Plated Copper Alloy Research Articles

New results on horse trappings from the Hunnic-period Carpathian Basin based on non-destructive archaeometric analyses

Objects manufactured from pressed gold, gilded silver or copper alloy plates are characteristic assemblages from the Late Hunnic period (5th century AD, 420/430). In this study, horse trappings that belong to the ‘pressed gold plate horizon’ from three archaeological sites in the Carpathian Basin (Léva, Nyíregyháza-Oros and Pécsüszög) were analysed non-destructively by using a handheld X-ray fluorescence spectrometer. The main aims were to determine the chemical composition and the gilding technique used, and to attempt to prove whether the groups in an assemblage are from the same set. The results of the chemical analyses give us the opportunity to confirm whether damaged or presumably lost objects of an assemblage were replaced or repaired. According to the results obtained, the objects were manufactured from gold (Pécsüszög), gilded silver (Nyíregyháza-Oros) or gilded unalloyed copper plates (Léva). Later, replacements can be distinguished based on their chemical composition and manufacturing quality. Two types of gilding were observed: fire gilding with the presence of mercury (Léva), and leaf gilding (Nyíregyháza- Oros).

Detectable Depth of Copper, Steel, and Aluminum Alloy Plates with Pulse-Echo Laser Ultrasonic Propagation Imaging System

Pulse-echo laser ultrasonic propagation imaging is a nondestructive testing technique developed for composite materials and aluminum alloys used in aerospace. Although this method has been in usage for a considerable time, information of the detectable depth and the relationship between ultrasonic frequencies and the acoustic properties of metals is not readily available. Therefore, we investigate the A-scan and C-scan ultrasonic testing data of aluminum alloy, hot rolled steel, stainless steel, and copper alloy, which are used in aircraft bodies, frameworks, and gas pipelines. Experiments are performed with the pulse-width and excitation laser power fixed at 32 ns and approximately 4 W, respectively. The metal specimens include 24 artificial cylindrical defects with a diameter of 5 mm, located at depths of 1–12 mm on the front surface. The A-scan and C-scan data obtained at room temperature indicate the detectable depth for metals via the pulse-echo laser ultrasonic propagation imaging technique.

Evaluation of copper alloys for reducing infection by methicillin resistant Staphylococcus aureus and vancomycin resistant Enterococcus faecium in intensive care unit and in vitro.

Background/AimsMulti-drug resistant pathogens are increasing among healthcare-associated infections. It is well known that copper and copper alloys have antimicrobial activity. We evaluated the activity of copper against bacteria in a hospital setting in Korea.MethodsThis study was conducted in a laboratory and medical intensive care unit (ICU). Methicillin resistant Staphylococcus aureus (MRSA) and vancomycin resistant Enterococcus faecium (VRE) were inoculated onto copper, copper alloy and stainless steel plates. After 24 hours of incubation, colony-forming units (CFU) were counted in the laboratory. Two similar rooms were chosen in the ICU; one room had copper-containing surface, and the other room contained items with a stainless steel surfaces. Items were sampled weekly for 8 weeks when the rooms were not crowded and when the rooms were busier with healthcare workers or visitors.ResultsIn vitro time-kill curves showed copper or, a copper alloy yielded a significant reduction in MRSA and VRE CFUs over 15 minutes. Upon exposure to stainless steel plates, CFUs were slowly reduced for 24 hours. In vivo, MRSA CFUs were lower in rooms with copper-containing surfaces compared with controls, both after cleaning and after patients had received visitors (p < 0.05). Analysis of VRE revealed similar results, but VRE CFUs from copper-containing surfaces of drug carts in the ICU did not decrease significantly.ConclusionsCopper has antimicrobial activity and appears to reduce the number of multi-drug resistant microorganisms in a hospital environment. This finding suggests the potential of the use of copper fittings, instruments and surfaces in hospital.

Creep-fatigue life prediction of perforated copper-alloy plate by using digital image correlation method

Creep-fatigue life prediction of perforated copper-alloy plate by using digital image correlation method

Simulation Study on Weld Formation in Full Penetration Laser + MIG Hybrid Welding of Copper Alloy.

Considering the coupling of a droplet, keyhole, and molten pool, a three-dimensional transient model for the full penetration laser + metal inert gas (MIG) hybrid welding of thin copper alloy plate was established, which is able to simulate the temperature and velocity fields, keyhole behavior, and generation of the welding defect. Based on the experimental and simulation results, the weld formation mechanism for the hybrid butt welding of a 2 mm-thick copper alloy plate was comparatively studied in terms of the fluid dynamic feature of the melt pool. For single laser welding, the dynamic behavior of liquid metal near the rear keyhole wall is complex, and the keyhole has a relatively drastic fluctuation. An obvious spattering phenomenon occurs at the workpiece backside. Meanwhile, the underfill (or undercut) defect is formed at both the top and bottom surfaces of the final weld bead, and the recoil pressure is identified as the main factor. In hybrid welding, a downward fluid flow is strengthened on the rear keyhole wall, and the stability of the keyhole root is enhanced greatly. There are large and small clockwise vortexes emerging in the upper and lower parts of the molten pool, respectively. A relatively stable metal bulge can be produced at the weld pool backside. The formation defects are suppressed effectively, increasing the reliability of full penetration butt welding of the thin copper alloy plate.

Investigation of a simulated Chinese jade and bronze dagger-axe by neutron radiography and prompt gamma activation analysis

In ancient China during the Shang dynasty, ca. 1600 BCE–1046 BCE, intricate jade and bronze dagger-axes (ge) were made and used by the elite as ritual symbols of power and prestige. These meticulously crafted ceremonial weapons consist of a nephrite jade [Ca2(Mg, Fe)5Si8O22(OH)2] blade mounted in a bronze haft. Several examples of these dagger-axes are included in collections in the United States. There has been recent interest in applying neutron radiography to image the jade tang hidden within the bronze haft and uncover early manufacturing techniques. As a preliminary test of feasibility, a simulated dagger was made using a modern replica blade carved from nephrite from Wyoming, USA, and copper alloy plates. The simulated dagger was first imaged by X-ray and neutron radiography at the NIST Neutron Imaging Facility. The details of the jade tang within the copper alloy haft were clearly visible. Subsequently, the nephrite blade and the copper alloy plates were analyzed by cold prompt gamma neutron activation (PGAA) to evaluate the feasibility of this technique for identifying the nephrite source. The PGAA was performed at the Cold Neutron PGAA station at NIST. Three nephrite specimens in the Smithsonian collection from China, Siberia and Taiwan, characterized previously by electron microprobe analysis, were used as comparative standards. The major nephrite elements - Ca, Mg, Fe and Si - were analyzed with uncertainties in the range of 0.3%–0.4%. Three of the trace elements conventionally used for sourcing, Cr, Mn and Ni, were analyzed with similar uncertainties. The residual radioactivity of the objects was below the NRC exempt limits.

The study of material flow behaviour in dissimilar material FSW of AA6061 and Cu-B370 alloys plates

Friction stir welding is a solid-state joining process which proved to be very effective for similar low strength materials. However, the joining of dissimilar materials is far complex than the similar materials because of divergent material properties. The need to study friction stir welding of dissimilar materials is inevitable due to increasing demand of modern industries. In the current study, the joining of aluminium alloy (AA-6061) and copper alloy (Cu-B370) plates is accomplished for studying the material flow movement throughout welding zone. A novel material flow model for dissimilar material friction stir welding is proposed based on the temperature and strain rate dependent material properties. The model used the volume of fluid (VOF) approach in the commercial FVM package ANSYS fluent 14.5. Experiments are also conducted to validate the model with thermal profiles and optical micrographs. Furthermore, the effect of tool rotational and the welding speed are studied on the material movement. It is found that process parameter had a huge impact on the nugget zone formation during the welding. The tool rotaion and welding speed directly affect the amount of platisized material mixing.

Creep-fatigue life prediction of perforated copper-alloy plate by using Digital Image Correlation Method

Creep-fatigue life prediction of perforated copper-alloy plate by using Digital Image Correlation Method

Effects of different wire chemical compositions on the mechanical and microstructural characteristics of copper brazing joints

Abstract In this study, commercially pure (99.5 wt.-%) copper alloy plates were brazed using an oxy-gas flame with four different brazing alloys in butt and lap joints, and the brazing capability, the microstructural and mechanical property changes were examined. The experimental results showed that L-CuZn39Sn brazing wire used in the butt joining caused porosity and an adverse effect on the microstructural and mechanical properties. However, in lap joining, it was observed that the mechanical properties of this material show identical characteristics compared to other brazing wires. In lap joining conducted using the L-CuNi10Zn42 alloyed brazing wires, a very good grain structure originated by diffusion was observed.

Effect of explosive mixture on quality of explosive welds of copper to aluminium

The aim of this research is to investigate the influence of explosive ratio and type of sensitizer on the quality of explosive welds between copper and aluminium alloy plates. The welds were performed on a partially overlapping joint configuration using an emulsion explosive (EE) with two different sensitizers, hollow glass microspheres (HGMS) and expanded polystyrene spheres (EPS). Welds with an improved surface were achieved by using the HGMS sensitizer. A higher wave amplitude was registered in welds produced with the EPS sensitizer. In turn, the dimension of the molten pockets was influenced by the explosive ratio, increasing in size with increases in the values of this parameter. The intermetallic content of these zones varied according to the sensitizer type. Unlike the CuAl2 phase, the Cu-richer phases CuAl and Cu9Al4 were only identified in welds performed using the EPS sensitizer. An increase in hardness was observed at the interface of all welds, which resulted from both the presence of intermetallic phases and the plastic deformation of the materials promoted by the impact. This effect was most evident on the aluminium alloy side. All the welds had a greater strength than copper, i.e. the weakest material of the joint.

Effects of filler wire on residual stress in electron beam welded QCr0.8 copper alloy to 304 stainless steel joints

Abstract The electron beam welding (EBW) of 304 stainless steel to QCr0.8 copper alloy with or without copper filler wire was studied in detail. The temperature fields and magnitude and distribution of stress fields in the joints during the welding process were numerically simulated using finite element method. The temperature cycles and residual stresses were also experimentally measured by thermometric and hole-drilling methods, respectively. The accuracy of the modeling procedure was verified by the good agreement between the calculated results and experimental data. The temperature distribution in the joint was found to be asymmetric along the center of weld. In particular, the temperature in the copper alloy plate is much higher than that in the 304 SS plate owing to the great difference in thermal conductivity between the two materials. The peak three-dimensional residual stresses all appeared at the interface between the copper and steel in the two different joints. Furthermore, the weld was subjected to tensile stress. The longitudinal residual stress, generally the most harmful to the integrity of the structure among the stress components in EBW with filler wire (EBFW), was 53 MPa lower than that of autogenous EBW (AEBW), and the through-thickness residual stress was 12 MPa lower. The transverse residual stress of EBFW was 44 MPa higher than that of AEBW. However, analysis of the von Mises stress showed that the EBFW process effectively reduced the extent of the high residual stress region in the weld location and the magnitude of the residual stresses in the copper side compared with those of the AEBW joint.

電磁圧接回路におけるインダクタンスの影響

Magnetic pulse welding is effective for lap-joining similar and dissimilar sheet metals such as Al/Al, Cu/Cu, and Al/Cu. A discharge circuit is used for the seam welding. It is composed of a flat one-turn coil and an energy-storing capacitor bank. The coil is an important component to obtain a high-density magnetic flux, and is made of one copper alloy plate, instead of a winding. The influence of the seam length of a sheet metal has been confirmed by welding an aluminum sheet to another aluminum sheet. It has been clarified that magnetic pulse welding is suitable for joining a sheet metal with increasing seam length, because the effective inductance increases with increasing seam length. As a result of investigating the transfer quantity of the electric energy from a capacitor to a coil, it has been found that magnetic pulse welding with a high energy efficiency can be used to join sheet metals if the transfer coefficient is large. On the basis of the experimental results, the influence of the remaining inductance on the transfer coefficient is calculated. A decrease in the remaining inductance adds to the welding capability of equipment and reduces the electric energy consumption.

Resistance to copper ions and antibiotics in marine heterotrophic bacteria in the coastal waters of Vietnam

Copper and antibiotic resistance was experimentally studied for the first time in marine het� erotrophic bacteria that were isolated from microfoulings of copper and copperalloy test plates in coastal waters of Vietnam. Resistance to copper ions and to at least one of the antibiotics tested was detected in 78.7% of the isolates. A total of 28 models of antibiotic resistance were found in the bacteria. All strains isolated from the foulings of the copper plates were resistant to seven or more antimicrobials. The microfouling communi� ties of copper and copperalloy plates were dominated by Bacillus spp. and Staphylococcus spp. Copper and antibiotic resistance was statistically independent of the taxon of the tested bacteria.

Preparation of W/Cu Functionally Graded Material

A W/Cu system functionally graded material (FGM), which may be used as plasma facing component for fusion reactors, was prepared by inserting W-Cu layers with gradient composition between tungsten and copper alloy plates. W-Cu gradient layers were hot-press sintered from W-Cu powder mixtures added with zinc powder as the sintering aid, whose relative density increased with sintering temperature, reaching a value higher than 96% at 850°C. XRD and SEM measurements showed that the sintered W-Cu gradient layers were the mechanical mixtures of W and Cu. A wholly dense W/Cu system FGM was then obtained at 850°C by hot-press, whose composition and structure changed gradually. The finite element method (FEM) calculation showed that the residual stresses in the W/Cu FGM were effectively reduced as compared with the directly-bonded W/Cu joint.

Confined growth of thin mordenite films into microreactor channels

Abstract This communication presents the production of a mordenite film growth totally confined into 350 μm wide microchannels on copper alloy plates for microreactor preparation. The growth is obtained in open channel configuration by secondary synthesis after 12 h of treatment over this highly thermal conductivity support. The confined growth presents a high overall quality. It is crystalline, uniform, and adherent; it totally covers the microchannels surface and has 5 μm. These properties are confirmed by XRD, SEM and EPMA characterizations.

Evaluation of pure tin plated copper alloy substrates for tin whiskers

PurposeThe purpose of this paper is to present the results from work on a project aimed at evaluating six different copper alloy substrates coated with pure tin for tin whisker growth. The influence of intermetallic growth between the copper alloy substrate and the tin‐plating on the growth of tin whiskers has been investigated.Design/methodology/approachThe experiment consisted of six substrates of different alloys of copper, plated with bright tin including copper beryllium, cartridge brass, phosphor bronze, Cu‐Ni‐Si “7025” and Cu‐Ni‐Sn “spinodal”. The samples were mechanically stressed and then subjected to temperature humidity storage conditions for 1,000 h. These samples were then evaluated for tin whisker growth and intermetallic layer thickness.FindingsOf the six samples five showed tin whisker growth. For these samples the intermetallic layer thickness has little effect on tin whisker growth. Sample with Cu‐Ni‐Sn “spinodal” alloy substrate showed very low whisker density and comparatively lower maximum whisker length than the other tested substrate material.Research limitations/implicationsMore samples per condition should be evaluated to bolster the conclusions. For the sample without tin whisker growth, holes on the surface of the plating were observed. The holes in the plating provide an opportunity for stress relaxation after the plating process. Since stress in the plating layer is low, tin whiskers are not formed on the sample surface.Originality/valueThe paper details the tin whisker growth on six tin plated copper substrate samples. The intermetallic layer thickness for each copper alloy substrate is calculated. The relationship between the intermetallic layer thickness and tin whisker growth for the six substrates are discussed.

電磁シーム圧接に及ぼすコイル形状の影響

A coil used in this seam welding has a large mechanical strength because it is fabricated from one copper alloy plate. When the coil has a small width and a small thickness, the welding of sheet metals can be performed using a low discharge energy in general. However, the coil is unfit for an experiment with a high discharge energy because the mechanical strength of the coil decreases with a decrease in coil cross-sectional area. Therefore, the proper selection of coil shapes is important, and the coil shape should be determined for the size of the sheet metals. The influence of coil width on welding an aluminum sheet to an aluminum sheet or a magnesium alloy sheet is confirmed. It becomes clear that a coil of 3 mm width is used only for the experiment with a low discharge energy because of its low durability and the influence of discharge circuit. To improve energy efficiency, the coil with enough cross-sectional area and many grooves of uniform depth is fabricated, and the effect is confirmed. A coil with grooves can weld sheet metals with a lower discharge energy compared with a coil without grooves.

The interfacial structure of plated copper alloy resistance spot welded joint

Plated copper alloys are widely used in electron industry. The plating lay caused the farther decreasing of the welding property of copper alloys, whose intrinsic weldability was poor. In this paper, the bronze and brass specimens with nickel–tin double plating layer were joined by resistance spot welding method. The microstructure and peel strength of the joints were investigated. The experiment results show that a sandwich-like structure was obtained in the faying surface after welding, and the nickel plating layer thickness had severe effect on the reliability of the joints.

An Application of a Thin Film Preparation Apparatus with a Broad Ar Ion Beam (Ion Slicer) to Corrosion of a Gold Plated Copper Alloy

An Application of a Thin Film Preparation Apparatus with a Broad Ar Ion Beam (Ion Slicer) to Corrosion of a Gold Plated Copper Alloy

Fretting corrosion of lubricated tin plated copper alloy contacts: Effect of temperature

The fretting corrosion behaviour of lubricated tin plated copper alloy contacts at ambient and elevated temperatures is addressed in this paper. At 27 °C, lubrication is very effective and the contact resistance remains stable for several thousand fretting cycles whereas at elevated temperatures (155 °C) the performance of lubricated contact is not appreciable. Surface profile and surface roughness confirm that the lubricated contacts have a smoother profile and experience a lesser damage at the contact zone at ambient as well as at elevated temperatures. The mechanism of fretting corrosion of tin plated contacts appears to be similar with and without lubrication at all the temperatures studied. The difference in performance of the lubricated contacts at ambient and elevated temperatures is due to the faster wear rate of tin coating at elevated temperatures. Oxidation of the contact zone of the lubricated contacts is prevented at all temperatures studied. The study concludes that lubrication is effective in improving the life of the tin plated copper alloy contacts under fretting conditions at ambient temperatures whereas at elevated temperatures lubrication provides only a marginal improvement in performance. The decrease in performance of lubricated tin plated contacts at elevated temperatures is due to the higher wear rate of tin coating and not due to evaporation of the lubricant.