基于纳米颗粒热效应的飞秒激光高效直写金属铜微结构

在Cu(NO_(3))_(2)前驱体溶液中添加硅纳米颗粒,采用飞秒激光在透明基底表面成功直写了导电金属铜微结构。前驱体溶液中的硅颗粒作为吸光粒子吸收激光能量后对溶液进行加热,使Cu^(2+)还原为金属铜并沉积在基底表面。结果表明:当激光光强为5.32×10^(9)~8.51×10^(9)W·cm^(-2)、扫描速度为100~500mm·s^(-1)时,微结构主要由铜、Cu_(2)O及微量硅组成,铜含量及微结构的导电性随着光强的增加或扫描速度的降低而逐渐增加;在光强为5.32×10^(9)W·cm^(-2)、扫描速度为100mm·s^(-1)的条件下,铜微结构的方阻为0.28Ω·sq^(-1),电阻率为4.67×10^(-6)Ω·m。与已有的飞秒激光直写铜微结构的技术相比,这种方法使激光光强降低了2个数量级,直写效率提高了1~3个数量级。

A gradient nano/micro-structured surface layer on copper induced by severe plasticity roller burnishing

In order to investigate a gradient nano/micro-structured surface layer on pure copper produced by severe plasticity roller burnishing （SPRB） and grain refinement mechanism, the microstructure characteristics and material properties of sample at various depths from the topmost surface were investigated by SEM, TEM, XRD, OM etc. The experimental results show that the gradient nano/micro-structure was introduced into the surface layer of over 100μm in thickness. The remarkable increase in hardness near the topmost surface was mainly attributed to the reduced grain size. The equiaxed nano-sized grains were in random orientation and the most of their boundaries were low-angle grain boundaries （LAGBs）. The coarse grains are refined into the few micro-sized grains by dislocation activities;deformation twinning was found to be the primary form for the formation of submicron grains;the formation of nanostructure was dominated by dislocation activities accompanied with rotation of grains in local region.

Microstructure evolution of copper doped beryllium thin films

Copper （Cu） doped beryllium （Be） thin films were deposited on silicon substrates by using a simple ion beam sputtering method, which can also realize the varying of Cu doping concentration. Detailed morphological and structural characterizations of the samples clearly disclose a microstructure evolution of films upon doping Cu. Doping Cu can effectively suppress film grain growth, causing a small grain size as well as uniform size distribution. Furthermore, doping Cu affects the crystallographic texture of film, which leads to the formation of more compact film structure. In particular, the surface smoothness of the doped films is significantly improved, which makes them promising candidates for various applications.

Chemical etching process of copper electrode for bioelectrical impedance technology

In order to obtain bioelectrical impedance electrodes with high stability, the chemical etching process was used to fabricate the copper electrode with a series of surface microstructures. By changing the etching processing parameters, some comparison experiments were performed to reveal the influence of etching time, etching temperature, etching liquid concentration, and sample sizes on the etching rate and surface microstructures of copper electrode. The result shows that the etching rate is decreased with increasing etching time, and is increased with increasing etching temperature. Moreover, it is found that the sample size has little influence on the etching rate. After choosing the reasonable etching liquid composition （formulation 3）, the copper electrode with many surface microstructures can be obtained by chemical etching process at room temperature for 20 rain. In addition, using the alternating current impedance test of electrode-electrode for 24 h, the copper electrode with a series of surface microstructures fabricated by the etching process presents a more stable impedance value compared with the electrocardiograph （ECG） electrode, resulting from the reliable surface contact of copper electrode-electrode.

Influence of Copper Stress on Ultra-structure of Wheat Seedlings

Transmission Electron Microscope (TEM) Technology was used to investigate the effect of 25,100 and 200 mg/kg copper on ultra-structure of root tip and leaf blade of wheat. Result showed that serious damage was found with Copper of 25,100 and 200 mg/kg. Plasmolysis,concentrated cytoplasm,chloroplast inflation,lamellar structure disturbance,capsule disappearance and disintegration,mitochondria structures ambiguity and vacuolization were all symptoms under Cu stress. There were positive correlation between concentration of coper stress and the degree of injury,and the degree of injury of copper were different in different organelles. Mitochondria were the most sensitive organelles,and there was patient difference in the same organelles of different parts.

Influence of cerium on microstructures and mechanical properties of Al-Zn-Mg-Cu alloys

Effect of element cerium （Ce） on microstructure and mechanical properties of A1-Zn-Mg-Cu alloys has been investigated by transmission electron microscopy （TEM）, scanning electron microscopy （SEM）, differential scanning calorimetry （DSC） and hardness test. The results show that addition of Ce can remarkably refine the as-cast grains and eutectic microstructure. A transformation from Mg（Zn,Cu,A1）2 phase to A12CuMg phase is observed during homogenization. Furthermore, the Ce addition introduces changes in the precipitation process and consequently in the age-hardening behavior of the alloy. Microstructural measurements reveal that the addition of Ce promotes the precipitation of η＇ phase, but it also partly retards the precipitation of GP zones. The density of precipitates decreases in a certain degree and rod-like η＇ precipitates increase when Ce content is from 0.2% to 0.4% （mass fraction）.

Effects of yttrium on microstructure and mechanical properties of Mg-Zn-Cu-Zr alloys

The effects of yttrium addition on microstructure and mechanical properties of as-cast Mg-6Zn-3Cu-0.6Zr-xY(x=0,0.5, 1.0,1.5 and 2.0,mass fraction,%)(ZCK630+xY for short in this study)alloys were investigated by means of OM,XRD and SEM. The results show that the average grain size of Mg-Zn-Cu-Zr magnesium alloy is effectively reduced(from 57μm to 39μm)by Y addition.The analysis of XRD indicates the existence of I-phase(Mg3Zn6Y)and W-phase(Mg3Zn3Y2)in ZCK630 alloys with Y addition.The ultimate tensile strength of ZCK630 alloys is significantly deteriorated with increasing Y addition,which is possibly related to the continuous networks of intergranular phases and the increase of W-phase.

Microstructure of aluminum/copper clad composite fabricated by casting-cold extrusion forming

An aluminum/copper clad composite was fabricated by the casting-cold extrusion forming technology and the microstructures of the products were observed and analyzed.It is found that aluminum grains at the interface are refined in the radial profiles of cone-shaped deformation zone,but the grains in the center maintain the original state and the grain size is non-uniform.A clear boundary presents between the refined area and center area.In contrast,the copper grains in the radial profiles have been significantly refined.In the center area of the copper,the grains are bigger than those at the boundary.On the surface of the deformable body,the grain size is the smallest,but with irregular grain morphology.After the product is entirely extruded,all the copper and aluminum grains are refined with small and uniform morphology.In the center area,the average diameter of aluminum grains is smaller than 5 μm,and the copper grain on the surface is about 10 μm.At the interface,the grain size is very small,with a good combination of copper and aluminum.The thickness of interface is in the range of 10-15 μm.Energy spectrum analysis shows that CuAl3 phase presents at the interface.

Effect of processing routes on microstructure and mechanical properties of 2014 Al alloy processed by equal channel angular pressing

Al-Cu alloy was deformed through equal channel angular pressing(ECAP) by routes A,Ba,Bc and C up to 5 passes.ECAP was done using a 90° die for three different conditions,namely 1) as received,2) solutionised at 768 K for 1 h and 3) solutionised at 768 K for 1 h + aged at 468 K for 5 h.The microstructure,microhardness and tensile strength were studied for all the three conditions and four routes.Significant improvement in hardness(HV 184 after five passes) and strength(602 MPa after three passes) was observed in solutionised and aged 2014 Al alloy deformed through route Bc.Microstructure evolution was reasonably equiaxed in route Bc with aspect ratio of 1.6.Solutionised and aged 2014 Al alloy deformed through route Bc was identified to have better microstructure and mechanical property than the other processing routes and conditions.

Evolution of surface roughness of a cast Al-Si-Cu piston alloy during thermal exposure

In the present work,samples of Al-Si-Cu piston alloy after T6 heat treatment were exposed for 2 h at temperatures ranging from 400 to 550°C.The evolution of surface roughness and microstructure of the alloy during thermal exposure was studied by combination methods of roughness profiles,optical and scanning electron microscopy as well as XRD analysis.It is found that the roughness and mass of the alloy increase with the raise of the thermal exposure temperature,and the increasing rates of them are slow as the exposure temperature is below 500°C,but accelerates abruptly when the temperature is higher than 500°C.The variation of surface roughness of the alloy is closely related to phase transformation and oxidation during the thermal exposure.

Effect of heat treatment on microstructures and mechanical properties of Al-6Zn-2Mg-1.5Cu-0.4Er alloy

The microstructures and mechanical properties of Al-6Zn-2Mg-1.5Cu-0.4Er alloy under different treatment conditions were investigated by transmission electron microscopy （TEM） observation, and tensile properties and hardness test, respectively. The relationship between mechanical properties and microstructures of the alloys was discussed. With trace Er addition to A1-Zn-Mg-Cu alloy, Er and Al interact to form Al3Er phase, which is coherent with a（A1） matrix. The results show that Al-Zn-Mg-Cu alloy after retrogression and re-ageing （RRA） heat treatment exhibits higher tensile strength, ductility and conductivity.

Microstructures and interfacial interactions of Al_(2)O_(3)whiskers and graphene nano-platelets co-reinforced copper matrix composites

The mechanical properties and microstructures of Al_(2)O_(3)whiskers and graphene nano-platelets(GNPs)co-reinforced Cu-matrix composites were studied.Cu-matrix composites with a variation of GNPs amount were fabricated by mechanical alloying followed by vacuum hot-pressing sintering and hot isostatic pressing.The Cu-matrix composite with 0.5 wt.%GNPs(GNPs-0.5)suggests a good interfacial bonding of both Cu/C and Cu/Al_(2)O_(3)interfaces.Both the hardness and compressive strength of Cu-matrix composites show a consistent tendency that firstly increases to a critical value and then decreases with increasing GNPs amount.It is suggested that the most possible strengthening mechanisms of both GNPs and Al_(2)O_(3)whisker working in the Cu-matrix composites involve energy dissipating and load transfer,as well as grain refinements for GNPs.The synergetic effect of GNPs and Al_(2)O_(3)whiskers is highlighted that the embedded GNPs would hinder the crack path generated at the Al_(2)O_(3)/Cu interface and enhance the already outstanding strengthening effect that Al_(2)O_(3)whiskers provide.

Microstructure and texture evolution of cold drawing <110> single crystal copper

By means of electron backscattering diffraction and transmission electron microscopy the microstructure and texture of drawn single crystal copper with initial orientation （110） parallel to axial direction have been investigated in the present work. In or- der to analyze the effect of initial orientation on microstructure and texture of drawn copper, the results of the drawn （110） sin- gle crystal copper wires have been compared with （100） and （111） single crystal copper wires. It is found that the grain subdi- vision of （110） single crystal is more evident than that of （100） and （111）, and the textures consisting of （111） and （100） abruptly form in the drawn （110） single crystal. At high strains, due to shear strain, the distribution of fiber textures is imho- mogenous along the radial direction of drawn （110） single crystal copper wires. （100） is near the surface and （111） is at the center. The microstructure results of drawn （110） single crystal show that at low strains, it can be characterized as two kinds of geometrically necessary boundaries with noncrystalline character. At medium strains, S bands can be observed. At high strains, lamellar boundaries form. Mean misofientation and average spacing of dislocation boundary are larger in drawn （110） single crystal, as compared with （111） and （100）. In drawn （110） single crystal with high strains, the bimodal distribution forms at lower strains than in drawn （100） single crystal, which is because the dislocation boundaries with high angle are contributed by not only the boundary between （111） and （100） fiber textures but also the boundary in （111） or （100） texture.

Interfacial microstructure of Cu Cr/1Cr18Ni9Ti bi-metal materials and its effect on bonding strength

The Cu Cr/1Cr18Ni9 Ti bi-metal materials were prepared by the solid-liquid bonding method. The microstructures, mechanical properties and formation mechanism of the bonding interface were studied. The results show that there exists a serrated transition layer with a certain width at the interface of Cu Cr/1Cr18Ni9 Ti bi-metal materials, and the transition layer consists of Fe-based and Cu-based solid solutions. The elastic modulus and hardness reach the maximum values at the interface closing to the 1Cr18Ni9 Ti zone. The bonding temperature has a significant effect on the width and morphology of the transition layer. The interfacial bonding strength is at least 30% higher than that of the Cu Cr alloy, and the tensile fracture occurs at the side of the Cu Cr alloy rather than at the bonding interface.