Pure Copper Plates Research Articles

Effect of tool offset condition on mechanical and metallurgical properties of FSW dissimilar Al-Cu joint

Abstract Pure aluminum and copper plates of thickness 5 mm were used to fabricate the joints by FSW methods. Tool rotation speed of 1300 rpm, transverse speed of 50 mm/min and tool offset (from 0 mm to 2 mm with 2 mm step) to the aluminium side were used during the process and copper was fixed in the advancing side whereas aluminium fixed in the retreating side. The attained tensile strength was 92.5 MPa and the joint were fractured in TMAZ of aluminium side. The obtained tensile strength was almost closer to the aluminium base metal. Further, micro structural features and fractured tensile surface of the dissimilar joints were characterized by OM and SEM. Following this, all the results were interpreted with reference to tensile strength and yield strength.

RECENT DEVELOPMENT OF FRICTION STIR WELDING TOOLS FOR JOINING COPPER ALLOYS

In the present work an attempt was made to develop low cost high temperature wear resistance hardfacing tools. The hardfacing was applied on mild steel rod using Tungsten carbide powder by Plasma transferred arc welding (PTAW) processes. A comparative study was done to study the performance of hard facing tools with conventional tools. In this work, friction stir welding of pure copper plate of 6 mm thickness was investigated with an aim to understand the performance of tool materials on weld microstructure and tensile properties. From this investigation, it is found that the joints fabricated using PTA hardfaced tool yielded superior tensile properties compared to other joints. The optimum level of heat generation, formation of fine grains and higher hardness in plasticized zone are the main reasons for the superior tensile properties of these joints.

Effect of Laser Surface Modification (LSM) on laser energy absorption for laser brazing

Since the development of the laser in the 1960s a rapid development of research interests in science and technology took place. Since then, the need of laser application in industrials such as automotive, aerospace and electronics is increasing because of several advantages like automation worthiness, noncontact processing and product quality improvement. In this present study, the effect of Laser Surface Modification (LSM) on pure copper plate towards the laser energy absorption during indirect laser brazing process was studied. The laser brazing experiment was conducted inside a chamber under controlled vacuum pressure with 400Pa and irradiated with constant 140 Watt laser power. The defocusing features for laser brazing was used in order to find better focal position. Accordingly, the focal length for this laser brazing experiment was set to the focus point at 124 mm from the focal plane. Meanwhile, during LSM process, laser parameters such as laser scanning speed and focus length have been kept constant throughout the surface modification process. Yet, the laser power and laser frequency have been varied from 9 Watt to 27 Watt and 10 kHz to 80 kHz respectively. Apparently, surface roughness due to surface removal and oxide layer formation were presented during LSM process. These two surface integrities were found to be the factors of increasing laser energy absorption. It was discovered that an increase in surface roughness and oxide layer formation can absorb more laser energy which then results an increase in brazing temperature during laser brazing. This is because, increasing surface roughness will scatter the laser energy over a larger surface area, multiply the reflections in the surface irregularities while the oxide layer will enhance the interference phenomena of laser energy occurring inside the oxide layer. Both mechanisms increase laser energy absorptivity during laser brazing which results a high brazing temperature.

Enhancement of mechanical properties of Copper Brazed by laser surface modification

Nowadays, laser surface modification (LSM) has become the most advance technique for improving the surface properties for joining methods. This is due to its advantages such as cleaner, precise, more reliable and provides exact control compare to other surface modification techniques. This technique also applicable on wide range of materials, such as metal/alloy, ceramic and polymer. Brazing is a metal-joining process in which two or more metal items are joint together by melting and flowing a filler metal into the joint, the filler metal having a lower melting point than the base materials. The brazing process performed under a controlled atmosphere in vacuum tube furnace. Microscopic observations were made by use of both optical and electron microscopes. Fibre laser surface modification-brazing of 2 mm thick 99% pure copper plate in the lap joint configuration performing with Cu-based filler metal. There are three microgrooves were produced with three different laser power apply 15 watt, 21 watt and 27 watt. It found that successful brazing and wetting can be achieved by modified the surface for the base metal. The result of shear tensile test indicated that the highest shear strength was achieve in groove by using 27. This is because of its excellent of its excellent spreading behaviour of molten filler metal, largest bonding interface area and suitable intermetallic compound (IMC) distribution.

Pulsed laser ablation route assisted copper oxide nanoparticles doped in Polyethylene Oxide/Polyvinyl pyrrolidone blend for enhancement the electrical conductivity

Polyethylene Oxide/Polyvinyl pyrrolidone blend was doped by Copper Oxide Nanoparticles (CuONPs) prepared by laser ablation process. Synthesized Copper oxide nanoparticles were prepared by ablating pure copper plate immersed in DDW by nanosecond Nd:YAG laser in different times. PEO/PVP/CuONPs nanocomposites have been synthesized via casting technique. Effect of CuONPs doping on enhancing PEO/PVP have been obtained. The influence of various times of laser ablation on the properties of the synthesized nanocomposite films was analyzed via several techniques. SEM and XRD proved the interaction between PEO/PVP blend and CuONPs. The presence of the distinctive absorption peak at UV–Vis range at 277 nm was due to copper oxide surface plasmon resonance (SPR). The direct and indirect optical band gap values illustrate a decrease following doping of copper oxide inside PEO/PVP matrix. Dielectric constant and dielectric loss activity gradually diminished as the frequency rises. AC conductivity were increased as laser time increased.

One-Pot Pulsed Laser Ablation route assisted copper oxide nanoparticles doped in PEO/PVP blend for the electrical conductivity enhancement

Polyethylene Oxide (PEO)/Polyvinyl pyrrolidone (PVP)/Copper Oxide Nanoparticles (CuONPs) were synthesized by one-step Pulsed Laser Ablation of pure Copper plate immersed in PEO/PVP (70/30wt.%) solution. PEO/PVP/CuONPs composite films were prepared using casting method. The role of copper nanoparticles on modifying PEO/PVP was demonstrated. The effect of different laser ablation times on the characterization of the prepared PEO/PVP/CuONPs composite films have been studied via XRD, UV–vis, PL, SEM, and Ac conductivity. XRD and SEM confirm the complexation between CuONPs and PEO/PVP matrix. The appearance of the characteristic absorption peak at 275nm in UV–vis spectrum was attributed to the surface plasmon resonance (SPR) of CuONPs. The values of the direct and indirect optical band gap show a decreasing after doping PEO/PVP matrix by CuONPs. PL analysis confirmed that the existence of the CuO nanoparticles comprehensively reorders the delocalized n-electron system of PEO/PVP blend matrix. The behavior of dielectric constant and dielectric loss are progressively decreased as the frequency increased. The values of AC conductivity are increased as the laser ablation time increased. M' and M″ values are increased by increasing the concentration of CuONPs in the PEO/PVP blend matrix, which induces an increase in the ion conduction of the prepared samples.

MATLAB Image Treatment of Copper‐Steel Laser Welding

Continuous Yb:YAG laser keyhole welding of the pure copper plate to steel 316L sheet is performed for different laser parameters. The laser‐generated welding keyhole and weld melted zone are observed by a high‐speed camera. The image is treated by MATLAB and simple code is built to calculate the keyhole and melted zone area. This treatment is validated by the actual welding measurements, and the accuracy of the measurements is tested by the confidence interval law. The images obtained of keyhole and melt zone area in dissimilar laser welding are treated and analyzed to study the effect of changing the laser parameters.

Structure of materials ultrasonically consolidated from coarse-grained and nanostructured plates of commercially pure copper

Ultrasonic consolidation of commercially pure copper plates with coarse-grained and ultrafine grained structures was carried out. Copper plates in both states were joined by ultrasonic welding using the same route. Consolidated samples were studied in a cross section parallel to the oscillation direction. The compressive strain value and the joint quality in relation to the initial structure of the material were studied. It is shown that the ultrasonic consolidation is a promising method of additive manufacturing using bulk nanostructured materials.

Effect of Operational Parameters on the Thermal Performance of Flat Plate Oscillating Heat Pipe

Abstract Flat plate oscillating heat pipe (FP-OHP) is a unique heat transfer device and considered as a promising candidate for effective heat transfer device in electronics industries. A number of theoretical studies and experimental investigations have been carried out on FP-OHP in the past decades after its invention. However, due to the operational characteristics of FP-OHP, the effect of various parameters on the thermal performance of FP-OHP has not been completely revealed so far. This paper attempts to discuss the effect of operational parameters on the thermal performance of FP-OHP. In this study, the FP-OHP was investigated with different charge ratios, orientations, working fluids, and heat loads from 10 W to 150 W. In order to investigate the effect, 18 parallel square channels of 2 × 2 mm2 are machined onto pure copper plate (93 × 70 × 8 mm3) to form FP-OHP. DI water, ethanol, methanol, acetone, and FC-72 are investigated. The measured thermal resistance was strongly dependent on operational parameters. The optimum performance was observed with acetone with a charge ratio of 70% in the vertical orientation. The lowest thermal resistance of 0.39 °C/W is achieved using acetone as a working fluid at 100 W. A Kutateladze number (Ku) was used to compare the experimental data and found to be suitable for prediction of the thermal performance of FP-OHP with standard deviation of 15%.

Numerical simulation of friction stir welding of pure copper plates

Friction Stir Welding (FSW) is a joining process which is performed at low temperatures, lower than the melting temperature of the base material, thus it is considered a solid state welding process. This feature makes it suitable for copper welding, material whose thermal diffusivity is higher than that of most steel alloys. Large heat losses identified at copper welding by fusion welding processes are thus reduced using FSW process. Because of the shown efficiency and the innovative character of this process, many actions have been initiated in order to optimize it. The aim of this paper is to develop a three-dimensional coupled thermo-mechanical finite element (FE) model of FSW process for pure copper plates using the Coupled Eulerian-Lagrangian (CEL) formulation given in the FE code ABAQUS V6.13. The CEL formulation is one of the few formulations that are capable of handling with such large deformations. The developed numerical model was validated by comparing its results related to the temperatures calculated in the process time with those measured in performed experiments using the same process parameters. This model was capable of simulating the FSW of copper plates and of anticipating the temperature distribution and burrs formation in the weld bead.

Microstructure Evolution and Tensile Behavior of Dissimilar Friction Stir-Welded Pure Copper and Dual-Phase Brass

6-mm-thick pure copper and dual-phase brass plates were joined using friction stir welding (FSW). The role of plate location prior to welding and the tool rotational speed on the microstructure evolution was evaluated and correlated to the tensile properties of the joint. All the joints with copper on advancing side produced defects. Typical zones commonly found in FSW joints were observed. TMAZ was not found on the copper side, and no coarsening of grains was noticed in the HAZ on the brass side. The microstructure of the weld zone was heterogeneous and grouped into three categories. The plate position and the tool rotational speed influenced the material flow and the formation of different structures. The weld zone was further characterized by ultra-fine grains, dislocations and annealing twins. The hardness across the weld zone was varying considerably. The process parameter had an opposite effect on the hardness of brass and copper portion of the weld zone. The joints with brass on advancing side showed higher tensile strength. The fracture location and surfaces were further reported.

Effect of copper based filler composition on the strength of brazed joint

Vacuum brazing of copper-based filler was performed using pure copper plate as its based metal. The brazed joint was obtained at different temperatures, 680oC and 730oC, with same holding time, which is 30 minutes. MBF 2005 (Cu, 5.7wt.%Ni, 9.7wt.%Sn, 7.0wt.%P), MBF 2002 (Cu, 9.9wt.%Ni, 4.0wt.%Sn, 7.8wt.%P) and VZ 2250 (Cu, 7.0wt.%Ni, 9.3wt.%Sn, 6.3wt.%P) alloys were used as brazing filler materials. The intermetallic compound (IMC) and mechanical properties of the joints were investigated in detail. The result show that the interfacial microstructure of the brazed joints is Cu3P and (CuNi)2P. As the brazing temperature increase from 680oC to 730oC, the IMC become thicker leading to decrease in joining strength due to brittle IMC formation. The maximum shear strength reached 112 MPa at 680oC for MBF 2002 and 129 MPa at 730oC for MBF 2005. Hence, it is found that the composition of filler effects the strength of brazed joint.

Microstructures and Properties of Friction Stir Welded Al-Cu Lap Joints

Friction stir welded lap joints of 5083 aluminum alloy plates with thickness of 2mm and T2 pure copper plates with thickness of 3mm were prepared, and the microstructures and properties of lap joints were investigated. The results showed that Al and Cu interdiffusion occurred at the interface of the lap joints, the grains in the stir zone of Al were refined and the microhardness increased sharply. The joint of Cu can be divided into four parts, including the nugget zone (NZ), thermo-mechanically affected zone (TMAZ), heat affected zone (HAZ) and base metal (BM). Using the optimum welding parameters (rotation speed of 900rpm and welding speed of 100mm/min), the lap joints were well formed. There were fewer welding defects and the average shear tensile force reached 3.155KN. Also, the ductile-brittle hybrid fracture occurred at the transitional zone of the advancing side of the Al plates. XRD results showed that intermetallic compounds (IMCS) mainly composed of Al2Cu and AlCu4 were produced in the interface of the lap joints during welding.

Ultrasonic vibration assisted friction stir welding of aluminium alloy and pure copper

A new ultrasonic vibration assisted friction stir welding (UVaFSW) system was used to successfully join AA6061-T6 aluminium alloy and C10100 pure copper plates. The effect of ultrasonic vibration on the joint formation, macrostructural features, microstructure and mechanical properties of the joints was investigated. The novel UVaFSW process was found to enhance the joint formation mechanism and mechanical properties. The joint strength was found to increase with rotational speed up to 600 rev/min and then decrease due to higher heat inputs. Material flow behaviour of the reacting materials was enhanced, the structured layers exhibited more homogenous features, and the intermesh of the joint interfaces was improved. Ultrasonic vibration influences the fracture mechanism of the Al-Cu joint by shifting the fracture location to the heat affected zone in the Al side of the joint, and the fracture surface displayed a ductile fracture mode. Whereas, in the joints without ultrasonic vibration, the fracture occurred mainly at the thermomechanically affected zone in the Cu side of the joints, and the fracture surface showed a mixed brittle-ductile fracture characteristic.

Mechanical and Microstructural Properties of Friction Stir Welded Dissimilar Aluminum Alloys and Pure Copper Joints

Joining dissimilar metal alloys such as aluminum and copper is very difficult to be done because of alterations in chemical, metallurgical and physical behavior. Friction Stir Welding (FSW) is a solid-state welding technique which is one of the new methods used for joining the dissimilar metal. The material used is aluminum alloy 5052 and pure copper plates. The welding parameters were carried out with variable geometry shape of pin tools: taper and threaded cylindrical pin tools. Also preheating were performed on the part of copper plates with temperatures at both 25°C and 200°C. The friction stir welding of dissimilar joints was carried out at the rotary tool speed of 2800 rpm with the angle of 1 degree and the welding travel speed of 2 mm/sec. All welds were then carried out to several mechanical testing and microscopic observation. The results show that the variable geometry shape of pin tools and pre-heating on the copper part affect the microstructure grain size and the formation of Al-Cu inter-metallic phases. The creation of different structures influences the mechanical properties of the friction stir welds. The hardness of welds using threaded pin tools is higher than the tapper one. However, the tensile strength of dissimilar welds using the threaded cylindrical pin tools is lower than the tapper one. The fracture location commonly occurs at the part of aluminum plates having a brittle intermetallic phase.

Effect of stacking fault energy on the restoration mechanisms and mechanical properties of friction stir welded copper alloys

Pure copper and Cu-Zn plates were friction stir welded under the same condition to evaluate the effect of stacking fault energy on the microstructural evolution and mechanical properties of the joints. For this aim, microstructure and texture of the joints were systematically characterized by electron backscattered diffraction and transmission electron microscopy. Moreover, to study the mechanical properties of the different microstructural zones of the joints, nanoindentation tests were employed. The results showed that in pure copper, continuous dynamic recrystallization was the only restoration mechanism for the formation of new grains. By adding zinc into copper, namely decreasing stacking fault energy, both continuous and discontinuous dynamic recrystallization mechanisms occurred. To this end, the effect of stacking fault energy on the restoration mechanisms has been summarized by schematic models. Moreover, the effect of the restoration mechanisms on the yield strength and strain hardening behavior of the joints has been scrutinized.

High‐performance Cu/Al laminated composites fabricated by horizontal twin‐roll casting

AbstractHorizontal twin‐roll casting technology was successfully introduced to produce high‐performance copper/aluminum (Cu/Al) laminated composites. The interface morphology, electrical properties and peeling strength after different annealing and cold rolling processes were investigated and contrasted with Cu/Al clad plates fabricated by conventional methods. The results show that sound metallurgical bonding between the copper and aluminum matrix can be attained after the horizontal twin‐roll casting processes and Al2Cu is the only intermetallics at the interfacial region, the thickness of interfacial interlayer is about 0.7 μm. The peeling strength is 31.4 N/mm and can be further increased to 37.1 N/mm after annealing at 250 °C. However, higher temperature like 400 °C will cause the excessive growth of intermetallics so that peeling strength sharply decreases to 9.2 N/mm. Electrical conductivity of the clad plate is 51 MS/m. At the same electrical current intensity, the temperature‐rise of the composite plate is between the pure copper plate and the aluminum plate, and closer to the copper plate. All of the properties are outstanding than that of Cu/Al clad plate fabricated by conventional methods.

Effect of Welding Parameters on the Mechanical and Metallurgical Properties of Friction Stir Spot Welding of Copper Lap Joint

In this work, 2-mm-thick pure copper plates are joined using friction stir spot welding (FSSW) at different rotational speeds, plunging rates and dwell times. Effects of these process parameters on the quality of the weldments, bonding region and shear–tensile failure load of the joints are studied. A maximum shear–tensile failure load of 5.5 kN was obtained at 1200 rpm rotational speed, 20 mm/min plunging rate and 2-s dwell time. Interestingly, this set of welding conditions also resulted in end of partial metallurgical bonded region along the interface that is free of voids and cracks which indicates strong weldments. Fracture surface morphology was also investigated, and ductile fracture mode was observed for 1200 rpm, 20 mm/min and 2 s which showed high elongation before complete fracture. Moreover, mechanical energy consumed during welding was estimated for each set of welding conditions under study and was found significantly affecting shear tensile failure load of the welds.

Modeling And Prediction of Mechanical Strength in Electron Beam Welded Dissimilar Metal Joints of Stainless Steel 304 and Copper Using Grey Relation Analysis

Aircraft industries witness an extensive variety of utilizations in unique welded joints thinking about the benefit of quality and high corrosion protection. In any case, joining of dissimilar materials is more mind boggling because of the distinction in material properties. In this investigation dissimilar metal joints of pure Copper plates and Stainless Steel 304 plates of 3mm thickness were welded with Electron Beam Welding. The welding input parameters like Welding speed, Beam current and Work distance liable to quality of weld are considered. Plan of analysis has been made utilizing Taguchi strategy with three levels of input values. Ultimate tensile strength and hardness number were found to decide the mechanical quality. Both the yield esteems are consolidated for expectation and optimized using Gray Relation Analysis (GRA). The impacts of the input parameters towards weld quality were analyzed using ANOVA.

Establishing the Dependence of Output Parameters Depending on Local Process Conditions for Friction Stir Welding of Pure Copper Plates

Welding copper and its alloys is usually difficult to achieve by conventional fusion welding processes because of high thermal diffusivity of the copper, which is at least 10 times higher than most steel alloys, in addition to this, there are the well-known disadvantages of conventional fusion welding represented by necessity of using alloying elements, a shielding gas and a clean surface. To overcome these inconveniences, Friction Stir Welding (FSW), a solid state joining process that relies on frictional heating and plastic deformation, is being explored as a feasible welding process. In order to achieve an increased welding speed and a reduction in tool wear, this process is assisted by another one (TIG) which generates and adds heat to the process. The research includes two experiments for the FSW process and one experiment for tungsten inert gas assisted FSW process. The process parameters that varied were the rotational speed of the tool [rpm] and the welding speed [mm/min] while the compressive force remained constant. The purpose of this paper is to correlate the evolution of temperature, tensile strength, elongation and microscopic aspect with the linear position on the joint (local process parameters) for each experimental case and then make comparisons between them, and to identify and present the set of process parameters that has the best mechanical properties for this material.