展现状

铜及铜合金材料广泛应用于电子信息、电气控制、电力传输及轨道交通等领域,随着科技进步和社会发展,对高强度、高导电同时兼备耐热、耐蚀、抗应力松弛等高性能铜合金材料的需求十分迫切。目前,铜铬系合金被认为是综合性能最优异的铜合金之一。本文简要回顾了铜铬系合金的发展历史,总结了其应用现状,重点探讨了稀土元素以及Hf, Ag, Ti, In, Mg, Zr和Sn的添加对铜铬系合金组织及性能的影响规律,并按照单一元素添加、复合元素添加、稀土元素添加的方式,分别讨论了稀土元素以及Ti, Mg, Mg与Si, Ni与Si等对铜铬锆合金组织和性能的影响。通过对文献的整理发现,微量合金元素的添加可明显改善铜铬合金强度与导电匹配性,并提高合金抗软化温度。此外,添加多元微量元素对性能的提升要优于单一元素,若匹配以合适的变形加工和热处理工艺,更易获得理想材料。今后,可以在铜铬锆合金基础上添加稀土元素,找到适宜的添加量以达到在最大化提高强度与抗软化温度的同时最小化影响其导电率。     

Microstructure and properties of as-cast Cu-Cr-Zr alloys with lanthanum addition

Cu-0.45Cr-0.2Zr-xLa (x = 0–0.48) alloys were prepared by vacuum casting. The effects of La addition and orientation on the microstructure and properties of the as-cast alloy were investigated by an optical microscope, a scanning electron microscope with an energy dispersive X-ray spectrometer, a tensile testing machine and an electrical conductivity tester. The result shows that the addition of La significantly refines the columnar grainsize and decreases the secondary dendrite arm spacing. Trace addition of La improves the room temperature ultimate tensile strength, elongation and electrical conductivity mainly by purifying during melting and casting. The ultimate tensile strength, elongation and electrical conductivity significantly decrease with the increase of La content due to formation of coarse particles and oxides, which severely harm the performance of the Cu-0.45Cr-0.2Zr-xLa alloys. The Cu-0.45Cr-0.2Zr-0.13La alloy possesses a good combination of room temperature ultimate tensile strength, elongation and electrical conductivity. In addition, room temperature ultimate tensile strength and electrical conductivity along transverse direction of the ingot are higher than that along longitudinal direction, which is mainly ascribed to different distribution of grain boundary and grain orientation.     

Effect of Cerium on Mechanical Performance and Electrical Conductivity of Aluminum Rod for Electrical Purpose

The effect of rare earth element Ce on mechanical performance and electrical conductivity of aluminum rod for electrical purpose were studied under industrial production condition. Using optical microscope, SEM, TEM, EDS and X-ray diffractometer, the microstructure and phase composition of aluminum rod were measured and analyzed. The results indicate that the content of rare earth element Ce is between 0.05%～0.16% in the aluminum rod for electrical purpose. Its tensile strength is enhanced to some extent. The research also discovers that the tensile strength is enhanced remarkably with impurity element Si content increases. Because influence of Si is big to the conductivity, the Si content should be controlled continuously strictly in the aluminum for electrical purpose. Adding rare earth element Ce reduces the solid solubility of Si in the aluminum matrix, and the negative effect of Si on the aluminum conductor reduces effectively. So the limit of in Si content in aluminum rod for electrical purpose can be relaxed moderately.     

Microstructural size effects in high-strength high-conductivity Cu-Cr-Nb alloys

Microstructural refinement to further improve the strength and stability of high-strength high-conductivity Cu-Cr-Nb alloys was attained by mechanical milling (MM). Mechanically milled Cu-4Cr-2Nb and Cu-8Cr-2Nb exhibited an increase in hot-pressed Vickers hardness of 122 and 96 pct, respectively. Mechanical milling produced a corresponding decrease in electrical conductivity of ∼33 pct for both alloys. The increase in hardness was more due to Cu grain-size refinement than to second-phase particle-size refinement. The drop in conductivity was due to second-phase particle-size refinement, which both increased particle/matrix interfacial area and solute solubility. Mechanically processed Cu-4Cr-2Nb displayed an enhanced thermal stability. Hot-pressed 4-hour milled Cu-4Cr-2Nb experienced a 30 pct increase in conductivity with only a 22 pct drop in hardness when annealed at 1273 K for 50 hours. Such changes were largely due to an increase in dispersed-particle size (i.e., a decrease in solute and interfacial electron scattering) and Cu grain size (reduced Hall-Petch effect), respectively. The optimum hardness and conductivity combination was found in 4-hour milled and hot-pressed Cu-4Cr-2Nb material.     

Effect of Boron and Cerium on Microstructures and Properties of Cu-Fe-P Alloy

The effects of B and Ce on the removal of inclusions, microstructures, and properties of Cu-Fe-P alloys were studied. Certain impurity elements and the microstructures, mechanical properties, and conductivity of four experimental alloys, Cu-0.22Fe-0.06P, Cu-0.22Fe-0.06P-0.05Ce, Cu-0.22Fe-0.06P-0.02B, and Cu-0.22Fe-0.06P-0.05Ce-0. 02B （ %, mass fraction）, were tested and analyzed. Results show that on one hand, B and Ce have a remarkable function of removing S, Pb, and Bi from copper alloys ; on the other hand, the recrystallization temperature of the Cu-Fe-P alloy is considerably increased by adding trace B and Ce, resulting in the combined strengthening effect of precipitation hardening and cold work hardening after cold working and aging, while the negative effect of B and Ce on conductivity is slight. Therefore, a good combination of high strength and conductivity is achieved.     

Cu-Ni-Si-Zr合金时效行为的研究

用扫描电镜（SEM）、涡流电导率测量仪和万能试验机分别对经冷变形后在400～500℃不同时间时效条件下Cu-2.1Ni-0.5Si-0.2Zr合金抗拉强度及电导率性能进行测量,用光学显微镜（OM）、扫描电子显微镜（SEM）观察了合金时效下的组织.结果表明：时效初期合金的抗拉强度及电导率增加较快,随着时效时间的延长,其抗拉强度达到峰值而电导率继续增加.合金在450℃时效2 h,其抗拉强度达到峰值,其值为665 MPa.合金中主要析出相为Ni2Si和CuxZr.利用Mott-Nabarro和Orowan公式对合金强化机理进行了分析.     

均匀化工艺对稀土铝合金电工圆杆组织和性能的影响

采用拉伸力学性能测试、导电率测试、金相显微镜、扫描电镜(SEM)、能谱分析(EDS)以及X射线衍射仪(XRD)等手段,研究了稀土铝合金电工圆杆的组织和性能随均匀化工艺改变而发生的变化。结果表明,均匀化处理可达到细化晶粒、均匀试样组织,净化晶界的效果。与单级均匀化相比,双级均匀化可以使枝晶间未溶物显著减少,且第二相较均匀弥散地分布在基体中。试样在410℃保温2小时后升至425℃继续保温1小时,将获得较佳的综合性能:抗拉强度102 MPa,导电率57.96%IACS;对该试样进行形变量为83%的轧制处理后,强度升高至178 MPa,导电率有所降低,为57.06%IACS。     

Effect of rare earths on viscosity and thermal expansion of soda-lime-silicate glass

Viscosity of soda-lime-silicate glass doped with rare earth oxides(Pr6O11,Eu2O3,Yb2O3) was investigated by the rotating crucible viscometer,the melting temperature and activation energy for viscous flow of the studied melt were derived on the basis of the Arrhenius Equation,the coefficient of thermal expansion,glass transition temperature and dilatometric softening temperature were also determined with dilatometry,in order to reveal the effects of rare earth elements on the behavior of soda-lime-silicate glass.The results showed that introduction of rare earth oxides decreased the viscosity of soda-lime-silicate glass and melting temperature of corresponding melt,increased coefficient of thermal expansion of soda-lime-silicate glass.The glass transition temperature,dilatometric softening temperature,and melting temperature of soda-lime-silicate glass doped with rare earth oxides increased with increasing cationic field strength of corresponding rare earth ions.     

Application of Lanthanum in High Strength and High

China is quite poor in argent resource. Roughly 80% of this industrial argent is imported every year. In order to improve the situation, we took advantage of rare earth (RE) mineral resource and successfully developed the non-argent Lanthanum-tellurium-copper alloy as a substitute for industry argent-copper. In our research, we were able to successfully apply rare earth lanthanum to copper alloy. The defects as porosity, inclusion, etc. originating from nonvacuum melting processing were controlled. Fine grain was obtained. Meanwhile, the comprehensive properties of the copper alloy, such as strength, conductivity and thermal conductivity were improved. The research results in increasing conductivity and thermal conductivity by 5% and 15%, respectively, while the tensile strength is increased by 6% higher than Ag-Cu alloy. The anti-electric corrosion property is good, and there is no argent-cadmium steam population originating from the electric arc effect. The addition of lanthanum further reduces the content of oxygen and hydrogen.The optimum quantity of the addition of RE lanthanum in the copper alloy is 0.010%～0.020%.     

Formation and capturing of nanoparticles in Cu-1 wt.%Fe alloy melt during directional solidification process

A single crystal Cu-1wt.%Fe alloy with finely dispersed iron-rich nanoparticles which keep coherent interface with the copper matrix was prepared under directional solidification.Formation of nanoparticles in the alloy melt was investigated by performing differential scanning calorimeter tests and designed water quenching experiment at a certain temperature.Results show that iron-rich nanoparticles are formed in the Cu-1wt.%Fe alloy melt before primaryα-Cu forms,which is not consistent with equilibrium phase diagram.Mechanism that iron-rich nanoparticles are uniformly captured in the matrix was described,which is that numerous nanoparticles follow Brownian motions and are engulfed in the solidified matrix which makes it possible to form uniformly distributed nanoparticles reinforced single crystal Cu-1wt.%Fe alloy.     

Mechanical Properties and Fracture Behavior of Cu-Co-Be Alloy after Plastic Deformation and Heat Treatment

Mechanical properties and fracture behavior of Cu-0.84Co-0.23 Be alloy after plastic deformation and heat treatment were comparatively investigated.Severe plastic deformation by hot extrusion and cold drawing was adopted to induce large plastic strain of Cu-0.84Co-0.23 Be alloy.The tensile strength and elongation are up to 476.6 MPa and 18%,respectively.The fractured surface consists of deep dimples and micro-voids.Due to the formation of supersaturated solid solution on the Cu matrix by solution treatment at 950℃for 1h,the tensile strength decreased to271.9 MPa,while the elongation increased to 42%.The fracture morphology is parabolic dimple.Furthermore,the tensile strength increased significantly to 580.2 MPa after aging at 480℃ for 4h.During the aging process,a large number of precipitates formed and distributed on the Cu matrix.The fracture feature of aged specimens with low elongation(4.6%) exhibits an obvious brittle intergranular fracture.It is confirmed that the mechanical properties and fracture behavior are dominated by the microstructure characteristics of Cu-0.84Co-0.23 Be alloy after plastic deformation and heat treatment.In addition,the fracture behavior at 450 ℃ of aged Cu-0.84Co-0.23 Be alloy was also studied.The tensile strength and elongation are 383.6 MPa and 11.2%,respectively.The fractured morphologies are mainly candy-shaped with partial parabolic dimples and equiaxed dimples.The fracture mode is multi-mixed mechanism that brittle intergranular fracture plays a dominant role and ductile fracture is secondary.     

电场活化烧结制备Cu-10Cr-0.5Al_2O_3复合材料

对Cu-10Cr-0.5Al2O3(质量分数,%)混合粉末及球磨复合粉末,采用电场活化烧结技术制备高强高导电铜基块体材料,并研究脉冲峰值电流和通电烧结时间对烧结材料组织和性能的影响。结果表明,随着脉冲峰值电流增大,烧结材料的相对密度和导电率均提高,相对密度最高可达99%,硬度和抗弯强度则先上升后下降。当脉冲电流峰值为2.94 kA时,烧结材料具有较好的综合性能,相对密度、硬度、抗弯强度和电导率分别为97.5%、285HV、911MPa和50IACS%;随着通电烧结时间延长,烧结材料的密度、硬度、抗弯强度和导电率均逐渐上升,但烧结时间过长会引起硬度轻微下降;对Cu-10Cr-0.5Al2O3混合粉末进行球磨虽导致烧结材料的电导率下降,但可显著提高材料的硬度和抗弯强度。     

Effect of processing and heat treatment on behavior of Cu-Cr-Zr alloys to railway contact wire

A new series of Cu-Cr-Zr alloys to be used as railway contact wire, Cu-0.26 wt pct Cr-0.15 wt pct Zr, Cu-0.13 wt pct Cr-0.41 wt pct Zr, and Cu-0.34 wt pct Cr-0.41 wt pct Zr, were studied. The results indicated that processing and aging treatment had an effect on the microstructure, tensile strength, and electrical conductivity behavior of the Cu-Cr-Zr alloys. Process I (solution treatment + cold work + aging) was superior to process II (cold work + solution treatment + aging), because precipitation can occur heterogeneously at the dislocations and subcells. An appropriate processing and aging treatment may improve the properties of the alloys due to the formation of fine, dispersive, and coherent precipitates within the matrix. It is demonstrated that the best combination of tensile strength and electrical conducitivity, on the order of 599 MPa and 82 pct IACS (International Annealed Copper Standard), respectively, can be obtained in alloy Cu-0.34 wt pct Cr-0.41 wt pct Zr in the solution-heat-treated, cold-worked, and aged condition. The mechanism of tensile and conductive properties of Cu-Cr-Zr alloy is also discussed.