Search Results (34)

Electrolytic copper foil is one of the core materials in the fields of electronics, communications, and power. The cathode roller is the key component of the complete set of electrolytic copper foil equipment, and the quality of the titanium cylinder of the cathode roller directly determines the quality of the electrolytic copper foil. There typically exists a longitudinal weld on the surface of the cathode roller’s titanium cylinder sleeve manufactured by the welding method, which leads to the degradation of the quality of the electrolytic copper foil. Refining the grains in the weld zone and the heat-affected zone to close to those of the base material is a key solution for the manufacturing of welded cathode rollers. In order to effectively modify the microstructure and obtain an optimal refining effect in the weld zone of a TA1 cathode roller, a novel composite technology consisting of low-energy and fewer-pass welding combined with multi-pass rolling deformation and vacuum annealing treatment was primarily explored for high-purity TA1 titanium plates in this study. The microstructure of each area of the weld was observed using the DMI-3000M optical microscope, and the hardness was measured using the HVS-30 Vickers hardness tester. The research results show that the microstructure of each area of the weld can be effectively refined by using the novel composite technology of low-energy and fewer-pass welding, multi-pass rolling deformation, and vacuum annealing treatment. Among the explored experimental conditions, the optimal grain refinement effect is obtained with a V-shaped welding groove and four passes of welding with a welding current of 90 A and a voltage of 8–9 V, followed by 11 passes of rolling deformation with a total deformation rate of 45% and, finally, vacuum annealing at 650 °C for 1 h. The grain size grades in the weld zone and the heat-affected zone are close to those of the base material, namely grade 7.5~10, grade 7.5~10, and grade 7.5~10 for the weld zone, heat-affected zone, and base material, respectively. Meanwhile, this technology can also refine the grains of the base material, which is conducive to improving the overall mechanical properties of the titanium plate. Full article

This study presents the characteristics of the Ti-33Mo-0.2C alloy, which belongs to the group of titanium alloys with a stable β phase and contains 0.27 wt% carbon; this is significantly higher than the permissible level for this alloy, which is 0.1 wt%. The Ti-33Mo-0.2C alloy was melted in a vacuum induction furnace with a cold copper crucible and subsequently processed into a 12 mm diameter rod through hot rolling and annealing under standard conditions. The microstructure, as well as the mechanical and physicochemical properties of the Ti-33Mo-0.2C alloy, were compared with those of the Ti-33Mo alloy of a similar chemical composition. The following techniques were used to characterize the microstructure and properties of the alloys: LM; SEM/EDS (WDS); XRD; and mechanical, creep, and corrosion testing. The conducted analyses demonstrated that the addition of approximately 0.2 wt% carbon to the Ti-33Mo alloy leads to the expected improvement in microstructural stability by reducing grain growth and inhibiting the precipitation of the α phase at β grain boundaries. Consequently, a unique simultaneous enhancement of both strength and ductility, with increased creep resistance, is observed while maintaining the excellent corrosion resistance of the investigated alloy. The observed beneficial effects and additional capabilities resulting from the presence of carbon in the investigated alloy justify the conclusion that carbon should no longer be regarded as an undesirable impurity, which stands in contrast to some previous statements. Full article

Annealing and rolling play critical roles in improving the mechanical properties of arc spraying coatings. In this work, we successfully fabricated copper–steel bimetallic sheets (CSBSs) using an arc spray-rolling short process and achieved excellent internal bonding of the copper coating and improved deep-drawing of the CSBSs via annealing and rolling synergistic treatment. The results indicate that the microstructure of the copper coating became dense, and the porosity effectively reduced after annealing–rolling–annealing (ARA) treatment. Tight bonding was also observed between the copper coating and steel substrate. The copper coating had a porosity of less than 0.2%, an average grain size of 3.8 μm, and a micro-hardness of 55 HV_0.05. After tensile testing, the As-sprayed coating generated brittle fractures and delamination. The A-R-A coating also displayed elongated dimples, with the majority oriented along the TD direction, and bonded well with the steel substrate. In addition, the As-sprayed coating fell off directly after deep drawing. In contrast, the A-R-A coating did not exhibit cracks and fall off. The fracture mechanism gradually changed from falling off and cracking, to toughness deformation due to the reduced porosity and tighter grain boundaries, and finally to cooperative deformation due to the metallurgical bonding of the sprayed particles and good interface bonding properties. These findings provide guidance and reference for the practical application of thermal spray additive manufacturing. Full article

This study investigates the characteristics of the Ti-5Al-2.5Sn-0.2C alloy, an alpha titanium alloy containing approximately 0.2 wt% carbon—a concentration significantly exceeding the standard allowable limit of 0.08 wt%. The Ti-5Al-2.5Sn-0.2C alloy was melted in a vacuum induction furnace with a cold copper crucible, processed into bar form through hot rolling, and subsequently annealed under standard conditions. The microstructure and mechanical properties of the Ti-5Al-2.5Sn-0.2C alloy were systematically compared with those of the Ti-5Al-2.5Sn alloy (Grade 6), which possesses a similar chemical composition. The results revealed that the addition of 0.2 wt% carbon significantly influences the alloy’s solidification process, phase transformation temperatures, phase composition, and phase lattice parameters. Moreover, the carbon addition enhances key mechanical properties, including tensile strength, yield strength, hardness, and wear resistance, as well as creep and oxidation resistance. While a slight reduction in plasticity and increase in impact energy were observed, the alloy remained within the permissible range defined by existing standards. Full article

This study achieved the successful creation of a 6061/M21/6061 composite sheet, with Cu powder incorporated in the middle, through a two-pass hot roll bonding process. The effect of Cu powder addition on interface microstructure evolution of Mg-Al composite plate during annealing was studied. The results show that the incorporation of copper powder significantly suppresses the formation of Mg-Al intermetallic compounds (IMCs) at the boundary of Al-Mg bonded plates. The IMCs’ thickness of composite plate Mg-Al interface absent Cu powder increased from 7.0 µm at 250 °C to 61.2 µm at 400 °C, showing a rapid growth trend. On the contrary, in the area with Cu powder of composite plate containing Cu powder, when the temperature ranges from 250 °C to 350 °C, the Mg-Al diffusion layer is thin and only varies between 1 µm and 3.2 µm and, even when the temperature rises to 400 °C, the diffusion layer is only 18.8 µm. At a constant temperature, the diffusion rate of IMCs in the Cu powder-containing region of the composite plate is significantly lower than that in the region without Cu powder. Upon the addition of Cu powder, Al₂Cu and Al_0.92Cu_1.08Mg phases are formed, which decrease the proportion of the brittle phases Al₃Mg₂ and Mg₁₇Al₁₂ at the composite plate interface, thereby effectively mitigating the diffusion of IMCs within the Mg-Al interface. This presents a novel concept for the investigation of enhanced interface bonding and the fabrication of Mg-Al composite plates. Full article

Fe–Ni–Co–Al-based systems have attracted a lot of interest due to their large recoverable strain. In this study, the microstructure and thermal cycling behaviors of Fe₄₁Ni₂₈Co₁₇Al_11.5Ti_1.25Nb_1.25 (at.%) 98.5% cold-rolled alloys after annealing treatment at 1277 °C for 1 h, followed by aging for 48 h at 600 °C, were investigated. From the electron backscatter diffraction results, we see that the texture intensity increased from 9.4 to 16.5 mud and the average grain size increased from 300 to 400 μm as the annealing time increased from 0.5 h to 1 h. The hardness results for different aging heat treatment conditions show the maximum value was reached for samples aged at 600 °C for 48 h (peak aging condition). The orientation distribution functions (ODFs) displayed by Goss, brass, and copper were the main textural features in the FeNiCoAlTiNb cold-rolled alloy. After annealing, strong Goss and brass textures were formed. The transmission electron microscopy (TEM) results show that the precipitate size was ~10 nm. The X-ray diffraction (XRD) results show a strong peak in the (111) and (200) planes of the austenite (⁠⁠γ, FCC) structure for the annealed sample. After aging, a new peak in the (111) plane of the precipitate (⁠⁠γ′, L12) structure emerged, and the peak intensity of austenite (⁠⁠γ, FCC) decreased. The magnetization–temperature curves of the aged sample show that both the magnetization and transformation temperature increased with the increasing magnetic fields. The shape memory properties show a fully recoverable strain of up to 2% at 400 MPa stress produced in the three-point bending test. However, the experimental recoverable strain values were lower than the theoretical values, possibly due to the fact that the volume fraction of the low-angle grain boundary (LABs) was small compared to the reported values (60%), and it was insufficient to suppress the beta phases. The beta phases made the grain boundaries brittle and deteriorated the ductility. On the fracture surface of samples after the three-point bending test, the fracture spread along the grain boundary, and the cross-section microstructural results show that the faces of the grain boundary were smooth, indicating that the grain boundary was brittle with an intergranular fracture. Full article

Commercial oxygen-free copper sheets were cold-rolled with reduction rates ranging from 20% to 87% and annealed at 400, 500 and 600 °C. The microstructure and texture evolution during the cold-rolling and annealing processes were studied using optical microscopy (OM), scanning electron microscopy (SEM) and electron back-scattered diffraction (EBSD). The results show that the deformation textures of {123}<634> (S), {112}<111> (Copper) and {110}<112> (Brass) were continuously enhanced with the increase in cold-rolling reduction. The orientations along the α-oriented fiber converged towards Brass, and the orientation density of β fiber obviously increased when the rolling reduction exceeded 60%. The recrystallization texture was significantly affected by the cold-rolling reduction. After 60% cold-rolling reduction, Copper and S texture components gradually decreased, and the {011}<511> recrystallization texture component formed with the increase in annealing temperature. After 87% cold-rolling reduction, a strong Cube texture formed, and other textures were inhibited with the increase in annealing temperature. The strong Brass and S deformation texture was conducive to the formation of a strong Cube annealing texture. The density of the annealing twin boundary decreased with the increase in annealing temperature, and more annealing twin boundaries formed in the oxygen-free copper sheets with the increase in cold-rolling reduction. Full article

The factors that influence the formation of helium blisters in copper were studied, including crystallographic grain orientation and thermomechanical conditions. Helium implantation experiments were conducted at 40 KeV with a dose of 5 × 10¹⁷ ions/cm², and the samples were then subjected to post-implantation heat treatments at 450 °C for different holding times. A scanning electron microscope (SEM) equipped with an electron backscatter diffraction (EBSD) detector was used to analyze the samples, revealing that the degree of blistering erosion and its evolution with time varied with the crystallographic plane of the free surface in different ways in annealed and cold rolled copper. Out of the investigated states, rolled copper with a (111) free surface had superior helium blistering durability. This is explained by the consideration of the multivariable situation, including the role of dislocations and vacancies. For future plasma-facing component (PFC) candidate material, similar research should be conducted in order to find the optimal combination of material properties for helium blistering durability. In the case of Cu selection as a PFC, the two practical approaches to obtain the preferred (111) orientation are cold rolling and thin layer technologies. Full article

This article investigated the formability of aluminum/copper bimetal sheets during single-point incremental forming. First, the two-layer sheets were produced by the explosive welding process; then, the rolling process was performed with 50% strain on two-layer samples. Considering the importance of examining the mechanical and metallurgical properties on the formability of the two-layer samples, the mechanical properties were first examined, including the uniaxial tensile and micro-hardness tests. Then, metallurgical tests were performed, including scanning electron microscopy equipped with energy-dispersive X-ray spectroscopy (SEM-EDX) to investigate the fracture surface and penetration depth and an X-ray diffraction (XRD) test to check the secondary phase particles in the penetration zone of Al and Cu in five different annealing temperature conditions. Considering that the forming limit diagram (FLD) is dependent on the strain path, to study the effect of the strain path, the two-layer samples were formed by three geometries: pyramid, cone, and straight groove. Simulations of FLD by Abaqus software 6.14-4 with four different methods were studied: FLD_CRT, effective strain rate (ESR), second derivation of thinning (SDT), and maximum strain rate (MSR). The results showed that the FLD_CRT criterion provided a more accurate estimate of the necking time. In the following, the values of the thickness distribution were carried out by experimental and numerical methods, and the results between the methods were in good agreement. Full article

Copper and its alloys are structural materials used in industries and engineering applications due to their excellent thermal and electrical conductivity and chemical stability. Integrating graphene, known for its exceptional electrical conductivity, into the copper matrix is a promising strategy to enhance mechanical properties without sacrificing electrical conductivity. The Accumulative Roll Bonding (ARB) process can effectively and homogeneously introduce graphene into the metal matrix and is adaptable to an industrial scale. This study investigates the impact of varying graphene concentrations and two heat treatment protocols (without a controlled atmosphere) on the mechanical and electrical properties of ARBed copper/graphene composites. Optical microscopy revealed minimal voids and graphene clumps, and the energy dispersive spectroscopy analysis revealed the absence of copper oxide in some samples. The conductivity test showed little influence of the graphene content and stress relief heat treatment temperature on electrical conductivity (~86% of the International Annealed Copper Standard) within a limited number of ARB cycles. The tensile tests did not reveal a significant influence of the graphene content and stress relief heat treatment temperature on the ultimate tensile strength (220–420 MPa) and elongation (~2%). Full article

An Al-Fe alloy which was produced by hot extrusion of rapidly solidified powder is a possible solution to substitute copper-based electrical conductor material due to its high strength and high electrical conductivity. However, the stress relaxation characteristic—an essential parameter as a conductor material—and the effect of the material structure have not been reported, which was the aim of the present paper. An Al-5%Fe alloy was selected as the test material. The material structures were controlled by hot extrusion practice, annealing, and cold rolling. The Al-Fe intermetallic compound particles controlled the residual stress after the stress relaxation test via the Orowan mechanism. Decreasing the mean inter-particle distance reduces the electrical conductivity. The increase in the number of dislocations by the cold rolling increased strength at room temperature without changing electrical conductivity; however, it did not have a positive effect on the stress relaxation characteristics. The stress relaxation characteristics and the electrical conductivity of the Al-Fe alloy were superior to conventional C52100 H04 phosphor bronze when compared with the case of the same mass. Full article

In this paper, Cu-6 wt%Ag alloy sheets were prepared using vacuum induction melting, heat treatment, and cold working rolling. We investigated the influence of the aging cooling rate on the microstructure and properties of Cu-6 wt%Ag alloy sheets. By reducing the cooling rate of the aging treatment, the mechanical properties of the cold-rolled Cu-6 wt%Ag alloy sheets were improved. The cold-rolled Cu-6 wt%Ag alloy sheet achieves a tensile strength of 1003 MPa and an electrical conductivity of 75% IACS (International Annealing Copper Standard), which is superior to the alloy fabricated with other methods. SEM characterization shows that the change in properties of the Cu-6 wt%Ag alloy sheets with the same deformation is due to a precipitation of the nano-Ag phase. The high-performance Cu-Ag sheets are expected to be used as Bitter disks for water-cooled high-field magnets. Full article

Single-crystal planes are ideal platforms for catalytic research. In this work, rolled copper foils with predominantly (220) planes were used as the starting material. By using temperature gradient annealing, which caused grain recrystallization in the foils, they were transformed to those with (200) planes. In acidic solution, the overpotential of such a foil (10 mA cm⁻²) was found to be 136 mV lower than that of a similar rolled copper foil. The calculation results show that hollow sites formed on the (200) plane have the highest hydrogen adsorption energy and are active centers for hydrogen evolution. Thus, this work clarifies the catalytic activity of specific sites on the copper surface and demonstrates the critical role of surface engineering in designing catalytic properties. Full article

Levels of lead (Pb) in tap water that are well below established guidelines are now considered harmful, so the detection of sub-parts-per-billion (ppb) Pb levels is crucial. In this work, we developed a two-step, facile, and inexpensive fabrication approach that involves direct bonding of copper (Cu) and liquid crystal polymer (LCP) followed by polyester resin printing for masking onto Cu/LCP to fabricate Cu thin-film-based Pb sensors. The oxygen plasma-treated surfaces resulted in strongly bonded Cu/LCP with a high peel strength of 500 N/m due to the highly hydrophilic nature of both surfaces. The bonded specimen can withstand wet etching of the electrode and can address delamination of the electrode for prolonged use in application environments. The Cu-foil-based electrochemical sensor showed sensitivity of ~11 nA/ppb/cm² and a limit of detection (LOD) of 0.2 ppb (0.2 µg/L) Pb ions in water. The sensor required only 30 s and a 100 µL sample to detect Pb. To date, this is the most rapid detection of Pb performed using an all-Cu-based sensor. The selectivity test of Cu to Pb with interferences from cadmium and zinc showed that their peaks were separated by a few hundred millivolts. This approach has strong potential towards realizing low-cost, highly reliable integrated water quality monitoring systems. Full article

Copper alloys with chromium, hafnium, and scandium combining enhanced strength as well as high electrical and thermal conductivity are analyzed in depth. The aim is to compare the precipitation process during temperature exposure to meet increasing material requirements. This research focuses on alloying elements having a limited, maximum 1 wt.%, and with temperature decreasing solubility in copper. For the simultaneous enhancement of mechanical strength and conductivity, precipitation hardening is the utilized mechanism during the processing of as-casted annealed and quenched specimens and in combination with optional cold-rolling prior to the aging process. Extensive DSC measurements, accompanied by metallographic investigations, and the analysis of hardness and electrical conductivity, lead to a versatile description and comparison of different alloying systems. CuCr0.7 starts to precipitate early and is mainly influenced by the temperature of aging. Provoking the solid solution with cold deformation has a less significant influence on the following precipitation. CuSc0.3 and CuHf0.7 precipitate at higher temperatures and are highly influenced by cold deformation prior to aging. Furthermore, CuHf0.7 and CuSc0.3 show advantages regarding the recrystallization behavior, making them especially applicable for higher operating temperatures. Future research will assess ternary alloy combinations to further scoop the potential. Full article