Influence Of Copper Addition Research Articles

Influence of Copper Addition on Glass Forming Ability, Thermal Stability, Structure and Magnetic Properties of Fe-Co-Based BMGs

The aim of the paper was investigation of the effect of Cu addition on glass forming ability (GFA), thermal stability, structure and magnetic properties of Fe-Co-based bulk metallic glasses (BMGs). The raw materials used in this experiment for the production of BMGs were pure Fe, Co, Cu and industrial Fe-B, Fe-Si, Fe-Nb ferroalloy. Investigations were carried out on BMGs in rods shaped with square section with side of 1.5mm. The structure of the investigated BMGs in rod form is amorphous. The addition of small amounts of Cu is effective in changing GFA and magnetic properties. The melting temperature - Tm remained almost constant for both investigated alloy. Two alloy compositions are at or very close to the eutectics, what according to ref. [1] should guarantee the best metallic glass-forming alloys. The investigated alloys have good soft magnetic properties. The successful synthesis of the Fe36.00Co36.00B19.00Si5Nb4 and Fe35.75Co35.75B18.90Si5Nb4Cu0.6 alloys with high GFA and good soft magnetic properties by using starting industrial alloys are encouraging for the future industry applications.

Influence of copper additives on the viscosity and stratification of iron melt

Viscosimetric data are obtained for Fe-Cu melts in heating and subsequent cooling of samples with 0–10 wt % Cu. Above the liquidus in the resulting phase diagram, the boundaries of the region where microheterogeneities of colloidal scale exist in the melt are found.

Structural role of Cu in the soil active glasses

Glasses from the SiO2-P2O5-K2O-CaO-MgO-CuO system acting as slow release fertilizers were synthesized by the melt-quenching technique. Influence of copper addition on structure of the glasses was evaluated by XRD, SEM, FT-IR and Raman spectroscopy. Chemical activity of the glasses in 2 wt.% citric acid solutions was measured by ICP-AES method. It has been found that increasing content of phosphorous increased solubility of copper in the structure of the studied glasses which was the result of formation of P-O-Cu bonds.

Influence of Copper Additions in Fe-10Ni (mass %) Alloys on Cooling Microstructures

Austenite/ferrite phase transformations in Fe-xCu-10Ni alloys, 0<x<15 (mass%), are studied under two different cooling conditions, ice-brined quenching or slow cooling in the dilatometer. The influence of copper addition and cooling rate on the microstructure of the alloys is studied. Metallographic examinations of quenched samples show that metastable transformations occur during cooling. As for Fe-Ni alloys, it is impossible to stabilize the high temperature phase (γFeNi) in the Fe-Ni-Cu alloys. Dilatometry measurements of the γ → α transformation temperature with a cooling rate of 2°C/min also indicate a metastable phase formation despite the low cooling rate. For all alloys, a mixture of massive and lath ferrite is observed, one being predominant depending on the cooling conditions and composition. It is shown that the cooling rate has nearly no influence on the microstructure of alloys with a small amount of Cu unlike the alloys containing more Cu. In all alloys containing Cu, nanometric γCu precipitates, much finer in the quenched samples, are detected in the ferrite grains.

Influence of Copper Addition and Temperature on the Kinetics of Austempering in Ductile Iron

Austempered ductile iron (ADI) is a material that exhibits excellent mechanical properties because of its special microstructure, combining ferrite and austenite supersaturated with carbon. Two ADI alloys, Fe-3.5 pct C-2.5 pct Si and Fe-3.6 pct C-2.7 pct Si-0.7 pct Cu, austempered for various times at 623 K (350 °C) and 673 K (400 °C) followed by water quenching, were investigated. The first ferrite needles nucleate mainly at the graphite/austenite interface. The austenite and ferrite weight fractions increase with the austempering time until stabilization is reached. The increase in the lattice parameter of the austenite during austempering corresponds to an increase of carbon content in the austenite. The increase in the ferrite weight fraction is associated with a decrease in microhardness. As the austempering temperature increases, the ferrite weight fraction decreases, the high carbon austenite weight fraction increases, but the carbon content in the latter decreases. Copper addition increases the high carbon austenite weight fraction. The results are discussed based on the phases composing the Fe-2Si-C system.

The influence of copper addition on microstructure and mechanical properties of thermomechanically processed microalloyed steels

The present study concerns the influence of Cu addition on the microstructural evolution and mechanical properties of directly air-cooled microalloyed thin-gauge steel. For this purpose, 1.5 wt% Cu was added to a Ti–B microalloyed steel. It is known that Ni addition to Cu-containing steel is beneficial to eliminate hot shortness caused by Cu. Therefore, the effect of Ni addition (half that of Cu in wt%) on the microstructure formation and mechanical properties has also been studied. Microstructures and mechanical properties of the directly air-cooled steels have demonstrated that addition of 1.5 wt% Cu along with 0.8 wt% Ni in Ti–B microalloyed steel results in a dual phase-like microstructure, which yielded attractive tensile strength (746 MPa) and ductility (31%). However, Cu addition deteriorated the impact toughness of the directly air-cooled Ti–B microalloyed steels.

Thermal stability and activation energy of some compositions of Ge–Te–Cu chalcogenide system

The present study investigates the influence of copper addition on the thermal stability, and the activation energy of the glass transition and crystallization for Ge26Te74− x Cu x (x = 2.5, 5, 7.5, 10 and 12.5 at%) glasses. Differential scanning calorimetric (DSC) results under non-isothermal conditions for the Ge–Te–Cu system are reported and discussed. From the heating rate (α) dependence of the glass transition temperature (T g) and the temperature corresponding to the maximum crystallization rate (T p), the activation energy for both glass transition and crystallization for the studied glasses were obtained. The glass-forming ability of the Ge26Te74− x Cu x glasses was evaluated using various thermal stability criteria based on characteristic temperatures. The K r(T) criterion has also been considered for the evaluation of glass stability from DSC data. The activation energy for crystallization decreases and thermal stability increases with increasing copper content.

Influence of copper addition on adhesive strength of Sn–3Ag–1·5Sb solder joints

The present work investigates the effects of adding a small amount of Cu to Sn–3Ag–1·5Sb solders. The present results indicate that adding 0·5 and 1·0 wt-%Cu to Sn–3Ag–1·5Sb solders causes the liquidus temperature to decrease from its original value of 233·4°C to 231·6°C and to 231·4°C, respectively. Furthermore, it is noted that the addition of 1·0 wt-%Cu reduces the difference between the liquidus and solidus temperatures. It is shown that the added Cu reacts with the Sn content of the solder to form Cu6Sn5 particles in the β-Sn matrix, which are distributed non-uniformly since the Cu content is low. The experimental results also reveal that the growth rate of the solder joint interfacial intermetallic compound layers increases at higher levels of Cu addition. Finally, it is established that adding Cu to the Sn–3Ag–1·5Sb solder not only improves the adhesive strength of the solder joints, but also reduces the rate of degradation of the adhesive strength of the joints during thermal storage.

The influence of copper addition on the formability of AISI 304 stainless steel

The formability of AISI 304 austenitic stainless steel can be enhanced when it is designed to transform to martensite under appropriate strain levels, gaining additional plasticity (transformation induced plasticity). In this work, the effects of a partial substitution of Ni by Cu on the formability of AISI 304 steel were analyzed in terms of microstructure changes during tensile straining. Conventional metallographic techniques aided by scanning probe microscopy were employed to identify and characterize the stress-induced martensitic phases. The results obtained are discussed in terms of the relationship between chemical composition and the stability of austenite, taking into account the stacking fault energy and the characteristics of stress-induced martensite in these steels. It has been observed that the partial substitution of Ni by Cu gave rise to an increase in the strain level required to induce martensitic transformation, resulting in higher maximum uniform elongation and better stretch formability.

Influence of Copper Addition on the Rapid Production of β-FeSi<SUB>2</SUB> by Spark-Plasma Sintering

Thermoelectric materials of Fe 0.91 Mn 0.09 Si 2 + x mass%Cu (0 ≤ x ≤ 1.5) were produced by spark-plasma sintering (SPS) and their thermoelectric properties were measured. The densification was completed in one minute after the temperature reached 900°C. Liquid phase sintering probably occurred during the heating because the addition of copper enabled the specimen to be highly densified. The relative density of the specimen with 1.5%Cu was 94%, while that of the specimen without copper was 90%. Copper also promotes transformation to the β-phase. The e-phase ratio: f e = I e /(I e + I β ) × 100, (I e = intensity of e(210), I β = intensity of β(220, 202)) was calculated from the XRD results in order to easily evaluate the amount of the e-phase in the specimen. In a temperature range from 670 to 730°C, copper allows the annealing time to be shortened by about a half the annealing time without copper. However, an excessive amount of copper and an excessive annealing time had a bad influence on the Seebeck coefficient and the power factor, though the e-phase ratio of the specimen decreased. The optimum composition is Fe 0.91 Mn 0.09 Si 2 + 1%Cu, and the optimum annealing conditions are thirty minutes at 700°C. The power factor of the optimum specimen is about 1.6 times greater than that of the specimen annealed for sixty minutes at 670°C without copper. Thus, it is concluded that the SPS method is extremely effective for the rapid production of β-FeSi 2 .

Glyphosate adsorption on soils of different characteristics.: Influence of copper addition

Results of glyphosate (GPS) adsorption on three soils of different characteristics show that the interaction of this pesticide with the soils was not related to their CEC and clay minerals content, but to the content of iron and aluminum amorphous oxides and organic matter. The presence of Cu in treatment solutions enhanced GPS adsorption, due to several reasons: GPS coordinates strongly to Cu, and Cu–GPS complexes formed seem to have higher ability to be adsorbed on the soil than free GPS; GPS adsorption can take place on sites where Cu was previously adsorbed, acting as a bridge between the soil and GPS; when Cu was present the solution pH decreased, and GPS adsorption increased, since lower pHs lead to the formation of GPS species with lower negative charge, which are adsorbed more easily on the negatively charged soil surfaces.

Influence of copper addition on precipitation kinetics and hardening in Al–Zn–Mg alloy

The influence of the addition of copper on the precipitation behaviour of an Al–Zn–Mg alloy at 160°C has been investigated. Phase transformation has been investigated by differential scanning calorimetry, the precipitation kinetics by small angle X-ray scattering and transmission electron microscopy, and the mechanical properties by microhardness testing. The addition of copper results in an increase in the stability of Guinier–Preston zones formed at room temperature, and in a decrease in the nucleation temperature for the η′ phase. It also results in a decrease in the apparent diffusion coefficient for precipitation, and in an increase in the strengthening ability of precipitates. As a consequence, the copper bearing alloy shows a much higher maximum strengthening ability, and a lower sensitivity to the heating rate to the aging temperature. However, the higher supersaturation of the copper bearing alloy results in a higher quench sensitivity, and at slow quench rates the ternary alloy shows a higher strengthening potential. The experimental data are quantitatively compared with the results of a precipitation model, describing the evolution of precipitate size, volume fraction, and yield stress, and values for physical parameters of the precipitation and strengthening mechanisms are obtained.

The influence of copper addition on the structural properties of sputtered multilayers of the FeSiBCuNb alloy system

As a model system of nanocrystalline FeSiBCuNb alloys, multilayers consisting of nanocrystalline FeSi(Cu) and amorphous FeBNb(Cu) alloys were prepared. In the copper-containing multilayers, all copper diffuses from the amorphous into the FeSi layers during annealing below T A = 500°C. Therefore, copper is not a part of the residual amorphous phase in nanocrystalline FeSiBCuNb.

Influence of copper additions on the crystallization of amorphous FeBSi alloys

The influence of sulphur, copper, manganese, phosphorus, carbon, aluminium, antimony and nickel additives on the crystallization and Curie points of amorphous Fe 80B 14Si 6 alloy was studied by scanning calorimetry and by thermogravimetry. The onset of crystallization in amorphous Fe14at.%B6at.%Si alloys without and with 0.38 at.% CU was studied by means of transmission electron microscopy. A two-step crystallization reaction was observed. The copper addition decreases the onset temperature of the first step of crystallization but has essentially no effect on the second. Magnetic measurements corroborate the observed crystallization behaviour.

Influence of copper addition on electrical and optical properties of amorphous As2Se3

Electrical conductivity and optical absorption of amorphous As2Se3: Cu are investigated as a function of the copper concentration up to 4 at%. Addition of copper up to 0.5 at% increases the density of localized tail states due to the increase of disorder. It is considered that at a copper content of 0.5 at% and more the Fermi level shifts toward the valence band, and that acceptor like states are produced. At a copper content of 1 at% and more, the optical energy gap decreases with the increase of copper concentration and an alloying effect is supposed to take place in the amorphous As2Se3. Die elektrische Leitakhigkeit und der optische Absorptionskoeffizient von amorphen As2Se3: Cu werden in Abhangigkeit vom Kupfergehalt bis zu 4 At% untersucht. Bei Zusatz von Kupfer biszu 0,5 At% nimmt die Dichte der lokalisierten Auslaufer-Zustande bedingt durch die Zunahme der Unordnung zu. Bei Kupfergehalt von 0,6 At% und daruber kann man annehmen, dast das Fermi - Niveau sich zum Valenzband hin verschiebt, und dast Akzeptor-ahnliche Zustinde erzeugt werden. Bei einem Kupfergehalt von 1 At% und daruber, nimmt die optische Energielucke mit zunehmender Kupferkonzentration ab und ein Legierungseffekt setzt im a- As2Se3 ein.

Influence of Copper Addition on Optical Properties of TiO2

Cu‐doped could be considered as a better absorber of sunlight for solar energy conversion. The Cu‐doped has been prepared by anodic oxidation of a Ti‐2.5% Cu alloy. The structural properties of these anodic oxides are examined by electron microdiffraction, XPS, and nuclear microanalysis. The optical properties of both the Ti‐Cu alloy and the anodic films have been determined as functions of the thickness of the oxides. It is concluded that Cu doping of creates an extra state in the forbidden gap of which gives two extra peaks in the absorption spectrum of the oxide. But for solar energy applications, the preparation of the doped oxide by anodic oxidation is not suitable because one does not control the level of impurity.

Influence of copper additions on the basal cleavage in beryllium single crystals at room temperature

In order to study the influence of Cu-alloying on the susceptibility of Be to cleavage along the basal planes, a series of single phase alloys containing up to 5 at. pct Cu in Be were prepared and tested at room temperature by the DCB technique. Copper additions were found to influence strongly the plastic events induced by the shear stresses acting at the crack tip. The crack propagation energy increases with Cu content up to about 1.2 at. pct Cu and decreases with further additions. The maximum value attained at 1.2 at. pct Cu is about seven times that of pure Be. This remarkable initial increase in the crack propagation energy can be accounted for on the basis of the higher energy needed to activate basal and prism slip due to solid solution hardening. In alloys containing more than about 1.2 at. pct Cu, twinning is found to be the most prominent deformation mechanism. The propensity to twin is observed to increase with increasing Cu content, and it is assumed that this reflects a corresponding decrease in the twinning energy. Since twin boundaries are highly susceptible to cleavage cracking, a decrease in the crack propagation energy results which has the effect of increasing the tendency of Be to fracture in a brittle manner in the alloys with higher Cu contents.

Influence of copper additions on some properties of titanium-carbide-steel cermets

1. It has been established that titanium-carbide-steel materials containing copper additions experience precipitation hardening. 2. The addition of copper does not alter the optimum heat treatment temperatures for these materials.

Influence of copper additions on the basal cleavage in beryllium single crystals at room temperature

Influence of copper additions on the basal cleavage in beryllium single crystals at room temperature

Comment on: The influence of copper additions on the superplastic forming behaviour of the Zn-Al eutectoid: By H. Naziri and R. PearceInt. J. mech. Sci.12, 513 (1970)

Comment on: The influence of copper additions on the superplastic forming behaviour of the Zn-Al eutectoid: By H. Naziri and R. PearceInt. J. mech. Sci.12, 513 (1970)