Search

This paper comprehensively reviews friction stir welding (FSW) as applied to copper and its alloys. FSW is a solid-state joining process that offers significant advantages over traditional fusion welding methods, particularly for materials like copper that are difficult to weld conventionally due to their high thermal conductivity and oxidation issues. Over time, the FSW process has been developed for different industries. Copper structures joined through FSW are utilized for nuclear waste storage, electrical connectors, chemical and petrochemical storage, refrigeration systems, heat exchangers, and the aerospace industry. This covers recent advancements in FSW technology, the geometry of the tools used, the process parameters, and the microstructural characteristics and mechanical properties of the joints. It examines the shapes, sizes, and materials of the tools used for welding copper and its alloys, along with process parameters such as rotational speed and traverse speed, and their influence on the quality of the joints. Additionally, the paper presents syntheses of previously published results, highlighting the values of parameters that indicate the quality of the welds, including grain size, microhardness, mechanical strength, and elongation. The challenges and potential solutions in applying FSW to copper are also discussed, providing a starting point for future research and industrial applications. [ABSTRACT FROM AUTHOR]

Long-term corrosion behaviors of copper-zinc alloy (H62) and copper-nickel alloy (B30) in a typical marine atmospheric environment are systemically investigated in this work. Microstructural characterization and electrochemical tests show that pitting corrosion occurs on H62 alloy, and the bottom of the pits is dendritic due to preferential dezincification, whereas B30 exhibits uniform corrosion with a relatively compact corrosion product after long-term exposure. The outermost and innermost layers (accounting for 9.7% and 43.8% of the entire thickness of the corrosion products, respectively) with copper enrichment exist on B30, and the middle layer is enriched with nickel oxide. The annual weight loss rate for H62 is 1.5 times larger than for B30 (approximately 4.65 g m−2 y−1), indicating an improved corrosion resistance for the nickel addition compared to zinc. Furthermore, the Warburg impedance across the corrosion pits increases with the exposure period for H62 alloy due to the slower oxygen or soluble ion diffusion therein, which demonstrates that the pit growth becomes slow as the corrosion products thicken before re-passivation. [ABSTRACT FROM AUTHOR]

The unconventional wire electrical discharge machining (WEDM) technology represents a vital manufacturing technology in different industrial branches, such as aviation, military, automotive or energy industry. The WEDM energy demand is considerable and it is, therefore, desirable to reduce the machining time by optimising the machining parameters. In the study, the chosen parameters were Pulse off time, Gap voltage, Discharge current, Pulse on time, and Wire feed. Another factor we investigated in our Box-Behnken design of the experiment was the workpiece thickness. The cutting speed, topography, and surface morphology were analysed in the samples produced for the design of the experiment. This investigation was carried out using electron microscopy. The chemical composition of individual spots was analysed as well. The samples were found not to have significant differences in the appearance of craters on the edge and in the centre. Similarly, there was no significant difference observed between thicknesses and different parameter settings. The surfaces also show a large number of small bubbles. There were, however, no cracks or other defects found, even in the cross-sections of all samples. [ABSTRACT FROM AUTHOR]

The objective of this study was to develop an artificial neural network (ANN) model for predicting the tensile strength of friction stir welding (FSW) joints between dissimilar materials, with a particular focus on aluminum and copper, using cryogenic processes. The research addresses the challenges posed by differences in material properties and the complex nature of FSW, where traditional experimental methods are time-consuming and costly. FSW experiments were conducted under a variety of conditions, and the resulting temperature data were utilized as input for a heat transfer analysis. The maximum temperature and temperature gradient obtained from the analysis were employed as input variables for training the ANN. The ANN was optimized using the Hyperband tuner and validated against experimental results. The model successfully predicted tensile strength with an average error of 5.4%, demonstrating its potential for predicting mechanical properties under different welding conditions. This approach offers a more efficient and accurate method for optimizing FSW processes. [ABSTRACT FROM AUTHOR]

Copper-based alloys are widely known for their high thermal and electrical conductivity. Although the use of these alloys in powder-based additive manufacturing (AM) shows significant promise, applying this method in wire arc additive manufacturing (WAAM) processes poses various considerable challenges, including porosity, delamination, surface oxidation, etc. The limited research on WAAM of copper alloys, especially Cu1897, highlights the need for a more in-depth investigation. This study addresses the effects of process parameters in pulse cold metal transfer (CMT)-based WAAM of Cu1897, i.e., pulse correction (PC) and arc length correction (ALC), on bead penetration and porosity. The results showed that as PC was increased from −5 to +5, weld bead penetration increased from 2.38 mm to 3.87 mm. To further enhance penetration and reduce the porosity, the ALC was varied from +30% to −30% with a step size of 15%. The results showed that weld bead penetration increased to 4.47 mm by altering the ALC from +30% to −30%. Additionally, as the ALC varied within this range, porosity decreased significantly from 3.98% to 0.28%. Overall, it is concluded that a lower value of ALC is recommended to improve bead penetration and reduce porosity in WAAM of Cu1897. [ABSTRACT FROM AUTHOR]

Purpose: This paper aims to enhance lubrication performance of the pitcher plant–like textured surface with various parameters. Design/methodology/approach: A pitcher plant–like structure surface is fabricated on the copper alloy, and the lubrication performance of the pitcher plant–like structure with various parameters is evaluated. In addition, the pressure distribution and oil film load capacity of the pitcher plant–like surface are simulated based on Navier–Stokes equations. Findings: When the direction of motion aligns with the pitcher plant–like structure, the friction coefficient remains lower than that of the nontextured surface, and it exhibits a decreasing trend with the increasing of the texture width and spacing distance; the lowest friction coefficient (0.04) is achieved with B = 0.3 mm, L = 1.0 mm and θ = 45°, marking a 75% reduction compared to the nontextured surface. Simulation results demonstrate that with the increase in texture width and spacing distance, the oil film load-bearing capacity demonstrates an increasing trend. Originality/value: Bionic pitcher plants are prepared on the copper alloy to improve the lubrication performance and wear resistance. Peer review: The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-04-2024-0119/ [ABSTRACT FROM AUTHOR]

The effect of copper addition, solution heat treatment and aging on Al-Zn-Mg alloy's microstructure, mechanical and thermal properties is studied using an optical microscope (O.M.), scanning electron microscope (SEM), X-ray diffractometer (XRD), Micro-Vickers hardness, universal tensile machine (UTM) and differential scanning calorimetry (DSC). Al-Zn-Mg-xCu (0.02 wt% and 0.89 wt%) alloys are made using 5754 alloys, pure zinc and Al-Cu alloy. After casting, Al-Zn-Mg-xCu (0.02 wt% and 0.89 wt%) alloys are heat-treated in a solution (480 °C for 1 h). After solution heat treatment, aging (180 °C for 10 to 60 minutes) is applied. As-cast Al-Zn-Mg-xCu (0.02 wt% and 0.89 wt%) alloys contain η (MgZn2) phase and T (Al2Mg3Zn3) phase. After solution heat treatment, the η and T phase dissolves into a supersaturated solid solution. Adding copper into Al-Zn-Mg alloys increases hardness from 115.94 to 135.22 HV1. Solution heat treatment improves the hardness and strength due to the dissolution of precipitate phases and the formation of solid solution atoms. Aging improves hardness due to the formation of coherent G.P. zones. Adding copper decreases the precipitate phase's dissolution temperature from 472.2 to 468.6 °C. [ABSTRACT FROM AUTHOR]

In this research paper, the effect of the addition of copper (0.02 to 3.32 wt.%) on microstructure, mechanical and thermal properties of Al-Zn-Mg alloy are studied using an optical microscope, scanning electron microscope (SEM), X-ray diffractometer (XRD), Vicker's microhardness tester, universal testing machine (UTM) and differential scanning calorimeter (DSC). Precipitates (η-MgZn2 phases) are present in as-cast Al-Zn-Mg alloy. SEM and XRD analyses have shown the presence of η (MgZn2) and θ (Al2Cu) precipitate in the as-cast Al-Zn-Mg-Cu alloy. Micro-Vickers hardness increases from 121.3 HV1 to 153.1 HV1 for the initial increase in copper content (0.02 to 1.54 wt.%) and then decreases to 137.3 HV1 (3.32 wt.% copper). The melting point decreases continuously with increased copper content from 619.8 °C (0.02 wt.% Cu) to 608.5 °C (3.32 wt.% Cu). Peak compressive stress, absorbed energy per unit volume, yield stress is observed to increase by 43.6%, 75.4%, and 59.3%, respectively, for the rise in copper content (0.02 wt.% to 1.54 wt.%) in the alloy. [ABSTRACT FROM AUTHOR]

This paper presents a critical review of the reasons behind the initiation of this project to find a more sustainable, cost efficient, and safer form of chloride extraction that would result in stabilisation of archaeological copper and its alloys with tin and zinc. The imperative has become increasingly strident with cutbacks in funding for museum conservation facilities and with the reduction in staff, leaving less time for routine analyses of traditional immersive washing treatments that could take several years to effect. Owing to the faster oxidation and reduction kinetics of copper, compared with tin and zinc ions, the problems of uncontrolled corrosion of copper alloys in a chloride-rich environment have led to unacceptable levels of decay in heritage collection items. This study looked at the chloride extraction rates under subcritical conditions for both primary and secondary chloride-rich mineral species nantokite, clinoatacamite, and atacamite and determined the impact of changing the solution pH from 8 to 10, while also addressing the impact of temperature. The range of temperatures between 130 and 230°C was assessed at 50°C intervals at both levels of acidity of the leaching liquors. For the nantokite treatment, the formation of a cuprite patina which replaced the waxy-grey initial corrosion products was regarded as a bonus. The nature of the patina and changes in surface textures resulting from the treatment are critically reviewed and a series of recommendations for future work are included in the conclusion. [ABSTRACT FROM AUTHOR]

Overcoming the strength‐ductility trade‐off in metals and alloys entails the optimization of the compositions and dedicated microstructural design, which remains experimentally laborious and challenging. Here, a combinatorial method is devised to construct a Cu‐Ti alloy library encompassing diverse compositions, microstructures, and mechanical properties, allowing to efficiently identify a copper alloy with an unprecedented yield strength of 3.8 GPa and high deformability. The exceptional properties are attributed to a crystal‐glass nano‐heterostructure (CGNH) consisting of nanograins, nano twins, and glassy phases. Ultrahigh strength stems from the extreme strengthening of structural‐unit refinement and the avoidance of softening caused by grain‐boundary sliding through the inclusion of glassy phases between nanograins. Remarkable deformability is associated with the activation of homogeneous flow in nanosized glassy phases, complemented by coordinated nanocrystal rotation. The CGNH architecture offers a potent route to overcome the trade‐off between alloy strength and deformability. [ABSTRACT FROM AUTHOR]

The case study addresses the question of the early medieval revival of copper production in Europe. The focus of the research area is the Carpathian Basin, located on the eastern periphery of the zone influenced by European early medieval processes. The research of where and when early medieval metal production started in the region in our case also provides answers to the question of how the region was linked to the European continental economic network, which is until recently an unresolved problem. Ore extraction and the production of various non-ferrous metals (copper, silver, gold) had important centres in the Carpathian Mountains throughout the Middle Ages until the Modern Era. Concerning the Avar period, our study comprises lead isotope and chemical analyses of 'Late Avar' (c. 8th century AD) copper rivets, used for certain purposes alongside the copper alloys predominant in the period. As rivets were selected from the entire Avar cultural area, expanding virtually to all lowland and hilly areas in the Carpathian Basin, results are representative of the entire region. It shows that Avar craftsmen producing large quantities of copper alloy objects in the 8th and the early 9th century were supplied with copper from a single mining district, from the ore deposits of the Slovak Ore Mountains in the today Central Slovakia, a region which became an important metal-processing centre in the 11th century AD. [ABSTRACT FROM AUTHOR]

Although low mechanical properties, Zinc (Zn) alloy systems with Copper (Cu) and Silver (Ag) as alloying elements have strong biocompatibility and biodegradability characteristics. This study examined the effects of rolling parameters and Ag alloying on the mechanical, biodegradable, and final structure of an alloy based on Zn. Comparing treated and untreated specimens, the addition of Ag led to a considerable improvement in both hardness and compressive strength. The produced alloys with varying amounts of Ag (between 1 and 4 wt%) were cold rolled at 400–800 r/min and friction coefficients between 0.3 and 0.5. The alloys' ultimate strength rose with an increase in rolling speed for Zn1Cu4Ag, and hardness and compressive strengths rose to 80HV and 470 MPa, respectively. It was demonstrated that rolling force rose somewhat with Ag concentration but significantly increased with rolling speed and friction. E. Coli and S. aureus were used to assess the biodegradable alloys' antibacterial properties. For the Zn-1Cu-2Ag alloy, the inclusion of Ag resulted in a considerable (50%) rise in antibacterial activity that exceeded the effects seen in other alloy systems. [ABSTRACT FROM AUTHOR]

Three-dimensional scanning techniques are being more frequently used in modern industry, especially for quality control. This study shows the possibility of implementing 3D scanning as a tool for assessing the abrasion resistance of non-ferrous metal and alloy cast rods obtained in the continuous casting process. Samples of the same diameter after preweighing and initial scanning were subjected to abrasion tests in five identical cycles to show the progress of their wear. To conduct this process, the samples were weighed and scanned after each cycle. After the final abrasion test, the pure aluminum weight loss was 7%, with 3.4–4.1 mm abrasion, while the AlSi alloy had a weight loss of only 4.63% and 2.3–2.4 mm abrasion. When it came to pure copper, the loss was 2.76%, with 1.6–1.7 mm abrasion. CuNiSi alloys showed a loss between 2.01% and 2.24% and 1.3–1.5 mm abrasion, while CuMg alloys showed a loss between 1.51% and 1.63% and 1.2–1.4 mm abrasion, depending on the Ni and Mg content, respectively. The obtained results were correlated with the density and hardness of the tested materials and proved that both these factors are relevant when it comes to abrasion resistance; however, hardness is more significant. [ABSTRACT FROM AUTHOR]

The copper alloy components are produced using the process of thixotropic extrusion and subsequently subjected to annealing at temperatures ranging from 500 °C to 600 °C for 2 hours. The liquids islands exist inside the solid phases, and the primary phases consist of α-Cu, Cu41Sn11, and Cu3P phases of thixotropic extruded copper alloy. The average grain size initially declines and subsequently increases as the annealing temperature rises. The segregation is improved, and the average grain size is fined of thixotropic extruded copper alloy by annealing at 550 °C for 2h. The impact of texture on mechanical properties can be ignored due to negligible preferred orientation is formed following annealing. The tensile strength and elongation of thixotropic extruded copper alloy are improved after annealing at 550 °C for 2h, resulting in the highest values of 449.8 MPa and 19 pct, respectively. [ABSTRACT FROM AUTHOR]

In the field of petroleum extraction, the welding technology of the core wire (the hybrid structure of copper and the Ni-Cr alloy) in high-power oilfield heaters is a key process that determines the efficiency of the heater. Using the tungsten inert gas (TIG) welding method of filling pure copper wire, this work effectively joins the dissimilar metals of red copper and the Cr20Ni80 nickel–chromium alloy. The microstructure, mechanical properties, and conductivity of the joint were analyzed. The results showed that the surface of the welded dissimilar metal joint was smooth and uniform; radiographic nondestructive testing did not reveal any macroscopic forming defects such as pores or cracks. The microstructure of the joint fusion zone exhibits an equiaxed grain morphology. The interface between the copper and the fusion zone displays a columnar grain structure, growing perpendicular to the fusion line. An interdiffusion layer of elements was formed at the interface between the Ni-Cr alloy and the fusion zone. The microhardness of the joint shows a stepwise decreasing trend, with the highest hardness on the nickel–chromium alloy side, followed by the fusion zone, and the lowest on the copper side. The joint fractures at the copper base material, with a tensile strength greater than 220 MPa, indicating a ductile fracture mode. During the electrical heating process, the joint temperature does not significantly increase compared to the copper side, demonstrating good thermal stability. [ABSTRACT FROM AUTHOR]

Copyright of Metal Working (1674-165X) is the property of Metal Working Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Various ratios of CuPd alloy are loaded on C3N4 and utilized as efficient photocatalyst for the light‐switched homo‐coupling of alkynes in anaerobic and base free condition. For the model phenylacetylene reactant, the light‐irradiation promotes the reaction rate from 36.9 % to 99.9 % and the selectivity of 1,3‐diynes from 0 % to 68.7 %. Different supports, solvents and the induction period of the prepared samples show influence on the activity. The action spectra with different light wavelengths demonstrate that both copper phenylacetylide intermediate formed during the reaction and the localized surface plasmon resonance (LSPR) effect of the copper in CuPd alloy are the photoactive species. Through the control experiments, it confirms that these dual photoactive species and the interface between Cu and Pd are essential for efficient light‐switching reaction pathway. [ABSTRACT FROM AUTHOR]

Laser beam welding is the most modern and promising process for the automatic or robotized welding of structures of the highest Execution Class, EXC3-4, which are made of a variety of weldable structural materials, mainly steel, titanium, and nickel alloys, but also a limited range of aluminum, magnesium, and copper alloys, reactive materials, and even thermoplastics. This paper presents a systematic review and analysis of the author's research results, research articles, industrial catalogs, technical notes, etc., regarding laser beam welding (LBW) and laser hybrid welding (LHW) processes. Examples of industrial applications of the melt-in-mode and keyhole-mode laser welding techniques for low-alloy and high-alloy steel joints are analyzed. The influence of basic LBW and LHW parameters on the quality of welded joints proves that the laser beam power, welding speed, and Gas Metal Arc (GMA) welding current firmly decide the quality of welded joints. A brief review of the artificial intelligence (AI)-supported online quality-monitoring systems for LBW and LHW processes indicates the decisive influence on the quality control of welded joints. [ABSTRACT FROM AUTHOR]

In 2009, during research of a cemetery of the Wielbark culture in Czarnówko (Lębork District, Pomerania), an inhumation grave was discovered, which contained the remains of a wooden bowl with copper alloy fittings. Inside it, several hazelnuts were preserved. This vessel, in the light of the analysis carried out, was made of alder wood using a turning technique. Discoveries of this type are not only rare in the area of the Wielbark culture, but also in the rest of Central European Barbaricum. This article presents the results of the archaeobotanical research and demonstrates the bowl in the broader context of Roman Period discoveries. [ABSTRACT FROM AUTHOR]

The interrelation of the structure and tribomechanical characteristics of the metal materials that comprise the friction members is considered, specifically the interactions between copper alloy – steel and steel with Cu – Zn coatings – steel. The formation of a wear-resistant structural state in the operational layer of Cu – Zn alloys with concentrations of up to 93% of Zn is described. The tribomechanical efficiency of Cu – Zn coatings obtained by two methods is considered from the standpoint of the regularities of the formation of a wear-resistant structure, namely friction-mechanical treatment and cold gas-dynamic spraying. It is demonstrated that regardless of the technology used for the surface modification of a steel product with a copper-based alloy, a secondary self-organizing structure with parameters characteristic of the wear-resistant state is formed in the operational layer as a result of contact deformation, which ensures an increase in the durability of tribological contacts. [ABSTRACT FROM AUTHOR]

Copyright of Stratum Plus Journal is the property of P.P. Stratum plus and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

According to the state of the art, most of the mixed copper and copper alloy scrap and residues are processed in a copper smelter. Despite the environmental and economic advantages relative to primary production, the recycling of copper and its alloying elements (zinc, tin, lead, nickel, etc.) requires significantly more energy and cost than remelting unmixed or pure scrap fractions such as separate collected material or production scrap. To date, however, less attention has been given to the mechanical purification of mixed scrap. Therefore, sorting by alloy-specific components (SBASC) using an industrial X-ray fluorescence (XRF) sorting system was tested on the coarse metallic fraction (10–32 mm) of mixed foundry residues. The findings show that XRF–SBASC can recover higher-grade copper concentrates (reaching 98.3% Cu), leaded brass and complex alloys, such as aluminium bronze and red brass with high purities, for the use in the production of new materials. XRF–SBASC can therefore contribute to a more resource efficient metal recycling, mainly by reducing the energy consumption and loss levels in copper metallurgy. [ABSTRACT FROM AUTHOR]

The phase equilibria of the Cu–Ti–V system were investigated via key experiments coupled with thermodynamic modeling. The isothermal sections at 600 °C, 700 °C, and 800 °C were constructed using X-ray diffraction (XRD) and scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM/EDS). The solubilities of Cu in the (βTi, V) phase and V in intermediate phases Cu4Ti, Cu3Ti2, Cu4Ti3, CuTi, CuTi2, and CuTi3 were determined. Based on the thermodynamic descriptions of three binary subsystems and the experimental data, the thermodynamic assessment of the Cu–Ti–V system was carried out by means of the CALPHAD (CALculation of PHAse Diagrams) method. A set of thermodynamic parameters for the Cu–Ti–V system was obtained and the calculated phase equilibria were consistent with the experimental results. The liquidus projection and the reaction scheme of the Cu–Ti–V system were constructed. This work provides important phase equilibria and thermodynamic data for the composition and process design of new copper alloys. [ABSTRACT FROM AUTHOR]

The wear and friction characteristics of the CuSn10P1 copper alloy are influenced by various factors, including the sliding velocity and applied force. An investigation has been conducted to examine the influence of various loads and sliding velocities on the wear characteristics of the thixoextruded copper alloy. The annealed alloy exhibits a homogeneous distribution of the solid phase, and a liquid island presents in the solid phase. The major phases consist of α-Cu, Cu41Sn11, and a few Cu3P phases. The average coefficient of friction (COF) is between 0.6 and 1.0. SEM-EDS and three-dimensional topography instruments were used to analyze the surface topography and wear rate of reciprocating wear. When the sliding velocity was 5 mm/s, the wear rate increases from 0.07 mm3/Nm to 0.226 mm3/Nm as the load increases from 3 N to 9 N, in accordance with Archard's dry wear law. The worn surface exhibited groove, granular, and layered debris, and the predominant characteristics of the wear were abrasive wear and delamination wear. As the load increased, there was a transition from abrasive wear to delamination wear. [ABSTRACT FROM AUTHOR]

The dissimilar butt joining of aluminum alloy and copper was successfully realized by cold metal transfer (CMT) welding–brazing with the help of preheating on copper. Preheating could balance the effect of the high thermal conductivity of copper on weld formation, and eliminate welding defects such as porosity, unfused zone, and cracks at the interface. Three layers of intermetallic compounds were observed at the brazing interface, namely, Al4Cu9, Al2Cu3, and Al2Cu. When the heat input was reduced to 648 J/mm, the total thickness of the interfacial IMC layers was suppressed to 4.83 μm, and the mechanical property of the joint was up to 91.35 MPa. The corrosion resistance of the Al/Cu welded joint was worse than that of the base metals, and corrosion occurred at the interfacial IMCs and the grain boundaries of the weld microstructure. [ABSTRACT FROM AUTHOR]

In this study, we examined how different stir casting stirring rates affected the mechanical properties of aluminum-copper (Al-Cu) alloys. Al-Cu alloys were cast and developed utilizing an electromechanical stir casting technique with stirring rates ranging from 0-90 revolutions per minute (rpm), and the alloys had Cu compositions of 0-15 wt. % (weight percent). The microstructural evolution was investigated using an advanced optical microscope. When the developed alloy materials were evaluated for microhardness and tensile strength, it was found that the raise in composition of copper and increase in stirring rate led to progressive improvements in microhardness while changes observed with the tensile strength were obviously indeterminate. The mechanisms responsible for the changes seen are also described. [ABSTRACT FROM AUTHOR]

Residual arsenic in copper matte is a source of arsenic contamination in subsequent processes in the smelting section of copper pyrometallurgy. In order to solve the impact of arsenic in copper matte on the subsequent process of smelting, this study removes arsenic from copper matte by adding an arsenic removal agent to the molten copper matte. The results show that the most difficult arsenic phase in copper matte is the residual arsenic in copper-arsenic alloys, based on which sodium carbonate was selected as the arsenic removal agent. The arsenic content in the copper matte was reduced by 98% under the optimal experimental conditions of a reaction temperature of 1250 °C, 4% sodium carbonate addition, and a reaction time of 60 min. The experimental results of the reaction mechanism show that sodium carbonate plays two main roles in the process of removing the intractable residual arsenic in copper matte. One is that sodium carbonate has a low melting point, which enhances the fluidity of the reactants. The other is that it can provide oxygen to the reaction system and convert arsenic in the copper-arsenic alloy into gaseous arsenic and arsenate. This study can provide new ideas for controlling arsenic pollution in copper pyrometallurgy. [ABSTRACT FROM AUTHOR]

Although there are studies devoted to lower Indium (In) addition, Sn-Bi alloys containing 10 wt.% In or more have been barely investigated so far. Higher In contents may offer the potential for improved joint production, better control over the growth of interfacial layers, and enhanced mechanical strength. The present article focuses on the solidification, wettability, adhesion strength, and interfacial intermetallic growth in the Sn-40%Bi-10%In alloy soldered on Cu and Ni pads. SEM-EDS, wettability tests, and tensile tests were performed. The contact angles were measured in Cu and Ni as 24° and 26°, respectively. Indium addition promoted coarsening of the as-solidified microstructure due to an increase in the alloy solidification range. The Bi spacing was increased at least three times, with a strong segregation of Bi towards the interface. The formation and growth of alloy/Cu reaction layers were also evaluated under the different aging conditions of the as-soldered joints, simulating real service. A growth kinetics model of the reaction layer showed that In increases the activation energy, thereby reducing the layer growth. The adhesions of the formed intermetallics films in Cu and Ni were analyzed using tensile tests. It was observed that the alloy/Ni couple exhibited better adhesion. Premature fracturing appears to happen in the alloy/Cu joint due to the higher intermetallic compound's (IMC) thickness, rough morphology, and coarser microstructure. Both ductile fracture features with dimples and cleavage zones associated with Bi, Cu6(Sn,In)5, and Ni3Sn4 intermetallics were observed. [ABSTRACT FROM AUTHOR]

Copyright of Rare Metals is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The production and characterization of UNS C65620 (CuZn3Fe2Si3) and UNS C87800 (CuZn15Si4) coded alloys were investigated. The alloys poured into the gravity die casting method were hot forged with a ram, followed by stress relief annealing heat treatment. While the formation of Cu4Si, Cu0.83Si0.17 and Cu5Zn8 phases were detected in the structure of the UNS C65620 coded alloy, Cu12.75SiZn2.92 and Cu3Zn intermetallics with the phases given above were observed in the structure of the alloy containing more Zn and Si. The formation of phases containing more Si and Zn resulted in an increase in both the hardness and strength of the UNS C87800 coded alloy, while the decrease in the % reduction of area and the observation of dynamic deformation aging caused the increase in both the wear rate and deformation hardening rate, which led to embrittlement of the alloy. The deterioration of the corrosion resistance of the UNS C87800 coded alloy can be attributed to the formation of Zn-rich corrosion products on the surface during corrosion.

Electrical contact materials are increasingly widely used, but the existing electric contact lubricants still have lots of room for improvement, such as anti-wear performance and lubrication life. Due to the excellent electrical and lubrication properties, graphene shows great potential in lubricating the sliding electrical contact interface, but there is a lack of relevant research. Some researchers have studied the lubrication performance of graphene between the gold-coated/TiN-coated friction pair at an ultra-low current. However, the lubrication performance of graphene on more widely used electrical contact materials such as copper and its alloys under larger and more commonly used current or voltage conditions has not been reported. In this paper, we study the lubrication performance of graphene in the copper and its alloys sliding electrical contact interface under usual parameters, which is explored through four aspects: different substrates—copper and brass, different test methods—constant voltage and constant current, different normal loads and durability test. The experiments demonstrate that graphene can significantly reduce the friction and wear on brass and copper under the above test methods and parameters, with low contact resistance at the same time. Our work is expected to provide a new lubricant for electrical contact materials and contribute to enriching the tribological theory of graphene. [ABSTRACT FROM AUTHOR]

The changes in the properties of copper and its alloys as a result of severe plastic deformation (SPD) are reviewed. The literature review shows that contemporary materials science is aimed at solving the problem of producing ultrafine-grained materials with high-angle grain boundaries. With using of the methods of severe plastic deformation, it is possible to obtain so-called bulk nanostructured materials with grain sizes of 0.1–0.2 microns and specific substructures containing the lattice and grain-boundary dislocations. Such structures are characterised by large elastic distortions of the crystal lattice. It is believed that such fine-grained structures should simultaneously provide a high level of plastic and strength characteristics due to special stressed high-angle grains. The article discusses SPD methods such as torsion with shear, equal-channel angular pressing, screw extrusion, all-round forging, rolling with shear, etc. Among the most significant results of SPD, it is worth highlighting the increase in strength, fatigue resistance and elastic properties of the material. These changes make copper and its alloys subjected to SPD very attractive for use in many industries, including electrical engineering, aviation, medicine, etc.

Although the origins of lost wax casting extend back into the 5th millennium BCE, it was not until the development of hollow core casting that life-sized metal sculptures could be produced. Based on existing evidence, the earliest adoption of this technique, which involves the inclusion of a clay core within a wax model, occurred in Iraq (Mesopotamia) during the Early Dynastic III period (ca. 2600–2350 BCE). To date, only one hollow core casting from the succeeding Akkadian period (ca. 2350–2150 BCE)—the Sargon Head in the collection of the Iraq Museum—has been studied from a technical point of view. The recent attribution of The Metropolitan Museum of Art's Head of a ruler to this formative period of hollow core lost wax casting provided the impetus for its examination by high-energy X-ray computed tomography—the most practical technique for an object that is continuously on display that could image in 3D the interior morphology of this sculpture given the considerable thickness of its metal walls. This scan revealed a markedly different style of production than the Sargon Head. Although further research on early castings is required to determine the chronological implications of the differences observed and to elucidate more generally the early development of hollow casting technology, the scan of the Head of a ruler provides evidence of some of the challenges encountered and problem-solving strategies used in the casting process. [ABSTRACT FROM AUTHOR]

This paper investigates the mechanical properties of AA2024 joints welded using the Friction Stir Welding (FSW) process, with a particular focus on comparing joints made with and without the inclusion of a commercially pure copper sheet between the edges being welded. The study aims to understand the influence of weld heterogeneity on the mechanical properties of FSW joints. Various joints were fabricated with a copper interlayer, and optimal process parameters—rotational speed, advancing feed, and tool geometry—were identified. Mechanical tests, including Rockwell B and Vickers hardness (HV) tests, as well as tensile tests, were conducted on both homogeneous and heterogeneous joints. The results showed that the presence of copper significantly affected the hardness distribution, particularly in the weld nugget. Heterogeneous joints demonstrated a notable increase in HV at the nugget and a reduced weld-affected area on both the advancing and retreating sides. The study found a strong correlation between process parameters, tool geometry, and the Ultimate Tensile Strength of the joints. Optimal mechanical properties were achieved in heterogeneous joints welded at 800 rpm and 40 mm/min with an 18 mm tool, resulting in a joint efficiency of 73%. These parameters differed significantly from those optimized for homogeneous joints, which were 1200 rpm and 100 mm/min with a 16 mm tool. It was also observed that exceeding 1000 rpm in rotational speed and 70 mm/min in feed speed is not advisable for heterogeneous welds. Future research should explore varying amount of copper and other materials, as well as different interposition methods, to further understand their effects on the mechanical properties of FSW joints. [ABSTRACT FROM AUTHOR]

A comprehensive study of structural-phase transformations and physical and mechanical properties of metastable Cu–39.5 wt % Zn α + β alloy with the shape memory effect subjected to thermomechanical treatments including cold rolling and annealing has been carried out. The features of the fine structure formed at the intermediate and bainitic phase transformations have been studied using optical and electron microscopy as well as X-ray phase analysis. The temperature intervals of bainitic 3R/9R and other phase transformations were established by differential scanning calorimetry upon heating up to 500°C. In the case of the hardened alloy, the temperature of the bainitic transformation was close to 170°C. In mechanical tests conducted using uniaxial tension, it has been demonstrated that cold deformation and post-deformation heat treatment under different modes can be employed to obtain the alloy in high-strength or ductile states. These states are characterized by an ultimate strength (σu) greater than 700 MPa and a relative elongation (δ) greater than 40%, respectively. [ABSTRACT FROM AUTHOR]

Balancing the hardness and electrical conductivity of copper alloys within complex compositions and processes poses a formidable challenge. This study proposes a strategy combining machine learning with the Pareto front techniques to identify optimal combinations of composition and processing for Cu-xTi (1.5 ≤ x ≤ 5.4, in wt.%) alloys. Through thermodynamic calculations, precipitation simulations, and experimental characterizations, the microstructural evolution of β'-Cu4Ti precipitates in the designed alloys was explored. The interpretability and predictability of the machine learning model played a crucial role in understanding impact of complex alloy compositions and processing on the evolution of properties, thereby guiding the design of Cu-Ti alloys towards improved attributes. A novel strategy integrating machine learning with Pareto front is proposed for alloy design, facilitating the rapid screening of Cu-Ti alloys that exhibit superior hardness and electrical conductivity simultaneously. [ABSTRACT FROM AUTHOR]

The development of silicon (Si) photoanodes for photoelectrochemical (PEC) oxidation is highly crucial for the progress of solar‐driven hydrogen production. Apart from the typical water oxidation reaction or oxygen evolution reaction (OER), the urea oxidation reaction (UOR) is gaining more attention due to favorable thermodynamics. In this work, we study Si photoanodes modified with electrodeposited copper‐nickel (CuNi) alloy for OER and UOR. The optimized photoanodes exhibit a low onset potential of 1.15 V vs reversible hydrogen electrode (RHE) and a current density of 6 mA cm−2 at 1.23 V vs RHE (the thermodynamic potential for water oxidation) for OER. Further, CuNi alloy‐modified photoanodes can drive the UOR at a lower onset potential (1.05 V vs RHE) and generate a higher current density of 31 mA cm−2 at 1.23 V vs RHE. Importantly, the CuNi alloy can extend the stability for UOR under PEC conditions when compared to a planar Ni film deposited by a vacuum‐based process. This work demonstrates that CuNi alloy can further improve the properties of inhomogeneous metal‐insulator‐semiconductor Si photoanodes which can be efficiently utilized for both OER and UOR. [ABSTRACT FROM AUTHOR]

To obtain a copper alloy with a higher softening temperature, a Cu-Ni-Ti alloy was obtained by the traditional smelting method. And, on this basis, we discuss the effects of atom percentages of different Ni-Ti alloys and the mass percent of Ni + Ti on the properties of single-stage aging of Cu-Ni-Ti alloys at 600°C. The results indicate that the alloy with a Ni/Ti atomic ratio of 2 and a total Ni + Ti content of 3 wt.% exhibits the best performance match. After aging at 600°C for 8 h, the Cu-Ni-Ti alloy's softening temperature exceeded 720°C. This property surpasses that of most age-hardened copper alloys. The corresponding hardness and conductivity were 171 HV and 58% IACS, respectively, which is slightly lower than the commonly used time-reinforced copper alloy. After calculation, the Cu-Ni-Ti alloy with a Ni:Ti atomic ratio of 2 and a total Ni + Ti content of 3 wt.% is referred to as the Cu-2.13Ni-0.87Ti alloy. Transmission electron microscopy observations indicated that the precipitated phase in the aged Cu-2.13Ni-0.87Ti alloy consists of dispersed nanoparticles of Ni3Ti, which have a semi-coherent interface relationship with the matrix. Upon holding the peak-aged Cu-2.13Ni-0.87Ti alloy at different temperatures for 1 h, it was noted that the precipitates exhibited significant coarsening. Furthermore, when the holding temperature surpassed 700°C, the rate of coarsening increased significantly, accompanied by a rapid decline in hardness. [ABSTRACT FROM AUTHOR]

By using the joined or welded materials of dissimilar metals, the characteristics and performance of products and parts can be improved. The combination of copper and aluminum is difficult to weld. In this study, the impact joining of copper C1100 and aluminum alloy A6061-T6 plates at the edges was investigated to explore the appropriate joining conditions. The plates are joined with newly created surfaces generated by the high-speed compressive deformation with sliding motion. The shape near the interface was a tapered trapezoid with a flat top. The joining length in the plate thickness direction was shorter than the plate thickness, and notches were observed near both plate surfaces. The length became slightly longer by setting a larger top width of the C1100 plate than that of A6061-T6. The joint efficiency increased by approximately 10%. Applying the emery paper finish to the surface of the plate eliminated the non-joining result in multiple experiments. The finishing direction is effective only in the longitudinal direction of the plate. In the tensile test on the dumbbell-type specimen with reduced thickness to eliminate notches, most results showed a fracture at the C1100 portion. The estimated temperature rise of the C1100 is more than about 250 K during the impact deformation. Hence, the strength of the A6061-T6 becomes lower than that of C1100 during the process, and the softened layer of aluminum comes out under pressure, resulting in good joining performance. [ABSTRACT FROM AUTHOR]

A custom tribometer was developed to measure friction coefficient and temperature in high-pressure, low-velocity conditions, specifically for studying copper alloys used in sliding bearings for heavy equipment. Using this equipment, two commercial alloys were tested to evaluate friction coefficient, specific wear rate, thermal behavior, and subsurface strain. The results, validated through comparison with reference commercial equipment and uncertainty estimates, met acceptable criteria for tribological tests, with an uncertainty estimate value for the friction coefficient of 0.4%. The tribological tests confirmed the importance of solid lubrication in high-lead bronzes and the high wear resistance of Cu-Al-Ni-Fe alloys, which directly influence temperature, subsurface strain, and respective wear mechanisms. [ABSTRACT FROM AUTHOR]

Unmanned Aerial Vehicles (UAV), due to the ability of carrying huge payload, have wide applications from military surveillance, medicinal supply to agricultural purposes. To fulfil these applications effectively, the body frame of quadcopter must be able to withstand the various loading conditions. The present study deals with the structural analysis of a quadcopter frame to study the effect of specified loading conditions on the body frame. Further modal analysis was done for material optimization. Four different materials were selected which includes Aluminium alloy, Copper alloy, Carbon fibre, E-glass fibre. From modal analysis six modes with respective frequencies for all four materials were obtained. Based on the results, suitable material was selected which will suit the specified loading conditions. [ABSTRACT FROM AUTHOR]

The production and characterization of UNS C65620 (CuZn3Fe2Si3) and UNS C87800 (CuZn15Si4) coded alloys were investigated. The alloys poured into the gravity die casting method were hot forged with a ram, followed by stress relief annealing heat treatment. While the formation of Cu4Si, Cu0.83Si0.17 and Cu5Zn8 phases were detected in the structure of the UNS C65620 coded alloy, Cu12.75SiZn2.92 and Cu3Zn intermetallics with the phases given above were observed in the structure of the alloy containing more Zn and Si. The formation of phases containing more Si and Zn resulted in an increase in both the hardness and strength of the UNS C87800 coded alloy, while the decrease in the % reduction of area and the observation of dynamic deformation aging caused the increase in both the wear rate and deformation hardening rate, which led to embrittlement of the alloy. The deterioration of the corrosion resistance of the UNS C87800 coded alloy can be attributed to the formation of Zn-rich corrosion products on the surface during corrosion. [ABSTRACT FROM AUTHOR]

Objective: Metallic copper alloys have gained attention recently as a cutting-edge antibacterial weapon for areas where surface hygiene is crucial. The present study aimed to assess copper coupons (99% Cu) for their potential to decrease the viability of various Enterobacteriaceae strains from inanimate hospital surfaces. Methods: This in vitro-experimental study was conducted at the Microbiology Laboratory, Faculty of Natural and Life Sciences and Earth and Universe Sciences, University of Guelma, and Khodja Ahmed Public Hospital Establishment, Algeria, for a period of six months from January to May 2022. A total of 85 samples were collected from patient room door handles and bed rails at the government hospital in Guelma State, from which 12 enterobacterial isolates were obtained. These isolates were evaluated for susceptibility to copper and polyvinyl chloride (PVC) coupons using plate counts to determine bacterial viability after 72 hours of incubation at 37°C or room temperature (25°C). Antibiotic sensitivity testing was then carried out using a modified Kirby-Bauer disc diffusion method. Copper coupons' ability to either select for or create antibiotic resistance is also determined. Results: Copper showed a bactericidal effect after three hours for Serratia odorifera and six hours for Escherichia coli. Whereas it was shown that within three days of selection, 83.33% of Enterobacteriaceae strains are capable of rapidly acquiring Cu resistance. Indeed, the increase in temperature reduced the effects of Cu (p<0.05; Student's t-test). Antimicrobial susceptibility testing revealed that the copper-resistant bacteria were less sensitive than their predecessors. Citrobacter freundii strains showed the highest incidence of multidrug resistance. The most significant findings included widespread resistance to beta-lactams (100%-75%) and chloramphenicol (66.67%). Conclusion: These results suggest that prolonged copper usage may contribute to the development of antibiotic resistance, which could have significant ramifications. [ABSTRACT FROM AUTHOR]

Parts with interior voids created by the LPBF process are known to have the potential to cause fracture when subjected to mechanical loading. In this research, the key process parameters such as laser thickness (LT), scanning speed (SS), and laser power (LP) were taken into consideration to avoid the void formations which was the major reason for affecting the structural integrity. So, void formations (V), ultimate tensile strength (UTS) and reduced modulus (RM) were considered as the response parameters in this study. The entropy-associated weighted aggregated sum product assessment (WASPAS) approach was implemented to examine the favorable conditions which substantiated that the LT is the most influential parameter in nucleation of voids. The verification experiments prove that the void formation was reduced by 98.6% and the UTS and RM were enhanced by 52.17 and 31.7%. [ABSTRACT FROM AUTHOR]

Al–Zn–Mg–Cu alloys have been prepared using the gravity die-casting process. The influence of copper addition on microstructure, mechanical and thermal properties are studied. The experimental alloys were prepared using 5754 alloys, Al–Cu alloys, and pure zinc (solid form). Alloys are mechanically stirred for uniform distributions of alloying elements and precipitate phases. Four alloys with different copper weight percentages (0.02 wt%, 0.89 wt%, 1.57 wt%, and 3.34 wt%) were prepared. The α-Al and η (MgZn2) phases are observed in as-cast Al–Zn–Mg alloy. The addition of copper in Al–Zn–Mg alloys formed a θ phase (Al2Cu). Micro-Vickers hardness of Al–Zn–Mg–Cu alloy increased (from 116 HV1 to 133 HV1) with copper addition (0.02–1.57 wt%) at firstly due to the formation of θ phase (Al2Cu). Then, micro-Vickers hardness decreases due to high amounts of precipitates. Copper addition reduces the melting point (623–612 °C) and precipitation temperature (472–466 °C) of aluminum alloy. Al–Zn–Mg alloys have tensile strength of 422 MPa due to precipitates phase formation of η and T phases, solid solution strengthening (zinc and magnesium). Copper addition increases tensile strength due to the formation of θ phases. After achieving a strength of 486 MPa at an elongation of 3.72% (1.57 wt% Cu), tensile strength reduces due to a higher amount of precipitates. [ABSTRACT FROM AUTHOR]

The basis for limiting the durability of the internal combustion engine is the wear of parts of the cylinder-piston group and the crankshaft, which are characterized by the presence of small gaps between the plunger and the sleeve. High pressure is provided by the presence of small gaps between the plunger and the sleeve (at the level of 1-3 microns). The recovery method proposed by us is based on electrochemical technologies in polyethylene glycol-400 (PEG-400) electrolyte, which dissolves in water, has lubricating properties and fire-fighting ability, belongs to nonionic surfactants. It is necessary to establish the conditions for the formation of protective films on the friction surface of steel 20 according to LS59-1 using the lubricating properties of polyethylene glycol oils in conditions of unidirectional sliding friction. The presented mechanism of electrolytic transfer of constituent elements of alloys allows indicating the surface saturation of the cathode with one of its alloying elements, in this case from a copper alloy, without taking into account the limited difference in the electrode potential between the friction surfaces, taking into account the deformation component. The main advantage of PEG-400 is its environmental friendliness, which is guaranteed by its chemical composition and solvent - water. [ABSTRACT FROM AUTHOR]

Methods of transmission and scanning electron microscopy are used to study premartenstic states and their relation to martensitic transformations in the alloys Cu–38 wt % Zn and Cu–39.5 wt % Zn with shape memory effect. Analysis of the observed diffusion scattering of electrons is carried out, including in situ experiments at heating and cooling and the defect condition of the internal substructure of austenite and martensite. The crystallographic models of martensitic transitions β2 → , β2 → , and β2 → are proposed based on the crystallographic data obtained in the premartensitic state. [ABSTRACT FROM AUTHOR]