Behavior Of Brass Research Articles

Uticaj kupri jona na koroziono ponašanje mesinga CuZn-42 u prisustvu inhibitora korozije u kiseloj sredini

In this work we are presented our results of investigations of corrosion behavior of CuZn-42 brass in acid sulphate solution, in presence of corrosion inhibitors and cupric ions. Based on the recorded anodic polarisation curves, it was concluded that with increased concentrations of cupric ions, the values of corrosion current densities also increase. The effect of corrosion inhibitors on the corrosion behaviour of brass is analyzed in the work and it is concluded that the concentration of inhibitors is 10-2% shows inhibition effect.

A Constitutive Model Fitting Methodology for Ductile Metals Using Cold Upsetting Tests and Numeric Optimization Techniques

This work documents the development of a tool to perform automated parameter fitting of constitutive material models. Specific to this work is the fitting of a Swift hardening rule and isotropic linear plasticity model to aluminum 2024-T351, C36000 brass, and C10100 copper. Material characterization was conducted through the use of compressive, cold upsetting tests. A noncontact, optical displacement measurement system was applied to measure the axial and radial deformation of the test specimens. Nonlinear optimization techniques were then applied to tune a finite element model to match experimental results through the optimization of material model parameters as well as frictional coefficient. The result is a system, which can determine constitutive model parameters rapidly and without user interaction. While this tool provided material parameters for each material and model tested, the quality of the fit varied depending on how appropriate the constitutive model was to the material's actual plastic behavior. Aluminum's behavior proved to be an excellent match to the Swift hardening rule while the behavior of brass and copper was described better by the linear plasticity model.

Verification of a Thermoviscoplastic Constitutive Relation for Brass Material Using Taylor's Test

This paper presents a methodology to define and verify the dynamic behavior of materials based on Taylor's test. A brass alloy with a microstructure composed mainly of two pure metals that have two different crystal structures, copper (face-centered cubic (fcc)) and zinc (hexagonal closed-packed (hcp)), is used in this study. A combined approach of different principal mechanisms controlled by the emergence and evolution of mobile dislocations as well as the long-range intersections between forest dislocations is, therefore, adopted to develop accurate definition for its flow stress. The constitutive relation is verified against experimental results conducted at low and high strain rates and temperatures using compression screw machine and split Hopkinson pressure bar (SHPB), respectively. The present model predicted results that compare well with experiments and was capable of simulating the low strain rate sensitivity that was observed during the several static and dynamic tests. The verified constitutive relations are further integrated and implemented in a commercial finite element (FE) code for three-dimensional (3D) Taylor's test simulations. A Taylor's test enables the definition of only one point on the stress–strain curve for a given strain rate using the initial and final geometry of the specimen after impact into a rigid surface. Thus, it is necessary to perform several tests with different geometries to define the complete material behavior under dynamic loadings. The advantage of using strain rate independent brass in this study is the possibility to rebuild the complete process of strain hardening during Taylor's tests by using the same specimen geometry. Experimental results using the Taylor test technique at a range of velocity impacts between 70 m/s and 200 m/s are utilized in this study to validate the constitutive model of predicting the dynamic behavior of brass at extreme conditions.

Predicting the corrosion tendency of α-brass in acidic and alkaline tap water

AbstractThis study focuses on the electrochemical behavior of brass in acidic and alkaline tap water. Both conditions were studied using corrosion potential, cyclic polarization and electrochemical impedance spectroscopy. Weight loss experiments were also performed to validate corrosion behavior. It was evaluated from corrosion potential values and Pourbaix diagrams that brass surface was aggressively attacked at lowpHdue to dissolution of zinc-rich phase and solvation of cuprite and zincate at highpHby breakdown of the passive film. Under near neutral conditions the increase in charge transfer resistance corresponded to formation of a stable passive film. Brass exhibited peculiar behavior atpH1 and 12 by showing low charge transfer resistance due to preferential attack of zinc and solvation of copper/zinc rich phases, respectively, as validated by impedance spectroscopy.

Electrochemical behaviour of brass in chloride solution concentrations found in eccrine fingerprint sweat

Abstract In this work, the corrosion properties of α phase brass immersed in concentrations of aqueous NaCl solutions that are typically found in eccrine fingerprint sweat and range between 0.01 M and 0.2 M have been analysed. Analysis methods employed were electrochemical techniques, X-ray photoelectron spectroscopy and optical profiling. For NaCl concentrations

Influence of the Gas Environment on the Transfered Film of the Tribologic Brass (CuZn)/XC48 Steel COUPLE

This paper reports on the influence of environment gas on the brass film and tribological behavior of brass (Cu64Zn36) / steel (AISI 1045) couple. The friction coefficient and the wear rate of brass/steel were measured in ambient air, in pure oxygen at 105 Pa and in vacuum at 5x10-5 Pa. In this study, the mechanism of transfer brass film on steel substrate has been studied with the scanning electronic microscope, the optical microscope and the interferential microscope. The analysis shows that the transfer films properties (roughness, hardness, thickness) depend on the atmospheric conditions. The brass film has an ellipsoidal surface in air and in oxygen with two differents thickness. However, in vacuum, the transfer film produced by a discontinuous adhered particles on the disc. The largest wear rate is obtained when using pur oxygen and the largest friction coefficient µ was measured in ambient air. The smallest friction coefficient and wear rate are obtained in vacuum. The results also showed that the granular film produced in vacuum has a good effect on tribological behavior of brass/steel couple.

Cyclic Behavior and Damage Analysis of Brass under Cyclic Torsional Loading

Fatigue behavior of brass was studied at a constant deformation rate of 5.6 × 10−3 s−1 to understand the cyclic behavior and fatigue life under cyclic torsional deformation. Strains were in the range of 0.35 to 4.2%. In the as-drawn condition, it was found that the cyclic hardening/softening behavior strongly depends on the strain amplitude. For low strain amplitude, cyclic saturation occurred after an initial cyclic hardening stage, but for high strain amplitude, saturation could not be reached. Cyclic stress-strain (CSS) curve showed the presence of three distinct regions with a short quasi-plateau region in the intermediate amplitude range. Quantitative fatigue damage was assessed by microscopic observations of surface cracks.

Modeling of mechanical behavior of brass at high strain rates

Modeling of mechanical behavior of brass at high strain rates

Effects of Zn and Pb as alloying elements on the electrochemical behaviour of brass in borate solutions

The electrochemical behaviour of brasses with various Zn content (5.5–38) and brass (Cu–38Zn) with different Pb content (1.3–3.3) in borate solution, pH 9.0, was investigated. The effects of applied potential and the presence of aggressive Cl− ions were also studied. Different electrochemical methods such as open-circuit potential measurements, polarization techniques and electrochemical impedence spectroscopy (EIS) were used. Increase in zinc content decreases the corrosion rate of brass in borate solution exponentially. Long immersion of leaded brasses and alloys with different Zn content improves their stability due to the formation of a passive film. The passive film formation under open-circuit and potentiostatic conditions proceeds via dissolution–precipitation mechanism. The addition of a low concentration of Cl− ion (0.01 M) to the borate solution increases the corrosion rate of Cu–38Zn due to dezincification. Increase in Cl− ion concentration (0.01–0.2 M) decreases the corrosion rate of the brass exponentially due to formation of insoluble CuCl. For Cl− ion concentrations >0.2 M the corrosion rate of the brass increases again due to the formation of the soluble CuCl2 − complex.

Dissolution of brass 70/30 (Cu/Zn) and its inhibition during the acid wash in distillers

The corrosion behaviour of brass 70Cu/30Zn in deaerated solutions of pure dilute HCl and acidified 4% NaCl of pH 1.8–2 was studied at different temperatures between 25 and 60 °C by the weight loss method. The curves representing the variation of loss in weight with time indicate that there is an induction period followed by a linear relation. Analysis of the solution by the atomic absorption technique and investigation of the surface by scanning electron microscopy indicate that the linear relation begins at a critical value of copper-ion concentration of the corrodent due to autocatalysis. The addition of different concentrations of CuCl2 eliminates the induction period and increases the corrosion rate. The effect of the addition of different concentrations of 2-methyl benzimidazole (MBIA) and Armohib 28 inhibitors on the dissolution of the alloy in both media was tested at 60 °C. MBIA has no effect in the case of acidified 4% NaCl, but with pure dilute HCl the inhibition efficiency in the presence of 300 p.p.m. MBIA amounted to 84.6%. On the other hand, the inhibition efficiency reached 93.4% and 94.6% in the presence of 10 p.p.m. Armohib 28 inhibitor in pure dilute HCl and acidified 4% NaCl, respectively.

Dynamic Constitutive Equations and Behaviour of Brass at High Strain Rates

This paper presents an experimental study of the mechanical properties of brass at high strain rates. The brass tested is the copperzinc alpha-beta and beta two-phase alloy in the cold-worked state. Experiments were conducted using an extended tension split Hopkinson bar apparatus. It is found that, at lower strain rates, the stress-strain curve is smooth, exhibiting no well-defined yield stress, but at higher strain rates the stress-strain curve not only shows a well-defined yield stress but also displays a very pronounced drop in stress at yield. The flow stress is found to increase with increasing strain rate, but the increase is more significant for the yield stress than for the flow stress, showing that the yield stress is more sensitive to the strain rate than the flow stress away from the yield point. Based on the experimental results, empirical strain-rate-dependent constitutive equations are recommended. The suggested constitutive equations provide a reasonable estimate of the strain-rate-sensitive behaviour of materials.

Corrosion Behaviour of brass in nitric acid solutions

Corrosion Behaviour of brass in nitric acid solutions

Electrochemical Behavior of Brass (CuZn 63:37) in Binary Mixtures of N,N-Dimethylformamide and Water

Abstract The electrochemical behavior of brass has been studied In N,N-dimethylformamide (DMF) and water mixtures at 30 C using the potentiostatic polarization technique, weight loss method, and solution analysis. The effects of dissolved oxygen and stirring have also been studied. The dissolution of brass has been found to be cathodically controlled, with the metal being more anodically active in the region of the greater percentage of water. The weight loss and solution analysis reveal preferential dissolution of zinc in the initial stages, which decreases progressively with time.

Effect of benzotriazole on the corrosion and electrochemical behavior of brass and aluminum in cooling water

Effect of benzotriazole on the corrosion and electrochemical behavior of brass and aluminum in cooling water

Precise Experiments on Plastic : Behaviour of Brass under Combined Load

Precise Experiments on Plastic : Behaviour of Brass under Combined Load

Studies in Boundary Lubrication—III: The Wear of Carbon Brushes in Dry Atmospheres

Abstract The dusting wear of carbon brushes is studied in dry nitrogen at atmospheric pressure. The effect of water, oxygen, and carbon dioxide on dusting wear is described, and the results compared with those of investigations carried out under partial vacuum conditions. No effect of current, up to 114 amp per sq in. is found under the conditions studied. It is shown that a highly oriented natural graphite specimen or an oriented graphite brush, operated so that the faces of the cleavage planes rub on a plane rotating copper surface, neither dusts nor produces wear on the copper surface in dry nitrogen. When operated so that the edges of the cleavage planes rub against the plate, rapid dusting wear takes place and the copper surface is deeply scored. The dusting rate of carbon brushes in dry nitrogen against several metals is given. The rate is shown to decrease as the hardness of the metal increases, the behavior of brass being exceptional. It is found to be zero on smooth chromium and rhodium surfaces. On the assumption that an adsorbed lubricant film prevents scoring of the plate by the edges of the graphite crystals, allowing them to be oriented, the results are shown to be consistent with recent theories of solid friction.