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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., Competing Interests: Declaration of conflicting interestsThe authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Nantokite (CuCl) locked inside subsurface micro-pits has been recognised as the driving force to the form of corrosion called bronze disease. The use of the traditional corrosion inhibitor benzotriazole is questioned because of toxicity. So there is a need for alternative conservation treatments. This work is focused on the experimental design to test the effectiveness of sodium oxalate followed by treatment with limewater to face bronze disease on outdoor bronzes. A number of foundry bronze coupons were exposed to weathering at Genoa Experimental Marine Station (GEMS) exposure site and sprayed twice a week with a 5% NaCl solution for the first 124 days. After 562 days of natural weathering, the patinas on coupons were characterised with non-destructive techniques (NDT) and the presence of nantokite was verified. We designed a workflow, as similar as possible to conservation treatments on real artworks, to test a 3% w/v sodium oxalate treatment with two different application times, with or without limewater, on the coupons. The effectiveness of the treatments was analysed by comparison of surface properties by several NDT measurements. A statistical approach and XRD measurements directly on the corroded bronze surfaces are suggested as an effective way to characterise and compare the overall behaviour of bronze disease treatments for conservation., (© 2022. The Author(s).)

The oral bioaccessibility of copper alloys and pure metals was assessed using in vitro methods with synthetic saliva and gastric fluid. The metal-specific migration rates from polished alloy surfaces are higher in gastric (pH 1.5) than in saliva fluid (pH 7.2). In both media, migrations are higher for lead than for other metals. The bioaccessible metal concentrations in massive copper alloys, after 2 h in gastric fluid, was only <0.01%-0.18%, consistent with the low surface reactivity of copper alloys (defined as 1 mm spheres). The average metal-specific migrations of cobalt, copper, nickel and lead from most of the tested copper alloys in gastric media are comparable to the ones from their pure metals. The data further show that the bioaccessibility of metals in massive copper alloys primarily depends on the bioelution medium, the exposed surface area and the composition of the alloy. The tested copper alloys show only limited evidence for influence of alloy surface microstructure. This is contrary to findings for other alloys such as stainless steel. Additional investigations on other copper alloys could allow to further refine these conclusions. These findings are useful for establishing the hazard and risk profile of copper alloys following oral exposure., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Biofouling and corrosion phenomena dramatically reduce the functionality of industrial cooling circuits, especially in marine environments. This study underlines the effectiveness of a low level chlorination treatment of seawater to prevent biological fouling and biocorrosion. Reported examples emphasize the reaction of chlorine with bromide, ammonia and organic compounds in seawater and the effectiveness of a treatment performed in such a way to guarantee a residual concentration lower than 3μM at the outlet of the condensers. In a brief review of antifouling strategies, alternatives to chlorination and the monitoring approach able to optimize the treatments are also reported. An integrated, on-line system based on electrochemical probes (Biox system and a linear polarization resistance probe) demonstrated to be sufficient to monitor in real time: corrosion, biofilm growth and chemical treatments based on chlorine or alternative oxidant products (chlorine dioxide, etc.). A careful electrochemical monitoring and the optimized treatments help the plant operators of industrial cooling circuits prevent the decay of the equipment performance, allowing at the same time the control of the halogenated by-products formation., (Copyright © 2014 Elsevier B.V. All rights reserved.)

The present paper reports the on-line monitoring of corrosion behavior of the CuNi 70:30 and Al brass alloys exposed to seawater and complementary offline microbiological analyses. An electrochemical equipment with sensors specifically set for industrial application and suitable to estimate the corrosion (by linear polarization resistance technique), the biofilm growth (by the BIOX electrochemical probe), the chlorination treatment and other physical-chemical parameters of the water has been used for the on-line monitoring. In order to identify and better characterize the bacteria community present on copper alloys, tube samples were collected after a long period (1year) and short period (2days) of exposition to treated natural seawater (TNSW) and natural seawater (NSW). From the collected samples, molecular techniques such as DNA extraction, polymerase chain reaction (PCR), denaturing gradient gel electrophoresis (DGGE) and identification by sequencing were performed to better characterize and identify the microbial biodiversity present in the samples. The monitoring data confirmed the significant role played by biofouling deposition against the passivity of these Cu alloys in seawater and the positive influence of antifouling treatments based on low level dosages. Molecular analysis indicated biodiversity with the presence of Marinobacter, Alteromonas and Pseudomonas species., (Copyright © 2013 Elsevier B.V. All rights reserved.)

Efficient and sustainable electrocatalysts for the hydrogen evolution reaction (HER) using earth-abundant elements are crucial for eco-friendly hydrogen production, particularly under neutral and acidic conditions. In metallic alloys, careful selection of alloying elements and control over the composition, morphology, electronic structure, and structural defects are expected to tune electrocatalytic activities. In this work, we introduce a two-step electrodeposition approach to create a 3D porous trimetallic alloy, Cu@Cu–Ni–Co, exhibiting excellent catalytic activity and stability for HER in neutral and acidic environments. The process begins with the electrodeposition of 3D copper dendrites, which was found to be crucial for the catalyst's mechanical stability, followed by the deposition of the trimetallic alloy, where copper's inclusion promotes the controlled growth of the alloy's 3D structure. The Cu@Cu–Ni–Co catalyst outperforms Cu@Ni, Cu@Co, Cu@Ni–Co, and GC@Cu–Ni–Co electrocatalysts in neutral and acidic conditions, highlighting the importance of the developed electrodeposition approach. In 1.0 M phosphate-buffer solution (PBS), Cu@Cu–Ni–Co achieves a current density of 10 mA cm−2 at an overpotential of 275 mV with a Tafel slope of 134 mV dec−1, maintaining remarkable stability in both acidic and neutral conditions at high current densities (48–165 mA cm−2) for up to 50 h without any decline in activity. [Display omitted] • Developed a two-step electrodeposition method to create a 3D porous Cu@Cu–Ni–Co alloy, optimizing HER performance in neutral and acidic conditions. • Used initial copper dendrite deposition for enhanced mechanical stability and precise microstructural control of the trimetallic alloy. • Achieved an overpotential of 275 mV with the Cu@Cu–Ni–Co catalyst, surpassing Cu@Ni, Cu@Co, Cu@Ni–Co, and GC@Cu–Ni–Co. • Maintained high stability at current densities of 48–165 mA cm−2 for 50 h without degradation, under both acidic and neutral conditions. • Demonstrated excellent compatibility and effectiveness on various substrates including glassy carbon, nickel foam, and ITO. [ABSTRACT FROM AUTHOR]

This study investigated the dependence of irradiation fluence and pulse duration on the non–thermal alloying of Cu and Sn through laser irradiation. Femtosecond and picosecond laser irradiation were applied to the GaN part of a bilayer of Cu and Sn deposited on GaN. The laser beam operated at a wavelength and repetition rate of 1030 nm and 1 MHz, respectively, with pulse durations of 0.65 and 38 ps. Subsequently, the irradiated samples were thinned using a focused ion beam, and the cross-sections were examined with transmission electron microscopy. The lattice constants of the resultant phases were identified from selected area diffraction patterns. In data analysis, we identified the phases as β-Sn and ε-phases first, if discernible within a 5% error margin, employing high-temperature phases when identification was not possible. In the irradiated area, only Cu and Sn were detected under a lower fluence and shorter pulse duration. However, δ-phases, which are alloys of Cu and Sn, formed at relatively higher fluences and longer pulse durations. This high-temperature phase, unique to picosecond laser irradiation, cannot be obtained through conventional thermodynamic processes, highlighting the unique capabilities of laser-induced processing in creating novel alloy phases. These findings advance our understanding of laser-material interactions and provides a foundation for developing advanced materials with tailored properties for various applications. [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 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]

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]

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 continuous industrial development that occurs worldwide generates the need to develop new materials with increasingly higher functional properties. This need also applies to the basic material for electricity purposes, which is copper. In this article, we carry out studies on the influence of various alloying elements such as Mg, In, Si, Nb, Hf, Sb, Ni, Al, Fe, Zr, Cr, Zn, P, Ag, Sc, Pb, Sn, Co, Ti, Mn, Te and Bi on the electrical and mechanical properties of ETP-grade copper. The research involves producing copper alloys using the gravity die casting method with alloy additions of 0.1 wt.%, 0.3 wt.% and 0.5 wt.%. All resulting materials are cold-worked to produce wires, which are subsequently homogenized and annealed. The materials produced in this manner undergo testing to determine their specific electrical conductivity, tensile strength, yield strength, elongation and Vickers hardness (HV10 scale). [ABSTRACT FROM AUTHOR]

Zinc-copper alloy ash contains Cu, Zn, Al, Ni, Sn, Pb and other non-ferrous metals. In this paper, t he effective treatment of zmccopper ash in different particle size ranges ss realized by screening. The effects of sulfuric acid content, temperature, time, i iquid-soiid ratio, rotation speed, oxidant and roasting conditions on the selective eaching of different meta! were investigated. The resutts show that the zinccopper ash with partid size kss than 0. 15 mm ss caHned at 750 °C for 3 hours, and then leached at 85 °C, s uHunc acid content of 1. 2 g/g ash, iiquid-to-solid ratio of 5/1, sirring speed of 400 r/min, H202 0. 075 mL/g ash for 5 h. The removal rate of zinc ss 93. 40%, and the removal rate of copper ss 0. 23%. Compared with the initia1 copper ash, the ZnO n the copper ash after roasting and leaching ss greatly reduced. The leaching residue was mixed with copper slag with a particle size of 0. 15-0. 25 mm, roasted at 750 C for 4 hours, and then washed wI 2 mol/L suHurtc acid solution for 5 hours and washed wI water under the same condiions. The steps can remove a !arge number of impurtty metal e!ements inthe copper slag. The phase composition of the copper slag after pickling is mainly Cu, and the proportion of Cu elements reach 92. 52%. [ABSTRACT FROM AUTHOR]

The study evaluates and interprets a new discovery of fragments of a triangular votive tablet for Jupiter Dolichenus from Újezd u Rosic, District of Brno-Land (Moravia, Czech Republic) and places it in the context of Central European barbaricum and the Roman Middle Danube region. The fragments of the votive tablet from Újezd u Rosic testify, due to their individual appearance in the landscape, more to the ritual behavior of the local barbarian population than to the loss of an object. The presence of the votive tablet outside the Roman border can hypothetically be associated with the events of the Marcomannic Wars or with the period of unrest between the Germanic tribes and Roman power under the late Severans. The present study examines the relationship of the barbarians to the cult of Jupiter Dolichenus based on the discovery of fragments of a triangular dedicatory plaque in Újezd u Rosic, Czech Republic. The fragments show relief decoration with vegetative and zoomorphic motifs as well as a coating with white metal. The finds are the first of their kind in the Czech Republic and differ from finds in Slovakia for which no origin data is available. The elemental composition of the copper alloy of the plaque as well as the characteristics of its decoration and coating are analyzed. The fragments are kept in the South Moravian Museum in Znojmo. The article describes the decorative fields of triangular plaques, which were probably used as military standards. The plaques were likely carried in processions to worship a deity and could have been valuable dedicatory gifts. They are divided into three main fields: atmospheric part (sun and moon), deities, and terrestrial part (Castores). The plaques also contain representations of male figures in military attire, likely representing the Dolichenian canon. The plaques were decorated using a special technique typical of the Göldenitz group and dated to the late 2nd to early 3rd century. The exact dating of the finds from Újezd u Rosic is difficult, but they could date from the 2nd or 3rd century. The Burg-Kumpfmühl treasure (Fig. 7,2-4) dates from the 3rd century and was discovered during the Marcomannic Wars in 170/172 AD. The treasure trove contains a bowl from the Weissenburg treasure, which is dated to the 230s or the mid-3rd century. The popular decorative motifs are also found on other parts of Roman armor dating to the end of the 2nd century and the 3rd century. The treasure trove could date from the second half of the 2nd century to the beginning of the 3rd century. The chemical analysis of the treasure trove shows that it consists of a thin sheet of metal coated with an alloy of copper, zinc, and tin. The treasure trove was likely made through hammering and chasing. The cult of Jupiter Dolichenus spread mainly through soldiers, traders, and officials connected to the military and provincial administration. The article deals with the cult of Jupiter Dolichenus in the Middle Danube region and in Central European barbaricum. It is noted that the cult already existed under Hadrian and spread further during the Severan dynasty. [Extracted from the article]

Aluminium-Silicon (Al-Si) based alloys are gaining more prominence among researchers for automotive applications. In this paper, the impact of copper alloying element and artificial ageing treatment on the mechanical response and microstructural evolution of Al-Si based alloys synthesised from aluminium scrap are examined, as there is need to gear up the urge for the usage of metallic scraps for production of alloys for automotive applications. The as-cast Al-Si alloy and its form with copper as alloying element (1.5% and 3% Cu) were produced using liquid metallurgy route. Solution heat treatment was carried out at 500℃ and artificial ageing was carried out at 190℃ for 0.5, 1, 1.5, 2 and 2.5 h. Mechanical properties and microstructural characterisations of the as-cast and artificially aged forms of Al-Si based alloys were performed. The hardness tests were performed according to ASTM A29/A29M–15. Impact strength was determined according to ASTM D256. Tensile tests were performed based on ASTM E8. Microstructures of the synthesised Al-Si alloys were examined using optical microscopy and scanning electron microscopy techniques. In as-cast condition of the Al-5Si-Cu alloy, impact strength increases with increase in copper content. Al5Si-Cu alloy with 3% copper content and artificially aged at 190°C for 2.5 h exhibited the highest impact strength. Hardness number increases with the increase in copper content up to 1.5% and the ageing time. Additional increase in the ageing time yielded decrease in the hardness number. Results revealed that artificial ageing enhances mechanical and microstructural characteristics of the Al-Si alloys. Ageing treated Al-Si alloys exhibited peak hardness, impact strength and ultimate tensile strength (UTS) values of 77.47 kgf/mm2, 17 J/mm2 and 137.80 MPa, respectively. The obtained results are indicative of mechanical properties enhancement when compared with as-cast Al-Si alloys with maximum hardness, impact strength and UTS of 43.71 kgf/mm2, 12.92 J/mm2 and 123.18 MPa, respectively. Significant improvement in mechanical properties was achieved in Al-Si-Cu alloy with copper content and artificial ageing when compared to that without copper inclusion. This may be attributed to the evolution of equiaxed precipitates and the fact that copper-rich Al-Si-Cu alloys promotes formation of precipitation strengthening phases of α-AlFeMnSi. This study shows that the mechanical properties of Al-5Si-Cu alloys produced using aluminium scrap-based materials were enhanced using artificial ageing treatment and the benefit can be utilised for automotive applications. [ABSTRACT FROM AUTHOR]

In the current work, a novel medium entropy copper alloy was designed with the aim of avoiding the use of expensive, hazardous or scarce alloying elements and instead employing widely available and cost-effective alternatives. In order to investigate this unknown region of multicomponent alloy compositions, the thermo-physical parameters were calculated and the CALPHAD method was utilized. This led to the design of the Cu50Zn25Al20Sn5 at. % (Cu53.45Zn27.49Al9.08Sn9.98 wt. %) alloy with a relatively low density of 6.86 g/cm3 compared with conventional brasses. The designed alloy was manufactured through vacuum induction melting, producing two ingots weighing 1.2 kg each, which were subjected to a series of heat treatments. The microstructural evolution of the alloy in the as-cast and heat-treated conditions was assessed through optical and scanning electron microscopy. The hardness of the as-cast and heat-treated alloy at room temperature was also studied. The alloy was characterized by a multiphase microstructure containing a major Cu-rich (Cu–Zn–Al) matrix reinforced with a secondary Zn-rich (Zn–Cu) phase and pure Sn. In terms of mechanical properties, the developed alloy exhibited high hardness values of roughly 378 HV0.2 and 499 HV0.2 in the as-cast and heat-treated conditions, respectively. [ABSTRACT FROM AUTHOR]

Alloying nanoclusters (NCs) has emerged as a widely explored and versatile strategy for tailoring tunable properties, facilitating in‐depth atomic‐level investigations of structure‐property correlations. In this study, we have successfully synthesized six atomically precise copper NCs alloyed with Group 10 metals (Pd or Pt). Notably, the Pd0 or Pt0 atom situated at the center of the distorted hexagonal antiprism Pd0/Pt0@Cu12 cage, coordinated with twelve Cu+ and two tBuC≡C− ligands. Moreover, ligand exchange strategies demonstrated the potential for Cl− and Br− to replace one or two alkynyl ligands positioned at the top or side of the NCs. The chirality exhibited by these racemic NCs is primarily attributed to the involvement of halogens and a chiral (Pd/Pt)@Cu18 skeleton. Furthermore, all the NCs exhibit near‐infrared (NIR) luminescence, characterized by emission peaks at 705–755 nm, lifetimes ranging from 6.630 to 9.662 μs, and absolute photoluminescence quantum yields (PLQYs) of 1.75 %–2.52 % in their crystalline state. The experimental optical properties of these NCs are found to be in excellent agreement with the results of theoretical calculations. These alloy NCs not only offer valuable insights into the synthesis of Pd0/Pt0‐Cu alloy NCs, but also bridge the gap in understanding the structure‐luminescence relationships of Pd0/Pt0‐Cu molecules. [ABSTRACT FROM AUTHOR]

With the continuous integration of semiconductor devices, the requirements of the size accuracy and surface quality of etched lead frames are stricter. The etchant is a key factor in the etching process and etched surface quality, while the effects of the difference in etchants on the etched surface morphology of Cu alloy have not been directly studied. In this study, aqua regia, acidic FeCl3 and two CuCl2 solutions were used as etchants, and different CuCrSn specimens were etched and characterized. The results show that the etching rate in aqua regia is high, and the grain orientation, grain boundary (GB) and dislocations have significant influences on the local etching rate. The preferential etching of some atomic planes forms steps between the grains with different orientations, and preferential etching around the GB and dislocation group forms grooves, resulting in high surface roughness. For the surfaces etched by the FeCl3 and CuCl2 etchants, the steps and grooves are blurred; thus, they are less rough. The CuCrSn alloy surface etched by the aqua regia is clean, with little Cr-rich particles, while high-density Cr-rich particles remain on the surfaces etched by the FeCl3 and CuCl2 etchants. For the same kind of etchant, the ion concentration can affect the etching mechanism, rate and the etched surface morphology. [ABSTRACT FROM AUTHOR]

Key Takeaways: It's important for the water industry to determine which corrosion tests are suitable to evaluate potential alloys for service line components buried underground. Two dezincification tests were effective at correlating to field experience. Electrochemical corrosion tests using "low‐ and high‐corrosive" synthetic soil with neutral pH were not generally effective in predicting field experience. [ABSTRACT FROM AUTHOR]

Copper-based alloys designed to combine high electronic and thermal conductivities with high mechanical strength find a wide range of applications in different fields. Among the principal representatives, strongly diluted CuAg alloys are of particular interest as innovative materials for the realization of accelerating structures when the use of high-gradient fields requires increasingly high mechanical and thermal performances to overcome the limitations induced by breakdown phenomena. This work reports the production and optical characterization of CuAg crystals at low Ag concentrations, from 0.028% wt to 0.1% wt, which guarantee solid solution hardening while preserving the exceptional conductivity of Cu. By means of Fourier Transform Infrared (FTIR) micro-spectroscopy experiments, the low-energy electrodynamics of the alloys are compared with that of pure Cu, highlighting the complete indistinguishability in terms of electronic transport for such low concentrations. The optical data are further supported by Raman micro-spectroscopy and SEM microscopy analyses, allowing the demonstration of the full homogeneity and complete solubility of solid Ag in copper at those concentrations. Together with the solid solution hardening deriving from the alloying process, these results support the advantage of strongly diluted CuAg alloys over conventional materials for their application in particle accelerators. [ABSTRACT FROM AUTHOR]

Copper and its alloys with steel, including stainless steel, are soldered using brazing materials CuAgZn and CuAg- ZnSn. They are used for making connections in heating, cooling and renewable energy sources (RES) devices. The elements used in the above-mentioned alloys affect wettability, castability, corrosion resistance, impact resistance, plasticity, stress resistance and also increase the melting point of the solder. The article presents the impact of the percentage of alloying additives covered by the EN ISO 17672 standard on performance and susceptibility to soldering brazing materials Ag44 and Ag40Sn. [ABSTRACT FROM AUTHOR]

The effects of 0.1 wt.% Ca addition, heat treatment, and SPD processing using the MaxStrain module of the Gleeble thermomechanical simulator on the microstructure, mechanical properties, and electrical conductivity of Cu–0.7Mg (wt.%) alloy were investigated in this work. The binary alloy exhibited a single-phase microstructure, whereas the ternary alloy featured uniform dispersion of Cu5Ca intermetallic particles inside the grains as well as on grain boundaries. These particles resulted in an average hardness that was 33% higher than that of the binary alloy, as well as 13% higher yield strength and 13% higher ultimate tensile strength. The heat treatment process not only enhanced the yield strength and ultimate tensile strength of the samples, but also resulted in the partial spheroidization of Cu5Ca particles within the microstructure of the ternary alloy, resulting in its improved ductility. Following MaxStrain processing, ternary samples exhibited a smaller grain size and a higher fraction of high-angle grain boundaries than binary samples, which was attributed to the vital role of Cu5Ca intermetallic particles in hindering the dislocation motion during deformation. MaxStrain-processed samples exhibited marginally lower electrical conductivities than their initial counterparts; yet, all MaxStrain-processed samples satisfied the electrical conductivity threshold for classification as HSHC Cu alloys. [ABSTRACT FROM AUTHOR]

The tungsten-copper alloy is commonly used for the electrical contact in high current vacuum switch, where precise temperature monitoring of the contact is crucial for ensuring stable operation of the switch by radiation thermometry. However, accurate emissivity data of this alloy is necessary when using radiation thermometry for temperature measurement. Thus, the directional spectral emissivity of tungsten-copper alloy is investigated within the temperature range of 400–700 ℃ under vacuum in this work. The hemispherical total emissivity is calculated by numerically integrating the directional spectral emissivity. Experimental results found this tungsten-copper alloy agrees with the theoretical prediction of the electromagnetic theory, that is, the emissivity increases with increasing temperature, and decreases with increasing wavelength. A convergence phenomenon of spectral emissivity occurs when the polar angle exceeds approximately 50°. This means that the normal wavelength dependence undergoes a shift at high polar angles, which is typical behavior of metallic emissivity. Additionally, the effects of thermal cycle, surface roughness, and chemical composition on emissivity are analyzed in detail. Surface stress relaxation process results in a significant decrease in emissivity. Emissivity increases as the surface roughness and tungsten composition of alloy increases. However, the effects of surface roughness and chemical composition on emissivity gradually disappear at long wavelengths and high polar angles. [ABSTRACT FROM AUTHOR]

Copper-based materials have long been used for their outstanding thermal and electrical conductivities in various applications, such as heat exchangers, induction heat coils, cooling channels, radiators, and electronic connectors. The development of advanced copper alloys has broadened their utilization to include structural applications in harsh service conditions found in industries like oil and gas, marine, power plants, and water treatment, where good corrosion resistance and a combination of high strength, wear, and fatigue tolerance are critical. These advanced multi-component structures often have complex designs and intricate geometries, requiring extensive metallurgical processing routes and the joining of the individual components into a final structure. Additive manufacturing (AM) has revolutionized the way complex structures are designed and manufactured. It has reduced the processing steps, assemblies, and tooling while also eliminating the need for joining processes. However, the high thermal conductivity of copper and its high reflectivity to near-infrared radiation present challenges in the production of copper alloys using fusion-based AM processes, especially with Yb-fiber laser-based techniques. To overcome these difficulties, various solutions have been proposed, such as the use of high-power, low-wavelength laser sources, preheating the build chamber, employing low thermal conductivity building platforms, and adding alloying elements or composite particles to the feedstock material. This article systematically reviews different aspects of AM processing of common industrial copper alloys and composites, including copper-chrome, copper-nickel, tin-bronze, nickel-aluminum bronze, copper-carbon composites, copper-ceramic composites, and copper-metal composites. It focuses on the state-of-the-art AM techniques employed for processing different copper-based materials and the associated technological and metallurgical challenges, optimized processing variables, the impact of post-printing heat treatments, the resulting microstructural features, physical properties, mechanical performance, and corrosion response of the AM-fabricated parts. Where applicable, a comprehensive comparison of the results with those of their conventionally fabricated counterparts is provided. [ABSTRACT FROM AUTHOR]

Metallic alloys for a given application are usually designed to achieve the desired properties by devising experiments based on experience, thermodynamic and kinetic principles, and various modeling and simulation exercises. However, the influence of process parameters and material properties is often non-linear and non-colligative. In recent years, machine learning (ML) has emerged as a promising tool to deal with the complex interrelation between composition, properties, and process parameters to facilitate accelerated discovery and development of new alloys and functionalities. In this study, we adopt an ML-based approach, coupled with genetic algorithm (GA) principles, to design novel copper alloys for achieving seemingly contradictory targets of high strength and high electrical conductivity. Initially, we establish a correlation between the alloy composition (binary to multi-component) and the target properties, namely, electrical conductivity and mechanical strength. Catboost, an ML model coupled with GA, was used for this task. The accuracy of the model was above 93.5%. Next, for obtaining the optimized compositions the outputs fromthe initial model were refined by combining the concepts of data augmentation and Pareto front. Finally, the ultimate objective of predicting the target composition that would deliver the desired range of properties was achieved by developing an advancedMLmodel through data segregation and data augmentation. To examine the reliability of this model, results were rigorously compared and verified using several independent data reported in the literature. This comparison substantiates that the results predicted by ourmodel regarding the variation of conductivity and evolution of microstructure and mechanical properties with composition are in good agreement with the reports published in the literature. [ABSTRACT FROM AUTHOR]

Aftermarket additives are used to enhance the performance of internal combustion engines in specific aspects such as reducing wear, increasing power, and improving fuel economy. Despite their advantages, they can sometimes cause corrosion-related problems. This research evaluated the corrosiveness of four aftermarket additives on the corrosion of a high-leaded tin bronze alloy over 28 days at 80 °C in immersion tests. Among the evaluated products, three showed corrosive effects ranging from intermediate to severe. Notably, the visual appearance of the surfaces often did not indicate the underlying corrosive damage. Therefore, the assessment of corrosiveness was based on chemical characterizations conducted on both the drained oils and the bronze surfaces. The study found minimal oil degradation under the testing conditions, indicating that the primary cause of corrosion was the interaction between the specific additives and the metal elements of the alloy, rather than oil degradation itself. A direct correlation was observed between the dissolution of lead and copper and the adsorption of S and Cl-containing additives on the surfaces, respectively. The corrosive impact of Cl-containing additives in aftermarket formulations was significantly reduced when mixed with engine oil SAE 10W-30 (at a 25:1 ratio), suggesting a mitigated effect in combined formulations, which is the recommended usage for engines. [ABSTRACT FROM AUTHOR]

The need for innovative materials has increased in the current era of research and technology. Advanced materials such as shape memory alloys are in great supply in the industrial and commercial sectors. It is a unique and very uncommon metal alloy that can regain its original shape after being subjected to extremely low temperatures. SMAs may be classified as NiTi-based, Cu-based, or Fe-based depending on the metal-combination. Alloys based on copper have excellent elasticity and damping properties that allow them to withstand a broad variety of temperatures. Using the EDM method, this research investigates the effects of Ton, Toff, Ip, and GV on SR and dimensional deviation. 8.87 mm and 4.79 mm are the greatest and lowest values of SR that can be found, respectively. The dimensional deviation ranges from 0.03 mm to 0.28 mm, with a minimum value of 0.03 mm. Ton and Ip have a greater influence on surface roughness than Toff and GV. Images from SEM of workpiece samples show the production of micro-cracks as-well-as macro-ridges on the surface of the sample during EDM operations. SEM micrographs depicted the deviation in the dimensions of the workpiece samples after EDM operations on Cu-based SMA samples. [ABSTRACT FROM AUTHOR]

The use of copper as an antimicrobial agent has a long history and has gained renewed interest in the context of the COVID-19 pandemic. In this study, the authors investigated the antimicrobial properties of an alloy composed of copper with a small percentage of silver (Cu-0.03% wt.Ag). The alloy was tested against various pathogens, including Escherichia coli, Staphylococcus aureus, Candida albicans, Pseudomonas aeruginosa, and the H1N1 virus, using contact exposure tests. Results showed that the alloy was capable of inactivating these pathogens in two hours or less, indicating its strong antimicrobial activity. Electrochemical measurements were also performed, revealing that the small addition of silver to copper promoted a higher resistance to corrosion and shifted the formation of copper ions to higher potentials. This shift led to a slow but continuous release of Cu2+ ions, which have high biocidal activity. These findings show that the addition of small amounts of silver to copper can enhance its biocidal properties and improve its effectiveness as an antimicrobial material. [ABSTRACT FROM AUTHOR]

Cu-Be alloys exhibit excellent comprehensive performance in electrics, thermotics, and mechanics, and hence, they attract much attention. Among them, low-Be copper alloys are more environmentally friendly and promising. This study explores the effects of different Ni contents and heat treatment parameters on the properties, microstructures, and precipitates of Cu-0.2 wt% Be-x wt% Ni (0 < x < 2.0) alloys. The experimental results demonstrate that the fast cooling rate of cast alloys during solidification contributes to retention of the solute atoms in the copper matrix, which is beneficial for subsequent solid solution treatment. Furthermore, solid solution treatment slightly reduces the electrical conductivities, microhardness values, and compressive yield strengths of Cu-0.2 wt% Be-1.0/1.6 wt% Ni alloys. The optimal solution temperature and time are about 925 ℃ and 60 min, respectively. Aging treatment significantly increases the electrical conductivities, microhardness values, and compressive yield strengths of Cu-0.2 wt% Be-1.0/1.6 wt% Ni alloys. The best aging temperature is around 450 ℃. However, the properties of Cu-0.2 wt%Be-0.4 wt%Ni alloys remain unaffected by solution and aging treatments. Around x = 1.0, Cu-0.2 wt% Be-x wt% Ni alloys possess the best comprehensive properties, which are about 72%IACS of electrical conductivity, 241 HV of microhardness, and 281MPa of compressive yield strength, respectively. TEM and EDS analyses reveal that the precipitate evolution of Cu-0.2 wt% Be-1.0 wt% Ni alloys with aging time is GP zones → γ″ → γ′. Notably, a distinct double-peak age strengthening phenomenon emerges with Cu-0.2 wt% Be-1.0/1.6 wt% Ni alloys. The precipitation of plenty of GP zones at the early stage of aging should account for the first strengthening peak, and the strengthening mechanism transformation of the γ″ or γ′ phase from shear to Orowan should induce the second strengthening peak. This work may help to design new low-Be copper alloys and their preparation processes. [ABSTRACT FROM AUTHOR]

Owing to the high optical reflectivity of copper powder, the high-performance fabrication of copper alloys in the laser additive manufacturing (AM) field is problematic. To tackle this issue, this study employs the remelting process during laser powder bed fusion AM to fabricate defect-free and high-performance CuCrZr alloy. Compared to the non-remelting process, the remelting process yields finer grains, smaller precipitates, denser dislocations, and smaller dislocation cells. It realizes not only the dense molding of high laser reflectivity powders but also excellent mechanical properties and electrical conductivity (with an ultimate tensile strength of 329 MPa and conductivity of 96% IACS) without post-heat treatment. Furthermore, this study elucidates the influence of complex thermal gradients and multiple thermal cycles on the manufacturing process under the remelting process, as well as the internal mechanisms of microstructure evolution and performance improvement. [ABSTRACT FROM AUTHOR]

In this work, a numerical approach is applied to study the impact of local cooling conditions on the hot tearing in an aluminium‐copper alloy with iron, magnesium and silicon as impurities. At first, CALPHAD‐coupled multicomponent and multiphase‐field simulations were performed to elucidate the effect of cooling conditions on solidification morphology in the final, critical stage of solidification. Then, the evolution of the melt flow permeability is derived from the simulated three‐dimensional microstructures and discussed in the context of the Rappaz‐Drezet‐Gremaud criterion for hot tearing susceptibility. With increasing cooling rates, the microstructure becomes finer and the resulting permeability first increases and then saturates within the investigated range. It is shown that the Rappaz‐Drezet‐Gremaud hot‐tearing criterion in combination with microstructure simulations responds to different cooling conditions in contrast to a Scheil‐Gulliver based model or an evaluation of the average Kou‐index. [ABSTRACT FROM AUTHOR]

[Display omitted] Bioinspired hierarchical design demonstrates a promising microstructural solution to circumvent multiple intricate property trade-offs in artificial materials. However, it remains extremely challenging to tailor structural hierarchies feasibly and synthetically, particularly for bulk materials. Here, a counterintuitive strategy is reported–exploring multiscale microstructural heredities for highly-developed dendritic hierarchies in as-cast bulk alloys. During optimized thermomechanical processing, we carefully control these dendrites to be progressively deformed, elongated, aligned and refined, rather than completely destroying them as in conventional alloy processing paradigms. As such, a hierarchical fibrous lamellar (HFL) structure–resembling those of shell and bamboo–is controllably designed in a technologically-important CuCrZr alloy. This innovative HFL design promotes multiple synergetic micro-mechanisms with sequential multiscale interactions and salient biomimetic attributes, thereby affording exceptional multifunctionality, especially record-high strength–ductility–conductivity combination. At more fundamental levels, multiple previously inaccessible deformation and reinforcement mechanisms are activated by exploiting the HFL structure-enabled complex internal stress condition. They perform and interact at multi-length-scales from intense diversified dislocation trapping, massive stacking-fault proliferation, 9R-phase-assited nano-twinning, self-buffering shear bands to ever-intensified hetero-deformation-induced hardening. These scenarios even create superior, strain-rate-tolerant dynamic properties far exceeding conventional homogeneous-structured counterparts. Dendrites exist ubiquitously, yet generally undesirable, in metallic materials, whereas our 'bioinspired, heredity-derived' strategy counterintuitively utilizes them, realizing unprecedented high figure-of-merit multifunctionality. [ABSTRACT FROM AUTHOR]

The aging precipitation behavior of 6061 aluminum alloy that underwent iron casting and water-cooled copper casting and 6061 aluminum with Mn and Zr elements added was studied. Firstly, the hardness curves, tensile properties, and fracture morphology of four aging alloys—6061 (iron mold casting), 6061 (water-cooled copper mold casting), 6061-0.15Mn-0.05Zr (iron mold casting), and 6061-0.15Mn-0.05Zr (water-cooled copper mold casting)—were studied. The results of the aging hardness curve show that the aging precipitated phase of the 6061 alloy cast with a water-cooled copper mold is dispersed. The addition of Mn increases the amount of coarse inclusion α-(AlMnFeSi) in the alloy, resulting in a decrease in the age hardening property. The addition of Zr is related to the nucleation and growth of the G.P. region in the early aging period, mainly changing the formation rate and quantity of the G.P. region, leading to the advancement of peak aging and an increase in hardness. After the G.P. region gradually transforms into the β phase, the hardness of the alloy increases with the increase in the volume fraction of the β phase. When the β″ phase is coarsened to the point where the fault line can be bypassed, the transitional metastable β′ phase begins to precipitate, and the coherent distortion around it weakens, indicating over-aging. Finally, the equilibrium phase Mg2Si is formed. The results of the tensile tests indicate that the tensile strength and yield strength of the 6061-0.15Mn-0.05Zr alloy produced by water-cooled copper casting after aging are 356 Mpa and 230 Mpa, respectively. These values are 80 MPa and 75 MPa higher, respectively, than those of the 6061 aluminum alloy produced via iron casting. However, the elongation is by 5%. The fracture morphology of the tensile sample of the aging alloy shows that dislocation slip in the alloy results in dislocation plugging, stress concentration, and the initiation of crack cleavage on the surface. The fracture of the water-cooled copper mold-casting alloy is a ductile fracture of the microporous aggregation type, and the macroscopic fracture exhibits an obvious "neck shrinkage" phenomenon. The fracture analysis is consistent with the mechanical properties. The DSC curve shows that there is no enrichment process of solute atoms during the heating process, and the aging precipitation process after homogenization is as follows: G.P. zone → β″ phase → β′ phase. The aging precipitation process of the water-cooled copper casting alloy after homogenization treatment is as follows: β″ phase → β′ phase (no precipitation in the G.P. zone was observed). The results of the differential scanning calorimetry (DSC) analysis show that the main strengthening phase in the experimental alloy system is the β″ phase. The activation energies for the β″ phase precipitation were calculated and found to be 147 KJ/mol, 217 KJ/mol, 185 KJ/mol, and 235 KJ/mol, respectively. Additionally, a kinetic equation for the β″ phase precipitation during alloy aging was fitted. [ABSTRACT FROM AUTHOR]

The current review work studies the adiabatic shear banding (ASB) mechanism in metals and alloys, focusing on its microstructural characteristics, dominant evolution mechanisms and final fracture. An ASB reflects a thermomechanical deformation instability developed under high strain and strain rates, finally leading to dynamic fracture. An ASB initially occurs under severe shear localization, followed by a significant rise in temperature due to high strain rate adiabatic conditions. That temperature increase activates thermal softening and mechanical degradation mechanisms, reacting to strain instability and facilitating micro-voiding, which, through its coalescence, results in cracking failure. This work aims to summarize and review the critical characteristics of an ASB's microstructure and morphology, evolution mechanisms, the propensity of materials against an ASB and fracture mechanisms in order to highlight their stage-by-stage evolution and attribute them a more consecutive behavior rather than an uncontrollable one. In that way, this study focuses on underlining some ASB aspects that remain fuzzy, allowing for further research, such as research on the interaction between thermal and damage softening regarding their contribution to ASB evolution, the conversion of strain energy to internal heat, which proved to be material-dependent instead of constant, and the strain rate sensitivity effect, which also concerns whether the temperature rise reflects a precursor or a result of ASB. Except for conventional metals and alloys like steels (low carbon, stainless, maraging, armox, ultra-high-strength steels, etc.), titanium alloys, aluminum alloys, magnesium alloys, nickel superalloys, uranium alloys, zirconium alloys and pure copper, the ASB propensity of nanocrystalline and ultrafine-grained materials, metallic-laminated composites, bulk metallic glasses and high-entropy alloys is also evaluated. Finally, the need to develop a micro-/macroscopic coupling during the thermomechanical approach to the ASB phenomenon is pointed out, highlighting the interaction between microstructural softening mechanisms and macroscopic mechanical behavior during ASB evolution and fracture. [ABSTRACT FROM AUTHOR]

The alloys of the aluminum bronze system contain 5–14wt% Al that can be heat treated giving as result of different microstructures that were characterized by optical microscopy and scanning electron microscopy. This work aimed at investigating the influence of the microstructures of a Cu-9Al-3Ag alloy obtained after normalizing and annealing heat treatments, on the corrosion behavior in a saline medium containing 0.5 M sodium chloride, NaCl. The corrosion effect on the phases compounding the overall microstructures as result of immersing the samples in the corrosive medium was evaluated using cyclic voltammetry, potentiodynamic polarization curves, and electrochemical impedance spectroscopy. The results showed that normalizing and annealing heat treatments redefined the distribution of the α phase and, in addition led to formation of proeutectoid pearlite (α + γ2), which is a microstructural constituent configured similarly to that present in diverse carbon steels, though in this case displaying a sequence of alternate lamellae of α and γ2, respectively. From the results of the linear polarization plots, the maximum anodic potentials became apparent, just like the regions where the trend of the graph gave the impression that passivation were to gain control. Likewise, the Tafel plots and impedance tests evidenced that the as-cast and normalized samples exhibited a better resistance to corrosion, at variance with the results of the annealed sample. [ABSTRACT FROM AUTHOR]

The Cu–1.1 wt% Hf–0.1 wt% Si alloy containing various precipitates is studied as a novel precipitation‐strengthened alloy with high strength and high electrical conductivity. The Cu–Hf–Si alloy prepared by solution, cold rolling, and aging processes exhibits a hardness of 238.92 HV, a tensile strength of 691.01 MPa, a breaking elongation of 15.09%, and an electrical conductivity of 62.34% International Annealed Copper Standard. The optimal peak aging parameter for Cu–Hf–Si alloy is 430 °C for 90 min. The precipitation of Hf and Si atoms from the Cu matrix is helpful to enhance the electrical conductivity. The precipitation of Hf can produce fibrous Guinier Preston zone and γ' precipitate, as well as spherical Cu10Hf7 phases. In addition, the coprecipitation of Si and Hf can also produce Hf3(Cu2Si)2 and HfCuSi phases. The high strength of Cu–Hf–Si alloy is mainly due to the multiprecipitates synergistic strengthening. [ABSTRACT FROM AUTHOR]

Sketching a proper catalytic system with supplementary attributes, containing easy separation, wide surface area, supreme loading capacity, and fantastical electronic attributes, proposes an encouraging direction for efficiently using nanostructures for various applications. However, the capability to adjust the nano‐measure bimetallic particles is an adjustment for attaining superb performance in the catalytic field. Herein, an environmentally benign approach was developed for immobilizing and anchoring Pd‐Cu alloy nanoparticles on murexide (MX)‐functionalized carbon nanotubes (CNTs). Afterward, the catalytic activity of Pd2‐Cu3@MX/CNT was studied in synthesizing 2,3‐dihydro quinazoline‐4(1H)‐ones and carbon–carbon coupling reactions at sustainable reaction conditions under ultrasound irradiation. The results demonstrated that high‐affinity MX ligand and porous CNT structures than the adsorption of Pd–Cu had a unique designation in the high‐range constancy of the alloy nanoparticles and following catalytic activity. In addition, ultrasound irradiation got electrons of Pd–Cu alloy nanoparticles agitated, constructing a synergic efficacy between Cu and Pd metals for synthesis and coupling reactions. Our study represents that the designed catalyst is green, recyclable, and most suitable, providing new intuition into in high‐range constancy of bimetallic nanoparticles for broad applications. [ABSTRACT FROM AUTHOR]

Ginalski‐type E5 button spurs made from a Cu alloy are a characteristic attribute of the Middle Roman period in barbarian Europe. The find of part of a mould made of non‐ferrous metal at the Luleč site in the district of Vyškov, Czech Republic, provided key evidence for explaining the issue of their production. The discovery of this unique artefact showed that based on current knowledge, the spurs made from a Cu alloy were also produced in the Middle Danube region and not only in Northeast Europe as had previously been thought. [ABSTRACT FROM AUTHOR]

A nickel-based copper alloy known as Monel-400 is extensively applied in many industries including aerospace, marine engineering, and nuclear power generation, owing to its exceptional characteristics such as extreme tensile strength and toughness, excellent corrosion resistance, and the ability to retain shape even at extremely high temperatures. Traditional methods of drilling Monel-400 alloy are difficult due to quick tool wear and poor surface polishing, resulting in expensive machining costs. In this study, a technique called heat annealing was implemented to externally heat-treat the Monel-400 alloy material before the drilling process. Cutting force, surface roughness, and tool wear were used as the responses to investigate the effect of heat annealing and the drilling parameters on the machinability of Monel-400. The results revealed that the cutting force (Fz) and surface roughness (Ra and Rt) could be reduced by 33%, 31%, and 25%, respectively, after annealing at 700 °C compared to the results of the drilled Monel-400 at room temperature. It can be observed that the maximum improvement can reach 42% of Fz, 35% of Ra, and 59% of Rt while annealing Monel-400 at 1000 °C. A significant reduction was observed in the tool wear for machining the annealed material, which minimized the tooling and overall machining cost. Regarding the effects of the drilling process on the considered responses, the results revealed that the spindle speed has a greater effect on the cutting force, whereas the feed rate has the most significant effect on Ra. The significance of the drilling input parameters on the outputs is determined by analysis of the main effect plots and surface plots. Subsequently, the multi-objective genetic algorithm (MOGA) is used to identify the optimal parametric conditions for minimizing the cutting force and surface roughness of the drilled holes. The optimized values achieved via multi-objective optimization are the cutting force, Fz = 388–466 N, and the surface roughness, Ra = 0.17–0.19 μm and Rt = 3–3.5 μm, respectively. [ABSTRACT FROM AUTHOR]

The present work is devoted to the electrochemical deposition of thin CoSe films and study of the influence of various factors on the composition of the resulting film. It was established that during the deposition of both individual components and in their joint presence, the electroreduction potentials (Se, Co and CoSe) are respectively equal to 0.35, -0.2, 0.23 V. Anodic dissolution of CoSe is observed at a potential of 0.75 V. The electrochemical reduction of selenium and cobalt occurs in 2 stages. The results demonstrated that both the temperature and the electrode material have a significant effect on the kinetics of CoSe electrodeposition. At temperatures above 600C, the quality of the resulting films deteriorates. High-quality crystalline films with high adhesion surface are obtained in the temperature range of 25-600 C. Pt, Ni were taken as a cathode material and Pt served as the anode. The optimal electrolyte composition and electrolysis mode for obtaining thin CoSe films close to the stoichiometric composition were also determined. 0.01 M H2SeO3, 0.1 М CoCl2, 100 ml H2O, i=0.2-0.4 mА/sm2, Т=25-600С, Cathode - Pt, Ni. anode Pt. [ABSTRACT FROM AUTHOR]

Single-pressure and ultrasonic action have their own unique advantages in the treatment of metal melts. When the two are combined into a composite field, the advantages of a single physical field can be fully utilized. So, the cavitation and acoustic streaming effects characteristics of an Al-5.0Cu alloy treated under different coupling process parameters, related to applied extrusion pressure and ultrasonic vibration, were analyzed by combining numerical simulation and experimental verification. The simulation results were experimentally verified by quantitative analysis of the microstructure, the melt, and its macro characteristics. The results show that the closing time t decreases with an increase in the extrusion pressure. In addition, when the ultrasonic power and extrusion force are increased simultaneously (100 MPa and 1 kW), the average grain size and the proportion of columnar grains reach the ideal effect. The influence of pressure parameters is greater, which will also lead to an increase in the proportion of columnar crystals. By optimizing the parameters, the grain size can be further reduced, the proportion of columnar crystal structure can be reduced, and fine and uniform equiaxed crystal structures can be easily obtained. [ABSTRACT FROM AUTHOR]

This study investigated the allowability of materials in the laser powder melting process, with a focus on powder mixing as a means of adjusting the material composition quickly and cost-effectively. By mixing different powders, a desired alloy can be created during additive processing without the need to produce new powder, which can be expensive. However, one of the main challenges in this process is the segregation of powders, which can lead to non-homogeneous alloys. To address this challenge, the study examined the use of a single component 316L mixed with 1% and 5% copper powder in the additive processing. The results showed that homogeneous components with a uniform and targeted copper content could be produced. However, the mechanical-technological properties of both alloys were lower than those of 316L in situ. To optimize and extend this study, further investigation could be conducted to improve the homogeneity of the powder mixture and to enhance the mechanical-technological properties of the alloys produced. This could involve exploring different alloy designs, optimizing the laser powder melting process parameters, and using advanced characterization techniques to gain a deeper understanding of the microstructure and properties of the alloys. By addressing these challenges, the laser powder melting process could become an even more promising method for producing customized alloys with tailored properties. [ABSTRACT FROM AUTHOR]

This study explored the nitrate reduction by Al-Fe alloy. The nitrate conversions of fresh, 30-day and 90-day alloys were 78.1%, 42.8% and 9.5%, respectively. Water activation promoted the reducing ability of the alloy (98% nitrate removal), which was higher than that of copper deposited alloy (66%) and H2-reducing/acid/alkali/Cl− activated alloy (no enhancement). The effects of pre-treatments on the surface O fraction changes confirmed the activation results. With increased Fe:Al mass ratio in the alloy, nitrate conversion initially decreased and then increased again, verifying the proposed electron-donator activity of Al or Fe in alloys. Al-Fe30 had the highest NO3− conversion and Al13Fe4 content, so Al-Fe30 was selected. Significant differences in conversion were observed in alloy usages of 5–10 and 15–30 g/L. High reduction performance (nitrate below the detection limit and 19.1% N2 selectivity) was achieved under the optimal conditions: 15 g/L Al-Fe30, 150 min reaction and without pH adjustment. The rate constants of nitrate removal, nitrogen generation and ammonia generation were k1 = 1.43 × 10−2, k2 = 3.41 × 10−2 and k3 = 10.58 × 10−2 min−1, respectively. The value of (k2 + k3)/k1 was 10, indicating that the conversion of nitrate into nitrite was the rate-determining step. The repetition reaction was performed, and the rate constant decreased as the reaction step was repeated. [ABSTRACT FROM AUTHOR]

The effect of copper content on the microstructure and properties of an aluminum copper alloy containing lanthanum was studied by adding 0.5 wt% lanthanum and different contents of copper to the 2A12 alloy. We used a universal testing machine, Brinell hardness tester, and friction and wear testing machine to test the mechanical properties of the alloy. The microstructure and phase composition of the alloy were analyzed using scanning electron microscopy, energy dispersive spectroscopy, and X-ray diffraction. The results show that, after adding La and Cu, the alloy grain is refined, and the fracture mode changes from dissociation fracture to quasi dissociation fracture. A new phase containing La accumulates at the grain boundary. If the amount of Cu added is too large, the tendency for hot cracking increases, which can easily lead to the formation of voids or even cracks. The tensile strength and hardness of the cast alloy significantly increase with the increase in Cu addition. In the range of adding 2 wt% to 5 wt% Cu, the tensile strength and hardness of the cast alloy increases by approximately 12% and 17.84%, respectively, compared with the original alloy. With the increase in Cu addition, the elongation of the alloy first increases and then decreases, reaching its maximum value when Cu addition is 3 wt%. Adding Cu is beneficial for improving the wear resistance of the alloy. When the addition of Cu is 3 wt%, the alloy has the best wear resistance and minimum wear amount. This is due to the enrichment of La and Cu at the grain boundaries, forming new La phases or other phases with higher hardness, which changes the properties of the alloy. It shows that the content of Cu in the 2A12 alloy can be increased to 7-8% with the increasing of additional rare-earth elements, and a new Al-Cu (7 wt% to 8 wt%)-Mg (1.2 wt% to 1.8 wt%)-Mn (0.3 wt% to 0.9 wt%)-La (0.5 wt%) alloy, in which tensile strength, hardness, and elongation of the alloy are increased by 8.1%, 16%, and 79.1%, respectively, can be formed. In addition, the wear resistance of Al-La alloys also improves significantly with the addition of copper content. The coefficient of friction is reduced by 68% compared with no copper addition. [ABSTRACT FROM AUTHOR]