Copper Sides Research Articles

Diffusion Welding for TC4 Titanium Alloy/T2 Copper with Vanadium Foil

TC4 titanium alloy (TC4) was vacuum diffusion welded to T2 copper (T2) with vanadium (V) foil as an interlayer. The influence of process parameters on elemental diffusion behavior, microstructure evolution, and shear performance of welded joints was explored. An obvious solid-solution diffusion zone appeared in the welded interface between TC4 and V, but no distinct diffusion zone formed in the joint interface of V/T2. The solid-solution phases of (Ti6, V)ss, (Ti3, V)ss, and (Ti, V7)ss appeared in the interface of TC4/V. The crystallographic orientations of (Ti6, V)ss, (Ti3, V)ss, and (Ti, V7)ss phases in high-resolution transmission electron microscope images were (002), (201), and (121), respectively. The lattice mismatch between (Ti6, V)ss and (Ti3, V)ss was calculated to be 11.9%. The activation energy to form a stable solid solution between titanium and vanadium was 226.6 kJ/mol. The highest shear strength of the welded joint reached 160 MPa, obtained at 860°C (1580°F) for 60 min. The joint fractured along the interface of V/T2, illustrating that the solid-solution structure between Ti and V was stronger than the metallurgical bonding between V and Cu. The fracture surface of the welded joints revealed a river pattern and ladder topography, representing a cleavage fracture mode. FCC-Cu, BCC-V, and β-Ti were detected on both fracture surfaces of the TC4 titanium alloy and T2 pure copper sides. The influence of welding temperature on the diffusion of V in Ti was greater than on Ti in V, and Ti and Cu diffused faster than V in the joint.

The Analysis of Current Strength and Electrolysis Process Time of Silver (Ag) Plating on Copper Metal

The purpose of this study was to determine the effect of adding time and increasing electric current strength to the electrolysis process on the quality of Ag metal coating on Cu metal. In this study, the electrolysis process was given different current variations, namely 4A, 6A and 8A and the electrolysis process time was 30, 45 and 60 minutes and the electrolyte concentration remained 0.6 M. To analyze the coating mass and thickness measurements were carried out while to determine the good quality of the coating process was determined using SEM. The results of the study showed that the best coating quality was 60 minutes of coating time and 8A current with a thickness of 4.85 μm. The SEM results to determine the good quality of the coating process on the surface of Ag metal on Cu metal can be seen in the copper sample (concentration 0.6 M, 60 minutes, 8A) which shows that the surface results on copper are slightly better and neater but there are still lots of copper sides which is not silver plated.

Investigation of forming limit diagram and mechanical properties of the bimetallic Al/Cu composite sheet at different temperatures which fabricated by explosive welding

This research aims to investigate the mechanical properties, fractography and formability of Al/Cu two-layer composite sheets at three temperatures (23 °C, 120 °C and 220 °C). The bimetal sheet was fabricated by the explosive welding method. The anisotropy of the Al/Cu bimetallic composite sheet was investigated. The result showed significant anisotropy in the Al/Cu composite sheet due to the explosive welding process. The Vickers hardness measurements demonstrated that the hardness in both aluminum and copper sides increased because of the work hardening phenomenon. The fractography of the surfaces was investigated by the scanning electron microscope after tensile tests to study the effect of temperature and the direction, which the samples prepared for the tensile test with respect to the explosion direction, on the mechanism of the fracture. For the tensile test, the samples were prepared parallel to the detonation direction [Formula: see text] and two other directions with respect to the explosion direction [Formula: see text] from the AA1100/Cu10100 bimetallic sheet. Finally, the forming limit diagram of the Al/Cu composite sheet was determined at the three mentioned temperatures. The results demonstrated that temperature and the direction had a considerable effect on the mechanism of the rupture and formability. As the temperature of the specimen rises, the regions that brittle fracture happened became less and the formability improved significantly. The formability of the Al/Cu composite sheet enhanced about 34.8% when the temperature increased from 23 °C to 120 °C and 67.5% when it increased from 120 °C to 220 °C.

Effect of Next-Nearest-Neighbor Electron Hopping on Superconducting Gap of Cuprate Superconductors

We study here a single band Hamiltonian model to describe the effect of next-nearest-neighbor (NNN) electron hopping on superconducting gap in Cuprates. The Hamiltonian consists of nearest-neighbor (NN) and next-nearest-neighbor (NNN) electron hopping integrals between the copper sides. By taking d-wave pairing symmetry into account, BCS type superconducting interaction is studied. By applying Zubarev’s Green function technique, the total Hamiltonian is solved. From the correlation function, the temperature-dependent superconducting gap (SC) equation is derived and is computed self-consistently by using technique [Formula: see text] grid points of the electron momentum. By varying SC coupling, chemical potential, J-T coupling parameter and second-nearest-neighbor electron hopping integral, the evolution of the order parameter is investigated.

Microscopic study of the role of second nearest neighbour spin density wave coupling and electron hopping on superconducting gap

We report here a tight binding single band model Hamiltonian to study the role of spin density wave interaction and superconductivity. The Hamiltonian consists of nearest and next nearest neighbour electron hopping between the copper sides. The spin density wave interaction also includes nearest-neighbour and the next-nearest-neighbour spin interactions within a mean field approximation. BCS type superconducting interaction is considered taking d-wave pairing symmetry. By using Zubarev's Green function technique the Hamiltonian is solved. The antiferromagnetic and the superconducting gap equations are derived from the correlation functions and are solved self-consistently technique 100 × 100 grid points of the electron momentum. The evolution of these two order parameters are investigated by varying hole doping concentration, superconducting coupling, spin density wave coupling and second nearest neighbour electron hopping integrals.

Microscopic study of the role of second nearest neighbour spin density wave coupling and electron hopping on superconducting gap

We report here a tight binding single band model Hamiltonian to study the role of spin density wave interaction and superconductivity. The Hamiltonian consists of nearest and next nearest neighbour electron hopping between the copper sides. The spin density wave interaction also includes nearest-neighbour and the next-nearest-neighbour spin interactions within a mean field approximation. BCS type superconducting interaction is considered taking d-wave pairing symmetry. By using Zubarev's Green function technique the Hamiltonian is solved. The antiferromagnetic and the superconducting gap equations are derived from the correlation functions and are solved self-consistently technique 100 × 100 grid points of the electron momentum. The evolution of these two order parameters are investigated by varying hole doping concentration, superconducting coupling, spin density wave coupling and second nearest neighbour electron hopping integrals.

Measurement of residual stresses in dissimilar friction stir-welded aluminium and copper plates using the contour method

ABSTRACTThe longitudinal residual stresses in the friction stir-welded plates of 5A06 aluminium and pure copper were determined using the contour method. The results revealed the presence of high tensile and compressive residual stresses on the aluminium and copper sides, respectively. The residual stresses were detected on the weld zone as well as the thermo-mechanically affected zone (TMAZ) of the aluminium plate. In contrast, the compressive residual stresses in the copper plate had a much narrower width along the weld line. Peak tensile stresses up to 240 MPa were found in the TMAZ of the aluminium plate.

Microstructure and Mechanical Properties of Explosive Weld Copper-Mild Steel Joint

Mild steel and copper was joined with explosive welding using suitable parameters to obtain a copper-mild steel joint of high integrity. There was no diffusion, melting and formation of intermetallic zone between the bonded plates. An inter-mixed zone of the base materials is observed with a span of 1300 μm around the interface. Significant hardening and softening of the microstructure was observed on the copper and steel sides around the interface respectively by inter-mixing effect arising out of mechanical inter-locking. Shear strength of the joint (260 MPa) was quite higher with respect to that of the copper, the weaker metal of the copper-mild steel bimetal combination. Reasonably ductile shear failure occurred in the copper plate, and no failure was observed along the interface.

Fabrication of lamellar porous alumina with regular structure via directional solidification with multiple cold sources

Porous ceramics obtained with aqueous slurries by directional solidification have randomly distributed lamellar pore channels and thus have unstable mechanical properties. According to the anisotropic principle of ice crystal growth, the growth of lamellar ice crystals is regular when multiple cold sources are used, and porous ceramics with regular pore channels are then obtained after drying. Multiple cold sources are formed with a bottom cold plate and copper sides in rectangular molds. The copper sides are in contact with the bottom cold plate, thus forming the side cold source with temperature gradient distribution by heat transfer. The interaction between the side cold source and the bottom cold plate facilitates the regular distribution and continuous growth in parallel of ice crystals. The use of parallel copper sides of the mold results in porous ceramics with an axisymmetric pore structure and high aspect ratios of pore channel in porous alumina. The positive compressive strength of fabricated porous ceramics with an axisymmetric structure is similar with those of conventional directional solidification, but the lateral side direction compressive strength of fabricated porous ceramics with an axisymmetric structure is significantly increased.

Texture Evolution of Nanostructured Aluminum/Copper Composite Produced by the Accumulative Roll Bonding and Folding Process

In this study, the accumulative roll bonding and folding (ARBF) process was used for manufacturing nanostructured aluminum/copper multilayered composites. Textural evolution during the ARBF process of composites was evaluated using X-ray diffraction. Microstructural observation of some samples was evaluated by scanning electron microscopy and transmission electron microscopy. The ARBF process induced formation of a strong preferred orientation along the β-fiber and also to the pronounced copper texture component. In the aluminum side, occurrence of dynamic recovery reduced the intensity of the β-fiber rolling texture due to change in dislocation structure and decrease in the degree of strain hardening. On the other hand, occurrence of discontinuous dynamic recrystallization at the third and fourth ARBF cycles led to decreasing the intensity of fibers and texture components in the copper side. The average grain sizes of the final sample for the copper and aluminum sides were ~50 and ~200 nm, respectively.

Temperature-minimum line in the Cu-Ni-Mn phase diagram

225 The phase diagram of the Cu–Ni–Mn system has been studied for a long time. In Fig. 1, we show iso therms on the liquidus and solidus surfaces of the dia gram established by Parravano in 1913 [1]. Note the temperature minima in the diagrams of the Cu–Mn and Ni–Mn systems, where there are general regions corresponding to solid solutions with a bcc structure on the copper and nickel sides, and the unlimited solubility in the Cu–Ni system. This raises the question of whether there is a contact line of the liquidus and soli dus surfaces in the ternary Cu–Ni–Mn diagram, con necting the minima in the binary Cu–Mn and Ni–Mn diagrams. On that line, there should be a continuous series of ternary alloys solidifying at constant tempera ture, with values ranging from 1020°C (the minimum on the Ni–Mn diagram) to 870°C (the minimum on the Cu–Mn diagram). Nothing has been reported regarding the existence of such a line in metallic systems as yet. Ternary Cu–Ni–Mn alloys with a small control lable temperature range of solidification are encoun tered as solder for use up to 800°C. According to the fundamental texts on physico chemical analysis [1, 2], the isotherms on the ternary Cu–Ni–Mn diagram indicate that the minima in the binary Cu–Mn and Ni–Mn systems are connected along a line running along the liquidus and solidus sur faces of the ternary system. This, in turn, indicates that those surfaces touch along this line. The liquidus and solidus surfaces do not touch in the ternary Cu–Ni–Mn diagram presented in [3]. Verification of the data in [3]—by plotting three dimensional diagrams using 3D Studio Max 9.0 soft ware—indicates that the diagrams and isotherms in [3] are not consistent and, in fact, the liquidus and solidus surfaces do meet along the line connecting the minima in the binary Cu–Mn and Ni–Mn diagrams. It is not a straight line. There are depressions on the liquidus and solidus sur faces of the ternary Cu–Ni–Mn diagram determined by the minima in the binary Cu–Mn and Ni–Mn systems, according to [4]. We conclude that the liquidus and solidus surfaces do not touch on the basis of the ter Temperature Minimum Line in the Cu–Ni–Mn Phase Diagram

Continuous welding of Cu–Ni dissimilar couple using CO2 laser

The evolution of microstructure during continuous laser welding of dissimilar metals has been studied for a binary Cu–Ni couple. The effects of laser beam scan speed and laser power on the shape and size of the melt pool, the weldment–substrate interface, the composition profiles, and microstructures of the weldments have been investigated. It is shown that the melt pools exhibit a characteristic asymmetry in shape. The observed microstructure is characterised by the existence of compositional and microstructural variations leading to a banded appearance suggesting localised mixing. Distinct differences exist in the evolution of the microstructure in the copper and nickel sides of the weld pool. An attempt is made to explain some of the experimental observations using thermodynamic and thermal transport arguments.

Effect of Neutron Irradiation on Mechanical Properties of Cu-Alloy/SS316 Joints

The effects of neutron irradiation on tensile properties of the Cu alloys to type 316 stainless steel (SS316LN-IG) joints fabricated by friction welding method were examined. Additionally, irradiation tests of Al2O3-dispersed copper alloy (Al-25) and SS316LN-IG were conducted. The Al-25/ SS316LN-IG joints were irradiated in the Japan Materials Testing Reactor (JMTR), and tension tests and metallographical observation of these joints have been performed as the post irradiation examination (PIE). In the tension tests of Al-25/SS316LN-IG joints, all irradiated specimens fractured at the copper sides. In the tension tests at 293K, tensile strength of the Al-25/ SS316LN-IG joints irradiated at each temperature was almost similar to that of the base metal (Al-25) irradiated in the same condition. On the other hand, tensile strength of Al-25/ SS316LN-IG joints was smaller than that of Al-25 in the tension tests at the same temperature as each irradiation temperature. In this study, useful data of the irradiated Al-25/ SS316LN-IG joints fabricated by friction welding method were obtained to design fusion reactors.

Spin Density Maps for the Ferrimagnetic Chain Compound MnCu(pba)(H2O)3·2H2O (pba = 1,2-Propylenebis(oxamato)): Polarized Neutron Diffraction and Theoretical Studies

This paper is devoted to the determination of the spin density in the ferrimagnetic ground state of the bimetallic chain compound MnCu(pba)(H2O)(3) . 2H(2)O, with pba = 1,3-propylenebis(oxamato). The crystal structure, previously determined at room temperature through X-ray diffraction, was redetermined at 10 K through unpolarized neutron diffraction (orthorhombic system, space group Pnma, a = 12.727(11) Angstrom, b = 21.352(19) Angstrom, c = 5.153(3) Angstrom, Z = 4). The experimental spin density has been deduced from polarized neutron diffraction data recorded at 10 K under 50 kOe. Positive spin densities were observed on the manganese side and negative spin densities on the copper side. The delocalization of the spin density from the metal centers toward the oxamato bridging ligand was found to be more pronounced on the copper side than on the manganese side, so that the nodal surface (of zero spin density) is closer to manganese than to copper. The experimental spin distribution has been compared to the theoretical distributions deduced from density functional theory (DFT) calculations, using both DGauss and DMol programs. The experimental results for the title chain compound have also been compared to the spin distribution for the binuclear compound [Mn(Me-6-[14]ane-N-4)Cu(oxpn)](CF3SO3)(2) with Me-6-[14]ane-N-4 = (+/-)-5,7,7,12,14,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane, and oxpn = N,N'-bis(3-aminopropyl)oxamido, recently reported. The most striking difference between pair and chain compounds concerns the positive P+ and negative P- spin populations carried by the manganese and copper sides, respectively. For the pair compound P+ was found as 4.67(8) mu(B), and P- as -0.67(8) mu(B) while for the chain compound these values are 5.05(7) mu(B) and -1.05(10) mu(B), respectively. The spin distribution for the ferrimagnetic chain compound is very close to a Neel state (P+ = 5 mu(B) and P- = -1 mu(B)).