Temperature dependence of microstructure and texture in cold drawn aluminum wire

The effect of strain and drawing temperature on the evolution of microstructure and fiber textures of aluminum wiresdrawn at room temperature and cryogenic temperature was investigated by TEM and EBSD observations.The results show that lowangle boundaries frequency increases and high angle boundaries frequency decreases with strain increasing when the strain is low.Athigh strain,most of grain and dislocation boundaries are parallel to the drawn direction and low angle boundaries frequencydecreases and high angle boundaries frequency increases with strain increasing.The decrease of deformation temperature leads tomicrostructure finer and low angle boundaries frequency increasing.Texture analysis indicates that volume fraction of complextexture component decreases with strain increasing and a mixture of?111?and?100?fiber texture forms at high strain.?111?is stableat low strains but?100?becomes stable at high strain.The decrease of temperature can enhance the stability of?111?orientation athigh strain.

EFFECT OF RARE EARTH ON CONDUCTANCE OF ALUMINUM WIRE

Effects of Rare Earth(Hereafter RE)on the conductance of high-purity and industrial-purity aluminum wires have been studied.RE increases the resistivity of the high-purity aluminum.No evidence has been found that RE will decrease the resistivity of industrial-pure aluminum under various RE content including 0.3%Ce.The individual role of RE and its combined effects with Fe and Si have been discussed too.

Effect of stress profile on microstructure evolution of cold-drawn commercially pure aluminum wire analyzed by finite element simulation

The evolution of microstructure in the drawing process of commercially pure aluminum wire （CPAW） does not only depend on the nature of materials, but also on the stress profile. In this study, the effect of stress profile on the texture evolution of the CPAW was systematically investigated by combining the numerical simulation and the microstructure observation. The results show that the tensile stress at the wire center promotes the formation of 〈111〉 texture, whereas the shear stress nearby the rim makes little contribution to the texture formation. Therefore, the 〈111 〉 texture at the wire center is stronger than that in the surface layer, which also results in a higher microhardness at the center of the CPAW under axial loading.2017 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science ＆ Technology.

A nanoparticle formation model considering layered motion based on an electrical explosion experiment with AI wires

To study the evolution of nanoparticles during Al wire electrical explosion,a nanoparticle formation model that considered layered motion was developed,and an experimental system was set up to carry out electrical explosion experiments using 0.1 mm and 0.2 mm Al wires.The characteristic parameters and evolution process during the formation of nanoparticles were calculated and analyzed.The results show that the maximum velocities of the innermost and outermost layers are about 1200 m·s-1and 1600 m·s-1,and the velocity of the middle layer is about 1400 m·s-1,respectively.Most of the nanoparticles are formed in the temperature range of2600 K-2500 K.The characteristic temperature for the formation of Al nanoparticles is~2520K,which is also the characteristic temperature of other parameters.The size distribution range of the formed nanoparticles is 18 to 110 nm,and most of them are around 22 nm.The variation of saturated vapor pressure determines the temperature distribution range of particle nucleation.There is a minimum critical diameter of particles(~25 nm);particles smaller than the critical diameter can grow into larger particles during surface growth.Particle motion has an effect on the surface growth and aggregation process of particles,and also on the distribution area of larger-diameter particles.The simulation results are in good agreement with the experiments.We provide a method to estimate the size and distribution of nanoparticles,which is of great significance to understand the formation process of particles during the evolution of wire electrical explosion.

The Largest Copper, Aluminum Wire and Cable Production Enterprise in the Northwestern Region Lands in Qinghai

The largest wire and cable production enterprise in the northwestern region-Qinghai Xingming Electric Power Material Co.,Ltd.has been officially put into production,meaning that Qinghai will be able to selfproduce medium and high voltage or even EHV crosslinked power cables and develop and produce differentiated new products such as high-altitude cold-resistant photovoltaic

A STUDY OF CONTINUOUS EXTRUSION-CLADDING PROCESSFOR PRODUCTION OF ALUMINUM-CLADDING STEEL WIRE

In this study the process of cladding steel wires with aluminum is investigated experimentally. It is studied how the cladding process and the quality of products are influenced by the aluminum deformation temperature, the wheel speed, the temperature of steel wire, the wire speed and the steel wire tensile force. The relation among the process parameters above is discussed, and the effect of the aluminum deformation temperature on the coating microstructure is analyzed. This paper suggested a reasonable range of process parameters for producing aluminum cladding steel wires.

Corrosion resistance of aluminum alloy AA7022 wire fabricated by friction stir extrusion

Friction stir extrusion(FSE)is known as an innovative manufacturing technology that makes it possible to directly produce wire via consolidation and extrusion of metal chips or solid billets.In this study,wire samples were produced using aluminum alloy AA7022 machining chips by the use of the FSE.To this end,the microstructures and mechanical properties of the base material(BM)and the extruded samples were investigated.The corrosion resistance of the given samples was also determined using potentiodynamic polarization technique.The results showed that the samples manufactured at higher rotational speeds possessed good surface quality,the process temperature and the grain size similarly increased following the rise in rotational speed,and the mechanical properties consequently decreased.Using the FSE led to crystallite refinement,increase in volume fraction of grain boundaries,as well as re-distribution of precipitates affecting corrosion resistance.Furthermore,the findings of the corrosion tests revealed that the produced samples by the FSE had adequate corrosion resistance and the growth in die rotation rate augmented current density and subsequently reduced corrosion resistance.

Characteristic of laser-MIG hybrid welding with filling additional cold wire for aluminum alloy

The weld appearance, deposition rate, welding efficiency, stability of arc, laser keyhole characteristic, and weld property were studied by using a novel laser-MIG hybrid welding process with filling wire of aluminum alloy. The results were also compared with those by conventional laser-MIG hybrid welding process. It was found that with the suitable process parameters this novel welding process for aluminum alloy was stable and final weld bead had fine appearance. Compared to conventional laser-MIG hybrid welding process, during this novel welding process the stability of arc, the laser keyhole characteristic and the weld property were similar, while the keyhole cycle frequency and keyhole opening area had differences of 1.23% and 15.34%, respectively, and the welding efficiency increased by about 31% without increasing heat input.

DRAWING OF ALUMINUM-CLAD STEEL WIRE BY FORCE-FEED LUBRICATION

The force feed lubrication method is used for drawing aluminum clad steel wire. It is studied how deformation of wire and aspect of the lubricant film are influenced by the die angle, the reduction, the drawing speed and the gap between pressure die and wire. It has been concluded that when the factors above mentioned promote to thicken lubricant film, the drawing force is reduced and this favors the homogenous deformation of aluminum coating and steel core.

镍-铝丝材间隙对镍铝涂层显微组织及力学性能的影响

采用轧制与拉拔法制备了间隙不同的镍-铝丝材,研究了原材料中镍芯与铝皮间隙对涂层显微组织及力学性能的影响,利用体式显微镜、扫描电镜、拉伸试验机、显微硬度计检测了涂层的显微组织、成分和力学性能。结果表明:随着原材料中Ni与Al间隙增加,镍铝涂层的组织形貌、孔隙率无明显变化,涂层中Al2O3比例增加,NixAly金属间化合物比例降低;在力学性能方面,随原材料中Ni与Al间隙增加,镍铝涂层结合强度降低,显微硬度增加。

2219铝合金CMT电弧增材熔滴过渡行为

在冷金属过渡(cold metal transfer,CMT)电弧增材制造过程中,熔池的流动行为极易受到电弧和熔滴的影响,从而严重影响堆积层的稳定性和成形件质量.该文利用高速摄影结果及电信号参数波形图,引入热输入量计算公式,从特征电信号、熔滴过渡特征量、热输入量等方面定量分析了CMT+P模式下送丝速度及脉冲修正系数对熔滴过渡过程及单道成形形貌的影响,同时分析了脉冲变极性冷金属过渡(Advanced CMT,CMT+PA)模式下送丝速度及控制面板上的EP/EN修正系数η对熔滴过渡过程及单道成形形貌的影响,为后续工艺优化提供参考和指导.

冷拉变形对7050铝合金丝材组织与性能的影响

对7050铝合金丝材经冷拉变形后过时效态以及冷加工变形态的组织与性能进行了研究。结果表明,随着冷变形量的增加,晶粒拉长,屈服强度、抗拉强度和剪切强度增大。与冷拉态相比较,过时效态丝材的这些指标增加不明显;晶粒越均匀细小,合金丝材冷镦时越不易发生开裂。

送丝速度对铝/钢激光熔钎焊接头组织与性能的影响

采用ER2319焊丝进行了6061-T6铝合金/Q235镀锌钢光纤激光熔钎焊接,分析了送丝速度对接头成型、显微组织与力学性能的影响。结果表明:当激光功率为1.2 kW,焊接速度为1.2 m/min时,送丝速度在1.2~3.0 m/min范围内均可获得有效接头。接头的抗拉强度随着送丝速度的增加呈现先上升后减小的趋势,当送丝速度为2.4 m/min时平均抗拉强度达到最大值,为116.15 MPa。当送丝速度为1.8、2.4 m/min时,接头的上下表面的金属间化合物层可控制在10μm以内,而对接界面处的金属间化合物层厚度随着送丝速度的改变变化不明显,对接界面的IMC层主要由FeAl、FeAl_(2)、Fe_(4)Al_(13)相组成。接头的断裂形式为典型的解理断裂模式,而位于润湿铺展在钢表面的铝合金处则为韧性断裂。

高强铝合金电弧增材制造的研究进展

高强铝合金因具有高强度、低密度、优异的延展性和抗腐蚀性,成为了航空航天和汽车应用零件最常用的金属材料之一。电弧增材制造技术具有快速原位成形制造复杂结构零部件的能力,非常适用于中型或大型高强铝合金铝部件的制造。本文综合分析了高强铝合金电弧增材制造工艺和设备研发现状、高强铝合金电弧增材的固有属性和缺陷以及主要的性能优化手段,讨论了组织和性能的固有特征和复合增材制造技术对组织和性能的影响。针对电弧增材制造高强铝合金不可忽略的本质冶金缺陷、特征性能需求和多种优化工艺的优劣等问题,提出了电弧增材制造高强铝合金综合评价体系、成分设计和丝材开发、专用热处理制度和复合增材制造技术的协同性等发展方向,以期为电弧增材制造高强铝合金的性能提升和应用推广提供重要参考。

EFFECT OF ULTRASONIC POWER ON THE HEAVY ALUMINUM WEDGE BONDING STRENGTH

Eleven groups of wire bonding experiments are carried out on an experiment platform （restructured with a U3000 heavy aluminum wedge wire bonder）. Pure silicon aluminum wire （300 μm in diameter, 2.94-3.92 N in average pull force） and nickel coated aluminum substrates are used in the experiments. During the experiment process, only ultrasonic power rate parameter is changed and the other bonding parameters are kept as constant, The bonding force and time are 4.90 N and 100 ms respectively. After the bonding experiments, shear strength tests are carried out on the bonds as the bonding strength criterion. From those experiments and test results, some conclusions are obtained： In the small ultrasonic power rate conditions （about 20%-30%）, with the power increasing, the bonding strength enhances accordingly; However, in the large ultrasonic power rate conditions （about 45%-70%）, the bonding strength decreases accordingly and over bonding happens. Only when the ultrasonic power rate is in a moderate condition （about 35%-40%） can good and stabilized bonding strength be acquired.

5183高端铝合金焊材生产技术开发

通过研究5183高端铝合金焊材生产工艺,确定合金成分、开发熔体深度净化工艺和退火工艺,同时还开发出直接用电解铝液连续铸造-热连轧-冷连轧的短流程、低能耗的5183铝合金焊材生产技术,建成国内首套电解铝液连续铸造-热连轧-冷连轧铝合金焊丝线坯生产线,焊丝线坯最小尺寸达到直径2 mm。

沉积策略对电弧增材制造5356铝合金显微组织、缺陷和力学性能的影响

基于电弧增材制造技术(WAAM)研究往复扫描(RS)、振荡扫描(OS)和垂直扫描(VS)3种沉积策略对5356铝合金(AA5356)构件的影响,探讨5356铝合金构件的显微组织、缺陷和力学性能。结果表明:相比于RS和OS策略,VS策略使得构件的热量分布均匀。VS策略的显微组织主要由等轴晶组成,使得显微硬度最高值达到HV 77.25。VS策略使得构件的气孔率和微孔尺寸分别下降了45.52%和19.81%,从而改善了拉伸性能。因此,VS策略为获得显微组织均匀、力学性能优异的AA5356构件提供了一种新的解决方案。

搅拌摩擦辅助电弧增材制造铝合金研究进展

高性能铝合金兼具轻质、高强、耐腐蚀等优点,在航空航天和汽车制造等工业领域应用前景广阔。电弧增材制造技术集成形效率高、原材料和设备成本低、环境适应性强等优点于一身,在大尺寸铝合金构件制备方面具有显著优势。但复杂热循环导致的晶粒粗大、组织不均匀、残余应力和气孔缺陷等问题,给电弧增材制造铝合金带来了挑战。搅拌摩擦加工技术具有良好的组织细化、均匀化和致密化效果,已作为同步调控或后处理手段用于铝合金的增材制造中。针对近年来搅拌摩擦辅助电弧增材制造铝合金的装备系统、工艺参数、组织结构和力学性能等方面进行了综述,并分析了搅拌摩擦辅助电弧增材制造技术的形性调控机理,最后对复合增材制造技术的发展趋势进行了展望。

电弧增材制造2219铝合金热变形组织演变及本构方程

采用热压缩方法研究了电弧增材制造2219铝合金的热变形行为,变形温度为360~510℃,应变速率为0.01~10 s^(-1)。分析了温度和应变速率对流变应力和微观组织的影响,采用Zener-Hollomon参数的双曲正弦函数建立了电弧增材制造2219铝合金热变形本构方程。结果表明,电弧增材制造2219铝合金热压缩峰值应力随温度的升高和应变速率的降低而逐渐降低。电弧增材合金在420℃及以下温度仅发生滑移变形,450℃及以上发生动态再结晶,480℃为最佳锻造温度,发生完全动态再结晶,可有效细化增材晶粒。本构方程以动态再结晶温度(450℃)为临界点分为两段,动态再结晶温度以下变形激活能为212.53 kJ·mol^(-1),动态再结晶温度以上为163.37 kJ·mol^(-1)。沿晶界分布的共晶θ相在热压缩过程中发生破碎和固溶,变形温度越高或应变速率越小,固溶程度越高。

水平连铸-连续挤压-拉拔Al-0.65Mg-0.58Si-0.17Fe合金微观组织与性能研究

通过水平连铸-连续挤压-拉拔工艺制备了高强度高电导率Al-0.65Mg-0.58Si-0.17Fe合金线材,研究了加工工艺及热处理对合金微观组织、力学性能和电导率的影响。结果表明,水平连铸-连续挤压工艺提高了合金过饱和固溶度并显著细化了晶粒组织,拉拔过程引入的高密度位错改变了合金时效热处理过程中Mg_(2)Si相的析出行为,Al-0.65Mg-0.58Si-0.17Fe合金经水平连铸-连续挤压-拉拨,在155℃下时效3 h,其拉伸强度和延伸率分别为335 MPa和6.9%,电导率55.7%IACS。