Effect Of Copper Content Research Articles

Effects of copper content on microstructure and mechanical properties of open-cell steel foams

The effects of copper content on the microstructural and mechanical properties of steel foams are investigated. Spherical urea granules, used as a water-leachable space holder, were coated with a mixture of iron, ultrafine carbon, and different amounts of copper powders. After the mixture was compacted and the space holder was removed by leaching, a sintering process was performed under an atmosphere of thermally dissociated ammonia. Microstructural evaluations of the cell walls were carried out using optical microscopy and scanning electron microscopy in conjunction with energy-dispersive X-ray spectroscopy. In addition, compression tests were conducted to investigate the mechanical properties of the manufactured steel foams. The results showed that the total porosity decreases from 77.2% to 71.9% with increasing copper content in the steel foams. In the foams’ microstructure, copper islands are mostly distributed in pearlite and intergranular carbide phases are formed in the grain boundaries. When the copper content was increased from 0 to 4wt%, the elastic modulus, plateau stress, fracture stress, and fracture strain of manufactured steel foams improved 4.5, 6, 6.4, and 2.5 times, respectively.

Effect of copper content on the properties of graphite-copper composites formed using the plasma spray process

Graphite‑copper composite coatings are often used for the production of electrical machines because they are characterized by stable electrical and mechanical properties. The plasma spraying method was used to form such coatings in this work, as we aimed to evaluate the influence of copper content in the initial powders on the properties of graphite‑copper composite coatings. The graphite‑copper coatings were deposited on stainless steel and quartz glass substrates, as the copper content of the initial powder ranged from 2 to 60%. As shown by SEM studies, at small amounts of copper (up to 10%) in the initial powder the micro-derivatives of the spherical form are formed on the coatings. Meanwhile, XRD analysis have shown that mechanical stresses due to different thermal expansion coefficients between the coating and the substrate are characteristic for graphite‑copper coatings. The measurements of electrical conductivity shown that the maximum electrical conductivity (of 10 S) is obtained when the copper content in the initial powder reaches 20%. Despite the increase of the copper content in the initial powder above 20% the electrical conductivity of the coatings remain constant. The microhardness studies have shown that with the increase of copper content in initial powder from 2 to 60%, the microhardness of graphite‑copper composite coatings is reduced by about 2 times, while the plasticity increase from 11 to 19% is observed.

Effects of copper content on microstructure and mechanical properties of powder-forged rod Fe-C-Cu alloys manufactured at elevated temperature

The microstructure and mechanical properties of powder-forged Fe-C-Cu alloys manufactured at an elevated temperature were evaluated. It was found that the mechanical properties of the alloys were no worse than those in the literature, and the contribution of copper to the strength was quantified: the major strengthening mechanism of copper is grain-refinement strengthening rather than precipitation strengthening. Then, to ensure the safety of the elevated-temperature manufacturing, the hot-deformation behaviour of the Fe-C-2.5Cu alloy was investigated via construction of the constitutive equation and the hot-processing map, which proved that the high-temperature manufacturing was not only safe but also efficient. Finally, fatigue tests were conducted on the powder-forged connecting rods and 5154 wrought steel connecting rods for the same engine application, and the results showed that the powder-forged connecting rods had better fatigue strength and higher reliability.

Metabolic profiling of copper-laden hepatolenticular degeneration model rats and the interventional effects of Gandou decoction using UPLC-Q-TOF/MS

The direct cause of hepatolenticular degeneration (HLD) is copper metabolic disorder caused by autosomal recessive inheritance. Gandou decoction (GDD), a classical traditional Chinese medicine formula, exhibits unambiguous therapeutic effect on HLD in China for decades. However, the mechanism of effect on HLD is not clear. With this purpose, the effects of copper content and histopathology inspection on the HLD rat model were investigated. Then, metabolomics study based on ultra-performance liquid chromatography quadrupole-time-of-flight mass spectrometry (UPLC-Q-TOF/MSE) analysis and multivariate statistical analysis was adopted to further reveal the mechanism of action of GDD against HLD. The results showed that the characteristics of liver tissues after GDD treatment were significantly reversed, close to the control group, suggesting that GDD has a therapeutic effect on HLD. Furthermore, HLD interferes with 2 metabolites of the metabolic pathway in rats. Among them, up-regulation of Lactic acid, Tryptophan, Phenylalanine, Triacylglycerol and down-regulation of Linoleic acid, Alpha Linolenic acid, Phosphatidylcholine, Taurine is particularly significant. Analysis of metabolic pathways by a unique pathway analysis revealed significant changes in several pathways including lipid metabolism, amino metabolism and glucose metabolism in HLD. This study showed that GDD could provide satisfactory therapeutic effects on HLD and metabolomics study can be utilized to further understand the molecular mechanisms.

Statistical analysis of cutting forces and hole accuracy in reaming an Al–Si–Mg alloy (6351) with different copper contents

The main purpose of this work is to study the influence of copper content on Al–Si–Mg aluminum alloy’s (6351) machinability. This alloy’s machinability was evaluated through cutting tool torque and thrust force measurements, holes’ surface roughness, diameter, roundness, cylindricity and subsurface modifications during the reaming process. The Al–Si–Mg alloy samples were produced with five levels of copper (0.07%, 0.23%, 0.94%, 1.43% and 1.93%) and have a chemical composition of the other alloying elements practically constant within the recommended range by the Aluminum Association for this alloy. The main mechanical properties of the 6351 aluminum alloy samples were obtained by microstructural analysis and microhardness, hardness and tensile tests. Major amounts of copper resulted in a significant increase in microhardness, hardness and ultimate tensile strength of the aluminum alloy, while elongation after fracture decreased. A 23 factorial design was used to verify the effect of copper content and cutting parameters cutting speed and feed rate in machinability responses. Furthermore, it was developed an adjusted model to optimize the cutting parameters selection to machine the alloy with the best copper content for each response parameter of the reaming process. The results showed a significant influence of copper content in this aluminum alloy’s machinability. Lower values of torque and thrust forces, better surface finish, lower roundness and cylindricity deviation were obtained increasing copper content in Al–Si–Mg aluminum alloy (6351).

Effect of Copper on the Microstructure and Properties of Phosphorus Cast Iron for the Anode of Aluminum Electrolyzer

The effect of copper content on the microstructure and properties of Phosphorus Cast Iron for the anode of aluminum electrolyzer is studied in this paper. After adding 0.41–1.52 wt.% Cu in Phosphorus Cast Iron and heated at 800 °C for 24 h, the matrix microstructure of samples is ferrite, and the graphite and phosphorus eutectic are refined. The impact toughness increases from 0.69 to 0.81 J/cm2. The bulky sheet graphite can increase scattering probability of electron which will increase the electrical resistivity of cast iron. The resistivity of samples with 0.41–1.52 wt.% Cu (9.21 × 10−7–9.77 × 10−7 Ω m) is evidently lower than that of sample without Cu (1.12 × 10−6 Ω m). The resistivity increases initially and then decreases with increasing Cu content. The average thermal expansion coefficients between 20 and 800 °C of samples with 0.41–1.52 wt.% Cu are changed in 14.03 × 10−6–15.15 × 10−6 K−1 [slightly larger than that of sample without Cu (13.72 × 10−6 K−1)]. The high temperature oxidation resistance and corrosion resistance are also improved with the addition of Cu.

Effects of Copper Content and Mold Temperature on the Hot Tearing Susceptibility of Mg-7Zn-xCu-0.6Zr Alloys

The effects of copper (Cu) content and mold temperature on the hot tearing susceptibility (HTS) of Mg-7Zn-xCu-0.6Zr (x = 0, 1, 2) alloys were investigated experimentally using a T-type hot tearing mold. The crack volumes were measured by paraffin permeation method, and the solidification process was analyzed by thermal analysis and by using the Clyne and Davies model. The microstructure and morphology of the crack zone of Mg-7Zn-xCu-0.6Zr alloys were characterized by scanning electron microscopy, and the composition of alloys was analyzed by X-ray diffraction. The results showed the formation of a new phase of MgZnCu in the alloys with Cu addition. Moreover, addition of Cu also led to the refinement of microstructures of Mg-7Zn-xCu-0.6Zr alloys. The HTS of Mg-7Zn-xCu-0.6Zr alloys decreased with the increase in both the content of Cu and the mold temperature.

Effect of copper content on the dynamic compressive properties of fine-grained tungsten copper alloys

Experiments were conducted to evaluate the effect of Cu contents on the microstructures and dynamic compressive properties of three kinds of fine-grained tungsten copper (W-Cu) alloys with Cu contents in the range of 20–40 wt% prepared by isostatic cold pressing and infiltration. With the Cu content decreases from 40% to 20%, W grains grow slightly together with the W-W contiguity increasing and the homogeneity of microstructure improving. The dynamic yield strengths show an obvious increased tendency from 320 MPa in 60W-40Cu alloy to 1100 MPa in 80W-20Cu alloy. The yield strengths of the alloys show obvious strain rate strengthening effect. The three fine-grained W-Cu alloys exhibit good plasticity under compression with the dynamic critical failure strains of 0.6–0.85. The fracture mechanism is dependent on Cu content. The main failure modes are tearing of Cu phase, separation of W-W boundaries along with tearing of Cu phase, and failure of W shearing bands in 60W-40Cu, 70W-30Cu and 80W-20Cu alloys, respectively.

Effect of Copper Content on the Structure and Phase Transformations in Melt-Spun TiNi–TiCu Alloys

Thin ribbons 30–50 μm thick of the Ti50Ni50–xCu x (x = 25, 26, 28, 30, 32, 34; 36, 38 at %) alloys are produced by the melt-spinning technique at a cooling rate of approximately 106 K/s. It is revealed that at the content of copper 25 and 26 at % the alloys are in the amorphous-crystalline state, while at the content of copper above 26 at % the alloys are in the amorphous state. It is shown that isothermal crystallization of alloys with the copper content from 25 to 32 at % leads to formation of single-phase B2 structure, which upon cooling transforms into the martensite phase B19. A noticeable decrease in characteristic temperatures of martensitic transformation at the increase in content of copper is revealed. In the alloys with the content of copper more than 32 аt % after crystallization, the two-phase structure of B2 + B11 is formed; at the same time, the B11 phase (TiCu) substantially prevents B19 ↔ B2 transformation in the alloy with 34 at % copper and blocks all structural transformations in the alloys with 36 and 38 at % copper.

Effect of copper content on the corrosion behaviors and antibacterial properties of binary Mg–Cu alloys

Biodegradable Mg–Cu alloys have attracted many researchers attention due to their characteristics of osteogenesis, angiogenesis, and long-lasting antibacterial effects. In this paper, the effect of copper content on the corrosion behaviors and antibacterial properties of binary Mg–Cu alloys was studied. Microstructure characterization, immersion test, electrochemical test and antibacterial test were carried out. The results show that with the increase of Cu content, the corrosion rate of Mg–Cu alloys was increased greatly due to the galvanic corrosion between Mg matrix and Mg2Cu intermetallic phase. The corrosion rate of Mg–0·3Cu alloy was almost 10 times as fast as Mg–0·1Cu alloy in 0·9 wt-% NaCl solution. Antibacterial test showed that Mg–Cu alloys could efficiently reduce the viability of Candida albicans with the addition of Cu above 0·1 wt-%. Mg–0·1Cu has good potential to be used as antibacterial implants due to its good corrosion resistance and antibacterial property.

Quench sensitivity of novel Al–Zn–Mg–Cu alloys containing different Cu contents

The effect of copper content on quench sensitivity in novel Al–Zn–Mg–Cu alloys containing high zinc content was investigated by Jominy end quench test. Electrical conductivity and hardness test, temperature collecting, and transmission electron microscopy (TEM) technique were adopted for the properties and microstructure characterization of three alloys with different copper contents. The results indicate that the electrical conductivity of all three alloys increases with the increase of distance from the quenched end, while the hardness shows an opposite trend. If the dropping of 10% hardness is defined as the critical evaluation standard of quenching, the depth of quenched layer of Alloys I, II, and III are 70, 55, and 40 mm, respectively. The precipitation behavior on grain boundaries of three alloys is similar except for a little difference in size, while the size of precipitates in grains of Alloy III with higher copper content is larger than those of the other two alloys at the same location. Considering all results, the stability of the supersaturated solid solution of Alloy III is lower than those of the other two alloys, meaning that Alloy III shows the highest quench sensitivity. Higher copper content leads to higher quench sensitivity in novel Al–Zn–Mg–Cu alloys with the same content of magnesium, zinc, and other trace elements.

Investigation of sintered properties on infiltrated tungsten–copper composite along the infiltration direction

ABSTRACTTungsten–copper composites exhibit excellent resistance to erosion and good electrical as well as thermal conductivity. W–Cu composites are mainly used for heat sinks, electrical contacts and transpiration cooling applications. In this investigation the microstructure, mechanical and electrical properties of infiltrated tungsten–copper composite along the infiltration direction have been studied. The microstructures of the top, middle and bottom regions of the composite were evaluated using both optical and scanning electron microscope. Bulk hardness, electrical conductivity, instrumented hardness and contiguity were measured along the depth of W–Cu composite. It was found that the copper phase fraction decreases along the infiltration direction of the specimen. The effect of distribution of copper in the W–Cu system has a significant influence on the mechanical and the electrical properties. The effect of copper content on indentation depth, instrumented hardness, Young’s modulus, and stiffness of the composite has been evaluated using an instrumented hardness tester.

Effect of copper on the up-regulation/down-regulation of genes, cytotoxicity and ion dissolution for mesoporous bioactive glasses

In the present study, copper-based (25 − x)CaO − xCuO −10P2O5 − 5B2O3 − 60SiO2 (x = 2.5, 5, 7.5, 10 mol%) mesoporous bioactive glasses (MBGs) were synthesized using the sol–gel technique with cetyltrimethyl ammonium bromide as the structure-directing agent. The live–dead cell count and cytocompatibility of MBGs for J774A.1 murine macrophages have also been investigated for different concentrations of MBGs. The ionic dissolution profile for Ca, P and Si has been evaluated in the simulated body fluid. The effect of copper content as well as the ionic dissolution products on the up-regulation and down-regulation of TGIF-2, HDAC-4, Smurf-1, mir-30c and mir-130a genes for the murine model are investigated using reverse transcription-polymerase chain reaction. Silica and calcium release follows a similar trend as followed by gene up-regulation of TGIF-2, HDAC-4 and mir-30c genes. This indicates that silica and calcium release influence gene expression.

Copper Doped Phosphate Glass as an Optical Bandpass Filter

The phosphate glass system of chemical composition 45P2O5-45 ZnO-(10–x–y)Na2O-xCuO-yY2O3; where [x = 0, 2, 4, 6 and y = 0, 1 mol%] was prepared by the conventional glass melt quenching technique. The glassy nature of the prepared glasses was proven by x-ray diffraction. The effect of copper content on density ? and molar volume was investigated. It was found that the density of the glass increases by increasing the copper content, while the molar volume VM follows the opposite trend. Optical absorption spectra were measured in the range from 190 to 1100 nm and Two broad bands are observed in both UV and IR regions. Analyses of the obtained results were used for determination of the optical band gap energy (Eopt) Urbach energy and the cutoff in UV and IR regions. The observed behavior shows that the prepared glasses act as bandpass filters in the visible range. The intensity and width of the transmitted band depend on the copper content. Different physical properties such as refractive index and dielectric constant have been calculated. Eopt values of glass samples were estimated and found to decrease with increasing CuO content.

Bifunctionality of Cu/ZnO catalysts for alcohol-assisted low-temperature methanol synthesis from syngas: Effect of copper content

Alcohol-assisted low-temperature methanol synthesis was conducted over Cu/ZnO_X catalysts while varying the copper content (X). Unlike conventional methanol synthesis, ethanol acted as both solvent and reaction intermediate in this reaction, creating a different reaction pathway. The formation of crystalline phases and characteristic morphology of the co-precipitated precursors during the co-precipitation step were important factors in obtaining an efficient Cu/ZnO catalyst with a high dispersion of metallic copper, which is one of the main active sites for methanol synthesis. The acidic properties of the Cu/ZnO catalyst were also revealed as important factors, since alcohol esterification is considered the rate-limiting step in alcohol-assisted low-temperature methanol synthesis. As a consequence, bifunctionality of the Cu/ZnO catalyst such as metallic copper and acidic properties was required for this reaction. In this respect, the copper content (X) strongly affected the catalytic activity of the Cu/ZnO_X catalysts, and accordingly, the Cu/ZnO_0.5 catalyst with a high copper dispersion and sufficient acid sites exhibited the best catalytic performance in this reaction.

Effects of copper content on properties of CZTS thin films grown on flexible substrate

In this work, Cu2ZnSnS4 (CZTS) thin films on the flexible molybdenum foils were fabricated by vacuum-based magnetron sputtering and followed by annealing in the sulfur vapor. The effects of copper content on CZTS films’ structures and properties were studied using X-ray diffraction (XRD), Raman scattering, energy dispersive spectroscopy (EDS), scanning electron microscopy (SEM), and UV–Vis spectroscopy techniques. According to the experimental results, the strong peak in XRD pattern along (112) plane confirms the kesterite crystal structure of CZTS thin films. A suitable increase of the copper content can improve the crystallinity of the CZTS thin films. However, the continued increase in copper content can lead to the presence of Cu2S and Cu3SnS4 phases in sulfurized CZTS thin films. Furthermore, the performances of flexible CZTS thin films after repeated bending were also explored. In our case, no cracks were observed by SEM, but a fold appeared in the surface. Also, increasing copper content makes the fold less obvious.

Effect of copper content on microstructure and mechanical properties of Al/Sip composites consolidated by liquid phase hot pressing

Aluminum (Al)-based composites reinforced with 50wt.% silicon (Si) were prepared by liquid phase hot pressing. Elemental copper (Cu) powder was mechanically mixed with gas-atomized AlSi alloy powder to form partial liquid phase during sintering, and its effect on densification, microstructure and mechanical properties was investigated. The results indicate that the amount of precipitated Al2Cu (θ) phase increases gradually as the Cu content increases from 0 to 2wt.%. Accordingly, it promotes solid solution hardening along with precipitation hardening, and leading to an enhancement of mechanical properties. However, the presence of too much brittle Al2Cu phase and large Si phase caused by SiSi clustering in the Al-4wt.%Cu/Sip composite debase the mechanical properties remarkably. Cu addition reduces the melting point and results in the formation of Al2Cu phase, thus reducing the consolidation temperature and enhancing the strength of Al matrix. Therefore, the addition of minor elemental Cu powder is an effective approach to promote the preparation and the performance of Al/Sip composites by powder metallurgy.

Effect of copper content on the properties metallopolymers based on phenylone

Effect of copper content on the properties metallopolymers based on phenylone

Effects of Copper Content and Ni Activator on the Densification of W-Cu Composite via Infiltration Process

Effects of Copper Content and Ni Activator on the Densification of W-Cu Composite via Infiltration Process

Effects of copper content on the shell characteristics of hollow steel spheres manufactured using an advanced powder metallurgy technique

Metallic hollow spheres are used as base materials in the manufacture of hollow sphere structures and metallic foams. In this study, steel hollow spheres were successfully manufactured using an advanced powder metallurgy technique. The spheres’ shells were characterized by optical microscopy in conjunction with microstructural image analysis software, scanning electron microscopy (SEM), energy- dispersive X-ray spectroscopy (EDX), and X-ray diffraction (XRD). The microscopic evaluations revealed that the shells consist of sintered iron powder, sintered copper powder, sodium silicate, and porosity regions. In addition, the effects of copper content on various parameters such as shell defects, microcracks, thickness, and porosities were investigated. The results indicated that increasing the copper content results in decreases in the surface fraction of shell porosities and the number of microcracks and an increase in shell thickness.