Copper-based Alloys Research Articles

Impact of Boron Nitride(H) reinforcement on the properties of 5.8% copper-based aluminium alloy surface composite done by friction stir processing

ABSTRACT Numerous experiments and research is underway within the realm of aluminium metal matrix surface composites (MMSCs). This material has been applied in various marine, and aerospace industries, on account of its remarkable mechanical properties and desirable weight to strength ratio. The current study is focused on the synthesis of surface composites comprising of BN(H) reinforced 5.8% Cu aluminium alloy matrix composites. Boron Nitride(H) was reinforced on the surface of the Aluminum Alloy by FSP. Grooves were machined on the surface of the matriux and compacted with reinforcement particles. The wear rate, tensile behaviour, and microhardness were evaluated for the fabricated surface composites. The microstructural analysis was done via EDAX and FE-SEM to establish the presence of the reinforced particles. The tensile strength increased marginally with an increase in microhardness and reduction in elongation percenatge. The wear morphology aided in identifying the various wear mechanisms observed.

Shifting techniques in perforating animal teeth and metal objects. Some examples from Early Bronze Age contexts

This paper addresses shifting techniques between manufacturing two types of raw materials. On the one hand, they are copper-based alloys that were processed in the Early Bronze Age (c. 2300-1600 BCE) only by a few craftspersons, and, on the other hand, well-known and commonly processed animal hard tissues. At least one technique we observed on the metal objects originates from those of working with animal hard tissues, while the other one can be found in already published evidence. Application of techniques known from bone and antler processing in metallurgy indicates cross-craft communication and learning processes.

Operational Properties of Metal–Metal Friction Members with Surface Layers Modified by Copper-Based Alloy

Operational Properties of Metal–Metal Friction Members with Surface Layers Modified by Copper-Based Alloy

Correlative analysis of advanced microscopy techniques for metallography and corrosion microstructures of bronze phoenician coins

Correlative microscopy stands out for its ability to concurrently acquire and analyze various data types in a multimodal and multiscale environment, enabling precise localization of specific areas within samples and enhancing the accuracy and relevance of analyses. This approach showed promise in revealing the metallurgical history of ancient coins. This article focused on composition, microstructure, and manufacturing process of Phoenician-Punic copper-based alloy coins (5th–4th century BCE). The four coins studied by correlative light and electron microscopy, μ-Raman spectroscopy, and X-ray Microscopy exhibited notable differences in elemental composition and microstructures. These variations are attributed to their origin from casting, followed by striking, and subsequent recrystallization due to a more intricate corrosion process.

A bimodal and heterogeneous laminate structure with alternately distributed copper-base and nickel-base alloys via multi-material laser powder bed fusion (MM-LPBF) additive manufacturing

A micro-laminated bimodal heterostructure with alternately distributed copper-base and nickel-base alloys was additively manufactured via the multi-material laser powder bed fusion (MM-LPBF) technique. The high melting point elements such as nickel act as the heterogeneous nucleation sites for the copper melt, promoting the generation of ultrafine grains and forming a multi-layered structure with alternating coarse and fine grains. The differentiated grain size, shape and orientation in the bimodal heterostructure lead to the diversity of deformation mechanisms in different localized areas, which helps to achieve the internal stress gradient distribution and plastic deformation harmonization, thereby overcoming the strength-ductility trade-off for the overall structure. This work provides a novel fabrication path and experimental basis for understanding bimetallic laminated heterostructures.

Revisiting the role of foreign atoms in [formula omitted] reduction on CuSn single-atom surface alloys

The electrochemical CO2 reduction is a promising process for capturing the emitted carbon dioxide by converting CO2 into value-added chemicals. Although copper-based catalysts have a unique ability to produce multi-carbon products, they suffer from poor selectivity. Copper-based alloys and, in particular, single atom alloys, hold promise for fine-tuning the selectivity of CO2 reduction reaction. In this study, we applied the grand canonical density functional theory in combination with the implicit solvent to model CO2 electroreduction with the formation of CO and HCOO− on copper and highly diluted copper-tin alloys. We demonstrate that the insertion of a substitutional Sn atom introduces a destabilization effect for all intermediates and completely disrupts the adsorption positions of the CO, H, and H/CO2 co-adsorption. However, the influence of Sn on intermediate adsorption energies is primarily localized in its immediate vicinity. We demonstrate that sparsely distributed single Sn atoms do not account for the experimentally observed significant reduction in formate and hydrogen generation across the entire Sn-substituted Cu surface. This discrepancy underscores the need to reevaluate the proposed surface structure and the nature of the active sites on CuSn single-atom surface alloys.

The electrochemical corrosion behavior and antibacterial properties of Cu-xFe alloy

Copper-based alloys have garnered significant attention for their potential in antimicrobial applications aimed at mitigating medical-related infections. Nonetheless, the alloying elements in conventional copper alloys frequently exhibit biotoxicity. This study explored the corrosion behavior, antimicrobial activity, and ion release of Cu–Fe alloys with varying iron contents and aging treatment. The results indicate that increasing the iron content in Cu–Fe alloys and applying appropriate aging treatment can enhance both the antibacterial efficiency and corrosion rate. Transmission electron microscopy (TEM) observations revealed a corrosion mechanism in which dispersed iron phases act as nucleation sites. These nanoscale precipitates increase the Cu/Fe interfacial area, thereby promoting ion release at the interface. Furthermore, in-situ scanning electron microscopy (SEM) revealed that corrosion products are more likely to detach in iron-rich segregated areas, which effectively promotes the sustained release of copper ions.

Investigating the process parameter window for laser powder bed fusion of copper chrome zirconium

ABSTRACT Copper-based alloy UNS C18150 has become an attractive material for laser powder bed fusion (LPBF) processing. However, the complexity of LPBF mandates that unique process parameters be devised for each alloy as these are highly sensitive to material chemistry. This work aims to clarify the general boundaries of the process window for the most influential parameters alongside an exploration into the effects of scan strategy on the density. A series of statistical design of experiments were utilised to model density as a response and predict process parameters that would result in minimised residual porosity. Using optimised parameters, specimen with up to 99.1% of theoretical density were produced, and a window of process parameters was established that yielded similarly dense products. Post-build aging of the LPBF parts was also explored. Here, direct aging of the as-built product at 390°C for 100 h resulted in a peak hardness of 83.3 ± 0.6 HRB.

Promising urea electrosynthesis by C-N coupling on copper-based single-atom alloys

Electrochemical synthesis of urea holds a significant importance in the energy landscape, however, the lack of efficient electrocatalysts is the main bottleneck. In this study, 40 single-atom alloys (SAAs) based on Cu(100) and Cu(111) surfaces have been systematically investigated as electrocatalysts for CO2 and N2 co-reduction to produce urea utilizing first-principles calculations. A promising single N and C coupling pathway is uncovered on Cu-based SAAs, besides conventional NCON, CO2, COOH, and CO pathways. CuHf(100) displays a high efficiency in N-N decomposition, C-N coupling, and low reaction limiting potential. Furthermore, CuHf(100) and CuSc(100) have been identified as superior electrocatalysts for efficient urea electrosynthesis. This work provides potential reaction mechanisms with specific single N species, but also a universal strategy for the surface engineering of transition metal-based catalysts in electrocatalytic urea synthesis reactions.

Structural analysis of selective laser melted copper-tin alloy

Additively manufactured complex geometries from copper alloys with high thermal and mechanical properties have drawn the attention of researchers. The present contribution explores the additive manufacturing (AM) of copper-based alloys from powder particles intended for heat sink and heat exchange applications. Selective laser melting (SLM) parameters featuring low laser beam power (160 W), moderate scanning speed (320 mm/s), and high energy density (200 J/mm³) were employed to fabricate dense components from CuSn10 particles. The present work deal with structural analysis and precision investigation of microfabrication, particularly in Struts, Tubes, and Fins. Mechanical properties (compression and hardness) for Strut structure, differential pressure evaluations for Tube structure, and analyses of thermal and electrical conductivities for Fin structure were investigated. The results showed an improvement in strength compared to those of pure copper, facilitating ease of AM. The obtained results affirm the feasibility of AM, demonstrating the successful creation of complex and combined solid-porous structures using SLM process from Cu alloys. A comprehensive structural investigation and characterization of the Cu–Sn alloy is presented here, aiming to establish a standardized approach for analysing Cu alloys. The results indicate that small-scaled structures fabricated via CuSn10 alloy exhibits a thermal conductivity of 34.3 W·m⁻¹·K⁻¹, an electrical conductivity of 4.72×10⁶ S/m, a hardness of 119 HV-50, a uniform surface roughness of 6 µm, and can withstand a force loading of 1 kN.

Spark Plasma Sintering of Cu-Ti-Ni Ternary Alloy: Microstructural, Thermal and Electrical Properties

High strength and good conductivity are both critical parameters for copper-based alloys for electrical and other technological applications. This study is aimed to produce copper alloys and metal matrix composites (MMCs) with enhanced physical properties. Cu-Ti-Ni ternary alloys and MMCs samples were sintered at 600 to 700°C using spark plasma sintering (SPS), with a heating rate of 100°C/minutes, uniaxial pressure of 50 MPa, and a holding time of 10 minutes. Scanning electron microscopy (FE-SEM) was used to examine the microstructure, while the relative densities of the composites were obtained via the Archimedes Principle method. A four-point probe and differential thermal analyzer (DTA) obtained electrical resistivity and thermal properties. The results indicated that the sample density nominally increases with sintering temperature but decreases with aluminium nitride additions. The electrical conductivity increases with the sintering temperature and AlN nanoparticle content. Distinct phase changes were observed from the DTA, occurring with the addition of AlN.

Evolution mechanism of rapid solidification microstructure of an undercooled copper-based single phase alloy

Using undercooling technology combined with melt purification of glass and recirculation overheating, different undercoolings were successfully obtained for Cu60Ni38Co2 alloy samples. Applying high speed photography technique, the physical process of undercooled solidification was observed and relationship between undercooling and solidification rate was analyzed. Experimental results indicate the critical undercoolings exist in the structure evolution process. Electron backscatter diffraction (EBSD) analysis was applied to characterize the Cu60Ni38Co2 alloy sample with a maximum undercooling of 255K, revealing grain orientation and the corresponding orientation difference distribution. In addition, transmission electron microscopy (TEM) showed high density dislocation networks. Combining EBSD and TEM data analysis, an important conclusion was drawn: recrystallization is the main factor for grain refinement at high undercooling. This finding is of great significance for a deeper understanding of the structure evolution in the physical process of undercooled alloys.

Effect of Hydrogen Charging on the Mechanical Properties of High-Strength Copper-Base Alloys, Austenitic Stainless Steel AISI 321, Inconel 625 and Ferritic Steel 1.4511

Hydrogen embrittlement (HE) poses the risk of premature failure for many metals, especially high-strength steels. Due to the utilization of hydrogen as an environmentally friendly energy source, efforts are made to improve the resistance to HE at elevated pressures and temperatures. In addition, applications in hydrogen environments might require specific material properties in terms of thermal and electrical conductivity, magnetic properties as well as corrosion resistance. In the present study, three high-strength Cu-base alloys (Alloy 25, PerforMet® and ToughMet® 3) as well as austenitic stainless AISI 321, Ni-base alloy IN 625 and ferritic steel 1.4511 are charged in pressurized hydrogen and subsequently tested by means of Slow Strain Rate Testing (SSRT). The results show that high-strength Cu-base alloys exhibit a great resistance to HE and could prove to be suitable for materials for a variety of hydrogen applications with rough conditions such as high pressure, elevated temperature and corrosive environments.

Metal Fragments of Roman Pipes from Pompeii: Investigations on Copper-Based Alloys, Corrosion Products, and Surface Treatments

This work reports the study of metal fragments from Roman pipes excavated from the archaeological site of Pompeii and currently preserved in the deposits of the National Archaeological Museum of Naples (MANN). The Roman pipe, called the tibia, is a reed wind musical instrument similar to the Greek aulos. It can be made of wood, bone, and/or metal. Materials consisting of metal Cu-based alloys were excavated from archaeological burial environments. This research aims to identify the composition of the alloys, characterize the corrosion patinas, and identify any ancient surface treatments on the fragments. Non-invasive and micro-invasive techniques were used to achieve this aim, i.e., optical microscopy, Raman spectroscopy, attenuated total reflectance Fourier-transform infrared spectrophotometry, scanning electron microscopy, and energy dispersive spectrometry. This research contributes to a deeper understanding of the materials and manufacturing techniques used for these instruments, as well as the degradation processes occurring over the centuries.

Antibacterial property alterations induced by low zinc content in laser-structured brass

Brass, along with other copper-based alloys, exhibits advantageous antibacterial properties that can be further enhanced by altering the surface topography to increase bacterial adhesion. This enhancement is achievable through a higher contact area created by precise periodic structures, each approximately the size of a single bacterial cell. One method for generating these structures is ultrashort pulsed direct laser interference patterning (USP-DLIP). However, this process may induce chemical alterations in addition to topographical changes, depending on the substrate’s composition. To mitigate unfavorable chemical alterations, brass with a 15% zinc content was selected for this study. The antibacterial effectiveness of the modified surfaces was tested against Escherichia coli, providing initial insights into the interaction between bacteria and the substrate. The results indicate that modified brass with a 15% zinc content shows improved antibacterial activity. Overall, this research demonstrates that by modifying a surface with the appropriate chemical composition, effective bacterial elimination through contact can be achieved.

L-arginine-etched nickel-silver electrocatalyst for low-potential hydrogen evolution

The oxidation of formaldehyde at low potentials to achieve anodic hydrogen production is a crucial focus of current research. Copper-based alloys are prominent electrocatalysts in these reactions but face long-term stability challenges and are susceptible to CO intermediate poisoning. A novel approach that utilizes L-arginine in the surface modification of nickel foam substrates has been developed, enabling the highly dispersed deposition of silver catalysts on the substrates as sub-nanometer particles. This modified electrocatalyst allows formaldehyde oxidation and water electrolysis at a minimal potential of 0.32 VRHE and bipolar hydrogen production with near 100% Faradaic efficiency. This surface modification of substrate material provides a new approach to the design of electrodes.

Manufacturing of Bricks by using Waste Foundry Sand

The foundry is an industrial sector where various iron, scrap steel, and ferroalloys are melted down in arc furnaces or cupolas, shaped in sand, ceramic, or metal moulds, and the cast, steel, nodular, and tempered foundry products needed in industry are produced as raw or processed materials. Especially in establishments such as factories and workshops that produce parts of the automotive, construction, and machine and in steel industry, foundry sand is used to mould foundry products (iron-steel industry and aluminium- and copper-based alloys).Foundry sand is used to prepare metal foundry moulds. For 1 ton of production, 4-5 tons of sand is required. This ratio may be changed based on the type of the metal that needs to be casted, part size, and moulding technique. Sands that contain more than 90% of silica and 7–15% clay (bentonite or kaolinite clay) and have a sintering temperature of over 1500°C are defined as foundry sands. Foundry sand disposal is a herculean task for the industrial sector in today’s scenario. In order to overcome this problem to some extent, it is required to convert it into some useful products. Hence, this project gains its importance for the effective utilization of foundry sand into foundry sand bricks

Characterization of CuAg Alloys with Low Ag Concentrations.

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.

Archaeometallurgical characterization of Late Antique personal adornments. The necropolis of Cortijo del Chopo (Granada, Spain)

Objects of personal adornment from Late Antiquity have been extensively studied in the Iberian Peninsula since the 19th century, when the first funerary contexts from that period began to come to light. However, only partial information was available with regard to their production process and chemical composition. This came from the archaeometallurgical studies carried out on funerary assemblages from central and northern Iberia. In order to obtain a more complete picture, a set of 80 copper-based alloy objects were analysed, most of ornaments and parts of them, from the necropolis of Cortijo del Chopo (Granada), in southeastern Spain. The results from the portable X-ray fluorescence reveal the presence of a wide variety of alloys and confirm the practice of recycling metals to make the items, a characteristic of the metallurgy of the period. Lead isotope analysis provide evidence of a local production of brass objects with a high Zn content, similar in appearance to gold.

Effect of pulse time (Ton), pause time (Toff), peak current (Ip) on MRR and surface roughness of Cu–Al–Mn ternary shape memory alloy using wire EDM

Shape memory and super elasticity are two outstanding properties of Cu–Al–Mn SMAs together with additional copper-based shape memory alloys that make them superior to NiTi alloys. It's quite hard to machine Cu–Al–Mn SMA. The machinability properties of Cu–Al–Mn SMAs during Wire Electrical Discharge Machining (WEDM) were experimentally investigated using molybdenum wire as the electrode material. Material Removal Rate (MRR) and Surface Roughness (SR) are two machining qualities that are studied in relation to the combinational values of pulse time (Ton), pause time (Toff), and peak current (Ip), which are selected as the changeable input process factors. From the experimental investigation, it was found that both MRR and Ra values were increased with an increase in pulse on time(Ton), pulse off time(Toff), and peak current (IP)values. Because the wire electrode contains maximum current under these conditions, it is easy to remove more material at the tool and work material interface, resulting in moderate surface finish. Surface quality was higher on samples machined at low energy input than it was on samples machined at high energy input. This SEM micrograph clearly shows that a lower pulse on time produces a superior surface quality.SEM images and the analysis of the machined surface morphology on the surface of the CAM7 alloy clearly showed that the machined surface of the alloy had a lower surface roughness value at a lower Ip-2A and was associated with a higher surface roughness value at a higher Ip-6A, as well as a lot of uncleared debris and blow holes.