Effect Of Cu Addition Research Articles

Effects of Cu addition on plasticity of Fe-6.5Si (wt.%) alloy at temperatures below 550 °C

The plasticity of Fe-6.5Si (wt.%) alloys with additions of 0, 0.3, 0.5 and 0.7 wt% Cu was investigated by tensile tests at intermediate temperatures below 550 °C. It was found that the plasticity of Fe-6.5Si (wt.%) alloy increased with Cu addition to up to 0.3 wt%, but decreased with further increase in Cu addition. When the Cu addition was increased to 0.7 wt%, the plasticity of the alloy became lower than that for the alloy without Cu addition. The reduction of cross-sectional thickness of the tested specimens confirmed that the onset temperatures of brittle to ductile transition were about 90, 262, 304 and 400 °C for Fe-6.5Si (wt.%) alloys with Cu additions of 0.3, 0.5, 0 and 0.7 (wt.%), respectively. Microstructure analysis suggested that the solubility of Cu in the alloy was or higher than 0.3 wt%, but lower than 0.5 wt%. The Cu dissolution in the solid solution increased the plasticity of the Fe-6.5Si (wt.%) alloy as a result of the reduced degree of long-range order. Increasing Cu addition beyond the solid solution limit caused the Cu-rich phase precipitation at grain boundaries, which embrittled the grain boundaries and hence severely reduced the plasticity of the alloy.

Effects of Cu addition on formability and surface delamination phenomenon in high-strength high-Mn steels

The formability of austenitic high-Mn steels is a critical issue in automotive applications under non-uniformly-deformed environments caused by dynamic strain aging. Among austenite stabilizing alloying elements in those steels, Cu has been known as an effective element to enhance tensile properties via controlling the stacking fault energy and stability of austenite. The effects of Cu addition on formability, however, have not been sufficiently reported yet. In this study, the Cu addition effects on formability and surface characteristics in the austenitic high-Mn TRIP steels were analyzed in consideration of inhomogeneous microstructures containing the segregation of Mn and Cu. To reveal determining factors, various mechanical parameters such as total elongation, post elongation, strain hardening rate, normal anisotropy, and planar anisotropy were correlated to the hole-expansion and cup-drawing test results. With respect to microstructural parameters, roles of (Mn,Cu)-segregation bands and resultant Cu-rich FCC precipitates on the formability and surface delamination were also discussed.

Fractal and Conventional Analysis of Cu Content Effect on the Microstructure of Al-Si-Cu-Mg Alloys

This work analyzes the effect of Cu additions on the microstructure of quaternary alloys Al-6Si-7Mg-xCu (x= 3, 5 and 7 wt.%) produced by conventional metallurgy. Microstructural modifications were studied using Optical Microscopy (OM), X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM), focusing on second phases identification and quantification. Conventional image analyses were developed measuring the total percentage of second phases, and individually for each phase determining its equivalent diameter, shape factor, roundness and aspect ratio; while fractal analyses were carried out complementarily through fractal dimension measurements for the whole microstructure and for individual phases. Compression tests were also carried out. SEM and XRD results revealed that second phases were eutectic Si, Mg2Si, Al2Cu and Al5Cu2Mg8Si6 (Q). The increase in Cu content led to higher quantities of these phases, mainly Al2Cu, which was barely present for the alloy with the lowest Cu content. Morphologies of second phases depended on Cu content, being present as eutectic, block like, finely dispersed or primary particles. The combination of conventional and fractal parameters provided a useful tool for comparatively analyze microstructural modifications and second phases features. It was also found that the compressive behavior of the alloys depended on the resulting microstructures.

Effect of Cu Addition on Microstructure, Mechanical Property and Texture Evolution of Extrusion-shearing ZK60 Mg-alloy

Effect of Cu Addition on Microstructure, Mechanical Property and Texture Evolution of Extrusion-shearing ZK60 Mg-alloy

The effect of Cu addition on the crystallization behavior and tribological properties of reactive plasma sprayed TiCN–Cu coatings

TiCN–Cu coatings were fabricated by reactive plasma spraying using Ti-graphite aggregates and Cu powders. The crystallization, mechanical and tribological properties were investigated. The results showed that TiCN–Cu coatings shared a face-center cubic structure and they consisted of TiC0·7N0.3, TiN0·3O, Cu2O, Cu, amorphous CNx and residual graphite phases. The addition of Cu mainly changed the crystallization behavior of the coating surface and binding surface with the substrate. Compared with TiCN coating, TiCN–Cu coatings had the lower hardness and hardness distribution uniformity. The incorporation of Cu improved the coating fracture toughness, while failed to improve the coating tribological properties. The main wear mechanism of TiCN–Cu coatings in the present sliding test were adhesive wear, coupling with partial tribo-oxidation wear.

Effect of Cu addition on porous NiTi SMAs produced by self-propagating high-temperature synthesis

AbstractThe focus of the study is on the effect of copper addition on the porosity, microstructure and mechanical properties of hot pressed NiTi and NiTiCu shape memory alloys (SMAs), ignited by means of self-propagating high-temperature synthesis (SHS). Optical microscopy, scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersive spectrometry (EDS), hardness tests and compression tests were applied respectively to determine the microstructure and mechanical behavior of the samples. The experimental results show that the addition of Cu into NiTi SMAs increases porosity and microhardness but also reduces compressive strength.

Understanding the Role of Copper Addition in Low-Temperature Toughness of Low-Carbon, High-Strength Steel

In this work, the effect of Cu addition on the microstructure and mechanical properties, in particular, low-temperature toughness, of low-carbon, high-strength steel was investigated. Steels with Cu concentrations varying from 1 to 2.5 wt pct in the place of carbon were prepared and then subjected to the two-step intercritical heat treatment. A mixed microstructure consisting of intercritical ferrite, tempered martensite, and retained austenite was obtained. There was an increased amount of retained austenite in the steels with Cu contents ranging from 0.23 to 2.5 wt pct. Therefore, Cu addition was beneficial for the stabilization of retained austenite. This phenomenon can be attributed to the enrichment of Cu in austenite and the increased driving force of reversed transformation caused by reduction in the T0 temperature (the temperature at which fcc austenite and bcc ferrite of identical composition have equal free energy). Furthermore, nanoscaled Cu precipitates were dispersed in the microstructure of Cu-containing steels. The combined effect of retained austenite and Cu precipitates could be the reason for excellent low-temperature toughness without loss in strength, which is featured by the impact energy of more than 120 J at 153 K (– 120 °C) for the Cu-containing steels. In addition to the deformation-induced transformation of retained austenite, bcc Cu precipitates act as misfit centers to improve the low-temperature toughness by enhancing the dislocation mobility and decreasing the ductile-to-brittle transformation temperature (DBTT).

Fe-TABANLI FeCoNiBSiNb İLE Co-TABANLI CoFeNiBSiNb CAMSI ŞERİTLERDE Cu İLAVESİNİN MANYETOKALORİK ÖLÇÜMLERE VE MANYETİK DİRENCE ETKİLERİ

In this research, the effects of Cu addition which ranges from 0 % to 1 % to Fe-based Fe 0.402 Co 0.201 Ni 0.067 B 0.227 Si 0.053 Nb 0.05 and Co-based Co 0.402 Fe 0.201 Ni 0.067 B 0.227 Si 0.053 Nb 0.05 glassy ribbons obtained by melt spinning method on magnetocaloric and magnetoresistance properties were investigated. In this regard, structural analyzes of the samples were evaluated by XRD, thermal properties were analyzed by DSC measurements, Curie temperatures were obtained from dM/dT vs temperature curves, magnetic properties were determined by using M-H and M-T measurements, magnetic entropy changes depending on temperature were used to determine magnetocaloric properties of the samples. In addition to these, the temperature dependent magnetoresistances were measured and the effects of adding Cu element to the composition on magnetoresistance properties were investigated. As a result, it has been concluded that the appropriate addition of Cu (about 0.75 %) on Fe- or Co-based metallic glasses enhances magnetocaloric properties and the proposed composition can probably be used for magnetic refrigeration at high temperatures.

The Antimicrobial Activity and Characterization of the Cast Titanium Copper Alloys with Variations of Copper Content

The effect of Cu addition on antimicrobial activity of Cast Ti-Cu Alloys against Staphylococcus aureus were studied. The Ti-Cu alloys were prepared with a variation of 0.5, 1, 2, 3, 4, 8 and 10 wt% of copper. Pure Ti metal was also prepared and tested as a comparison. The antibacterial was performed by killing activity test of colony forming unit (CFU) method with variation of contact time. Optical microscope observation, XRD, and the Vickers hardness test were carried out to characterize the investigated alloys. The results showed that Ti-Cu alloys were able to decrease the amount of bacteria by time. However, the activity of killing of bacteria in the varied range of Cu content did not show significantly different result. The highest bacterial kill ability in the alloy was observed in addition of 3 wt% Cu.

Effect of addition of Cu on the properties of eutectic Sn-Bi solder alloy

Abstract The present work reports the effect of Cu addition on the melting point, hardness and electrical resistivity of Sn-57 wt.% Bi eutectic solder alloy. Both binary eutectic Sn-57 wt.% Bi and ternary Sn-(57-x)Bi-xCu (x = 0.1, 0.3, 0.5, 0.7 and 1 wt.%) alloys containing various amounts of Cu were developed by melting casting route. The microstructure of the various solder alloys was analyzed using an optical microscope and a SEM. The variation in melting point, hardness and electrical resistivity of the Sn-Bi eutectic solder alloys with the addition of Cu was determined. The melting point of the eutectic Sn-Bi solder alloy was found to decrease up to the addition of 0.7 wt.% Cu. However, further addition of Cu led to an increase in the melting point of the alloy. Addition of Cu led to an increase in the hardness of the eutectic Sn-Bi solder alloy whereas the electrical resistivity of this alloy was found to increase up to the addition of 0.7 wt.% of Cu beyond which a decrease in the electrical resistivity was observed. A change in the microstructure of the solder alloy was observed when it was reheated above the melting temperature.

Effects of Cu addition to n-type β-FeSi2/Si composite on the Si precipitation and its thermoelectric properties

We investigated the influence of Cu addition to Co-doped β-FeSi2/Si thermoelectric material. We expected the addition of Cu to accelerate the eutectoid decomposition of α-Fe2Si5 phase resulting in a finer distribution of Si secondary phase. We added 1 mass% and 2 mass% of Cu followed by the annealing process in various conditions. We obtained a significant decrease of Si size, reaching less than 100 nm for composites with 2 mass% Cu, annealed at 650 °C-2 h. Within the same amount of Cu, Si size was clearly increased after annealed at 800 °C-4 h, suggesting that the phase transition is accelerated with the existence of Cu. The thermal conductivity value was greatly reduced for sample with 2 mass% Cu, compared with the experimental value of single β-FeSi2 and calculated value from the rule of mixture. This proves that the fine distribution of Si help suppress thermal conductivity despite the high value of the Si phase itself. However, the excessive amount of Cu (2 mass%) degenerated the electrical properties of β-FeSi2/Si. Nonetheless, the sample with 1 mass% Cu annealed at 800 °C for 4 h showed the highest ZT value of 0.1, indicating that it is essential to keep the balance of Cu amount and annealing conditions towards TE performance enhancement.

The Structural, Elastic and Electronic Properties of Ni3−xCuxSn4 (x = 0, 0.5, 1 and 1.5) Intermetallic Compounds via Ab Initio Calculations

With the ab initio calculations, the effects of Cu addition on the structural, elastic and electronic properties of intermetallic compound (IMC) Ni3Sn4 have been systematically investigated. The calculated formation heat indicates that Cu atoms preferentially occupy Ni 4i sites to form thermodynamically stable Ni3−xCuxSn4 (x = 0, 0.5, 1 and 1.5) compounds. Variation of lattice constants reveals the directional discrepancy of atomic bonding in (Ni,Cu)3Sn4 and the Zener anisotropy is refined by 13.4% after 21.4 at.% Cu addition. The polycrystalline elastic properties show a decreased tendency after Cu addition. However, the anisotropy of Young’s modulus and shear modulus in different crystal directions is effectively weakened in Cu doped IMCs. Both the density of states and electron density distribution indicate that Cu dopants will bond with Ni and Sn atoms, which influences the elastic amplitude and anisotropy of crystals.

Hot Deformation Behavior and Processing Map of a Cu-Bearing 2205 Duplex Stainless Steel

The hot deformation behavior and processing map of Cu-bearing 2205 duplex stainless steel (2205-Cu DSS) were investigated at temperatures of 950–1150 °C and strain rates of 0.01–10 s−1. The effects of Cu addition and different deformation parameters on deformation behavior were, respectively, characterized by analyzing flow curves, constitutive equations and microstructures. The results indicated that the shapes of flow curves strongly depended on the volume fraction of two phases. When deformed at low strain rate, DRV in ferrite was prompted with increase in the temperature and was further developed to continuous DRX. At high strain rate, flow localization preferentially occurred in ferrite at low deformation temperature due to the strain partitioning and relatively less fraction of ferrite. The activation energy for 2205-Cu DSS was 452 kJ/mol and was found to connect with the variation of strain, strain rate and deformation temperature. The optimum hot deformation parameters for 2205-Cu DSS were obtained in the temperature range of 1100–1150 °C and strain rate range of 0.1–1 s−1 with a peak power dissipation efficiency of 41%. Flow localization was the main way to lead to flow instability. Meanwhile, the Cu-rich precipitates were generated within a few ferrite grains when deformed at temperature lower than 1000 °C. The interaction between dislocations and Cu-rich precipitates at high strain rate, as well as the limited DRV in ferrite and DRX in austenite, contributed to the complex microstructure and flow behavior.

Effect of Cu addition to carbon-supported Ru catalysts on hydrogenation of alginic acid into sugar alcohols

The objective of this study was to investigate the effect of Cu addition to carbon supported Ru catalysts on the hydrogenation of macroalgae-derived alginic acid into sugar alcohols, mainly sorbitol and mannitol. Both geometric and electronic effects were determined based on results of H2-TPR, H2- or CO-chemisorption, and XPS analyses after Cu was added to Ru. The addition of Cu to Ru caused blocking of active Ru surface and electron transfer between Ru and Cu. The intimate interaction between Ru and Cu formed RuCu bimetallic clusters which expedited hydrogen spillover from Ru to Cu. The highest yield of target sugar alcohols of 47.4% was obtained when 5 wt% of Ru and 1 wt% of Cu supported on nitric acid-treated activated carbon reacted at 180 °C for 2 h. The RuCu bimetallic catalyst exhibited deactivation upon repeated reactions due to the carbon deposition on the catalyst.

Amorphous NiB alloy decorated by Cu as the anode catalyst for a direct borohydride fuel cell

In this study, amorphous NiB alloy decorated by Cu is prepared by chemical reduction. Moreover, the effect of Cu addition for the electrocatalytic activity of borohydride (BH4−) oxidation is studied. The physical characteristics of NiB or NiBCux nanoparticles are confirmed by transmission X-ray diffraction (XRD) and scanning electron microscopy (SEM). The physical characterization results demonstrate that the NiB or NiBCux nanoparticles have an amorphous structure and NiBCux nanoparticles have improved dispersity. The borohydride oxidation activity of the as-prepared catalysts is investigated by cyclic voltammetry (CV), linear scan voltammetry (LSV) and electrochemical impedance spectroscopy (EIS). Results indicate that the NiBCux/C nanoparticles have higher electrocatalytic activity for borohydride oxidation than NiB/C, and the borohydride oxidation current of NiBCux/C nanoparticles initially increases and then decreases with the increase in Cu content. The optimum molar content of copper in the six prepared catalysts is 2.2%. It is proposed that the addition of Cu is conducive to sodium borohydride adsorption, thereby improving the electro-oxidation activity for borohydride. Hence, amorphous NiB alloy decorated by Cu can enhance the electro-oxidation performance for borohydride.

The effect of copper addition on the corrosion resistance of cast duplex stainless steel

In this study, the effects of the addition of 3.01% Cu on the corrosion behaviour of cast duplex stainless steel aged for 1h at different temperatures between 450 and 600°C was investigated by electrochemical tests in 0.6M NaCl, 0.3M H2SO4 and 0.6M NaCl+0.3M H2SO4. A short ageing time increases the hardness and mechanical resistance of the Cu-containing steel by precipitation hardening. Potentiodynamic polarization and electrochemical impedance spectroscopy results show that the effect of Cu addition depends on the media studied. In addition, critical pitting temperature (CPT) measurements revealed that steel with 3.01% Cu has a lower pitting corrosion resistance. On the other hand, for both steels, the short time ageing caused a slight increase in CPT values.

Effect of Cu additions on mechanical properties of Ni3Sn4-based intermetallic compounds: First-principles calculations and nano-indentation measurements

The (Ni,Cu)3Sn4 phase as intermetallic compounds (IMCs) plays an important role in evaluating reliability of solder joints. The first-principles calculations were performed to investigate the phase stability, mechanical properties and electronic structures of Ni3Sn4 and Ni2.5Cu0.5Sn4 IMCs. The results shows that the doping of Cu atom not only reduced the phase stability but also weakened the mechanical properties of Ni3Sn4 crystal structure. Meanwhile, all studied Ni3Sn4-based structures were structural stability. Moreover, the anisotropy of Ni2.5Cu0.5Sn4 (2a site) was strongest while that of Ni2.5Cu0.5Sn4 (4i site) was the weakest. Based on analysis of electronic structures, it indicated that the ionic bonding of NiCu in Ni2.5Cu0.5Sn4 structure was weaker than covalent bonding of nearest-neighbor Ni in Ni3Sn4, which led to an energy reduction with the formation of banding states. By means of nano-indentation measurements, the young's modulus and hardness were measured to be 135.3 ± 8.4 GPa and 5.0 ± 0.63 GPa for Ni3Sn4 while 126.3 ± 7.6 GPa and 4.7 ± 0.72 GPa for (Ni,Cu)3Sn4, respectively, which were close to the value of calculated results.

The effect of Cu addition on wear mechanisms and tribological properties of aluminium matrix composites reinforced with SiC

The article discusses the results of research on the effect of 4 wt.% Cu addition on the tribological properties of composites based on aluminium matrix reinforced with SiC particles. The research also included the analysis of the microstructure and the hardness. The composites were made of elementary powders in a rigid die on a single-action compaction press and then sintered under the nitrogen atmosphere. The silicon carbide content was: 2.5; 5; 7.5; 10 and 15 wt.%. The tests of tribological properties were carried out using a block-on-ring T05 tester under the technically dry friction conditions, and the counter-sample was made of 100 Cr6 steel. The research covered the determination of mass losses, coefficients of friction as well as friction coefficient changes as the function of process duration and material. The obtained results proved that the addition of 4 wt.% Cu helps to reduce the friction coefficient and for composites that contain above 7.5 wt.% SiC also improves their wear resistance. It was also demonstrated that both the addition of Cu as well as an increase of SiC content in the composites have a positive effect on friction by reducing the adhesive wear share in the friction process.

In Vitro Osteogenic, Angiogenic, and Inflammatory Effects of Copper in β-Tricalcium Phosphate

AbstractTricalcium phosphate (TCP) is a promising candidate in bone and dental tissue engineering applications. Though osteoconductive, its low osteoinductivity is a major concern. Trace elements addition at low concentrations are known for their impact on not only the osteoinductivity, but also physical and mechanical properties of TCP. Copper (Cu) is known for its role in vascularization and angiogenesis in biological systems. Here, we studied the effects of Cu addition on phase composition, porosity, microstructure and in vitro interaction with osteoblast (OB) cells. Our results showed that Cu stabilized the TCP structure, while no significant effect of microstructure and porosity was found. Cu at concentrations less than 1 wt.% did not have any cytotoxic effect while decreased proliferation of OBs were observed at 1 wt.% Cu doped TCP. Addition of Cu upregulated collagen type I and vascular endothelial growth factor expression in a dose dependent manner at early time-point. Furthermore, Cu reduced inflammatory gene expression by human osteoblasts. These findings show that addition of Cu to TCP may provide a therapeutic strategy that can be applied in bone tissue engineering applications.

Corrosion Resistance of Cu-Alloyed Precipitation Hardenable Duplex Stainless Steel ASTM A890 Grade 1B

Duplex stainless steels (DSS) are corrosion resistant alloys largely used in chemical and petrochemical industries. Some commercial DSS contain 0.5-1.0% copper addition to improve the corrosion resistance by reducing the corrosion rate in non-oxidizing environments. Higher copper addition (≥ 2%) can also hard by precipitation, especially when fine copper precipitates (e phase) are produced. In this work, a cast copper alloyed DSS type ASTM A890 grade 1B with 3.01%Cu was investigated. Different levels of hardness were produced by solution treatment and aging at 450, 500, 550 and 600 oC for periods of time up to 1 hour. The corrosion resistance of aged DSS was evaluated by electrochemical tests in three media: 0.6 mol/L NaCl, 0.3 mol/L H2SO4 and 0.6 mol/L NaCl + 0.3 mol/L H2SO4 solutions. The results indicate that the effect of Cu addition depends on the media studied. Polarization studies in 0.6 mol/L NaCl showed a small anodic current peak occurred at around 400 mV vs. Ag/AgCl, with a strong influence on the passive film stability. Additionally, chronoamperometric measurements at 400 mV vs. Ag/AgCl showed a high electrochemical activity for the samples in 0.6 mol/L NaCl.