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Because of its excellent mechanical qualities and weldability, titanium alloy is used in many different biomedical applications. Wire electrical discharge machining may be used to machine materials with such greater strengths and intricate forms. Using Taguchi-data envelopment analysis-based ranking (DEAR) approach and zinc-diffused coated brass wire electrode to improve Titanium alloy machining was the goal of this research project. The quality metrics that were taken into consideration were surface roughness, kerf width, and material removal rate. Among the selected factors, with an error of 2.7%, the optimal configuration of input factors was determined to be 130 µs (Ton), 40 µs (Toff), 50 V (SV), 6 A (IP), and 8 kg (WT). Due to its relevance in the process of deionization, the Ton is the highest influential parameter for creating quality measurements. [ABSTRACT FROM AUTHOR]

The flanging process is widely used in stamping production: when collar drawing small holes for threads or to increase the stiffness of a draw piece. It can also replace the operation of deep drawing cylindrical draw pieces with a large flange followed by cutting the bottom. The paper discusses the influence of the shape of the punch and the grade of material on load changes at various collar drawing coefficients. Flat, spherical and conical punches and samples made of EN-AW 1050A aluminium, Cu-ETP copper, CuZn37 brass, S235JRG2 steel, X6Cr17 steel and X5CrNi18-10 steel were used for testing. The relative thickness of test pieces was 0.015 (which corresponded to a thickness of 1 mm and a blank diameter of 66 mm). Various collar drawing factors ranging from 0.32 to 0.54 were adopted in the studies. An analysis of the obtained height of collars and wall thicknesses was carried out. The experimental tests were carried out using special tooling mounted on a testing machine with a 20 kN load for 0.5 metrological class. Changes in the force as a function of the displacement of the punches were recorded using Test&Motion software that is commonly applied in research laboratories. Based on the obtained results at various technological parameters, possibility of flanging process was evaluated in industrial conditions. [ABSTRACT FROM AUTHOR]

Aluminium alloys have been one of the leading materials used in aircraft structural components due to their mechanical performance, low density, and different manufacturing and inspection techniques. The mechanical, chemical, and electrical properties of metallic alloys relate to the microstructural arrangement, which depends on the alloying elements and manufacturing parameters. Therefore, this study aims to experimentally develop an Al-2wt.%Ni-0.5wt.%Co alloy as an alternative for aerospace applications, evaluating the main metallurgical aspects influencing mechanical strength. The samples were solidified in brass moulds with four different diameters, allowing four different cooling rates. A statistical analysis of the correlation between microstructural parameters and mechanical properties is proposed to optimise the conditions for obtaining the best mechanical strength. A microstructure with an essentially cellular matrix of the α-Al phase was observed. The tensile strength limit values (σU) of 117 MPa, specific elongation (δ) of 13.8%, and average microhardness of 33 HV were obtained. The Al-2wt.%Ni-0.5wt.%Co alloy exhibits impressive high cycle fatigue performance, with an endurance limit of 91 MPa at 107 cycles, driven by the synergistic effects of Al3Ni for strength and Al9Co2 for enhanced ductility and toughness. [ABSTRACT FROM AUTHOR]

The exploration of unleaded free-cutting Cu40Zn brass with excellent mechanical and tribological properties has always drawn the attention of researchers. Due to its attractive properties combining metals and ceramics, Ti3AlC2 was added to Cu40Zn brass using high-energy milling and hot-pressing sintering. The effects of Ti3AlC2 on the microstructure, mechanical and tribological properties of Cu40Zn-Ti3AlC2 composites were studied. The results showed that Ti3AlC2 could suppress the formation of ZnO by adsorbing oxygen impurity and promote the formation of the β phase by releasing the β-forming element Al to the substrate. The hardness and wear resistance of Cu40Zn-Ti3AlC2 composites increased with increasing Ti3AlC2 content from 0 to 5 wt.%. The proper Ti3AlC2 additive was beneficial to both the strength and plasticity of the composites. The underlying mechanisms were discussed. [ABSTRACT FROM AUTHOR]

The production and characterization of UNS C65620 (CuZn3Fe2Si3) and UNS C87800 (CuZn15Si4) coded alloys were investigated. The alloys poured into the gravity die casting method were hot forged with a ram, followed by stress relief annealing heat treatment. While the formation of Cu4Si, Cu0.83Si0.17 and Cu5Zn8 phases were detected in the structure of the UNS C65620 coded alloy, Cu12.75SiZn2.92 and Cu3Zn intermetallics with the phases given above were observed in the structure of the alloy containing more Zn and Si. The formation of phases containing more Si and Zn resulted in an increase in both the hardness and strength of the UNS C87800 coded alloy, while the decrease in the % reduction of area and the observation of dynamic deformation aging caused the increase in both the wear rate and deformation hardening rate, which led to embrittlement of the alloy. The deterioration of the corrosion resistance of the UNS C87800 coded alloy can be attributed to the formation of Zn-rich corrosion products on the surface during corrosion.

Lacquered brass objects are widely present in scientific and technical heritage collections. Localized atmospheric corrosion occurs on the metal when the coating fails to play its protective role. Although lacquered brass objects are not necessarily endangered by this phenomenon, the presence of dark, unpleasant corrosion spots alters the surface appearance, affecting the readability of the objects. Conservators are therefore frequently asked to clean these surfaces. We hereby present the results of a study conducted in the framework of the CleanLaB (Cleaning of Lacquered Brass) project at the Haute Ecole Arc of Neuchâtel for the cleaning of lacquered brass. This work investigates the effects of several gelled cleaning systems applied on artificially aged, lacquered brass samples to remove the corrosion products without affecting the integrity of the coating. The performance of complexing agents commonly used in conservation was compared on lacquered brass mock-ups coated with shellac resin by means of multiple non-invasive characterization and imaging techniques. The tests included conventional complexing agents like sodium citrate and disodium ethylenediaminetetraacetic acid, as well as a bio-originated system based on deferoxamine, a microbial metal chelator investigated as a green alternative in cleaning formulations.

The existence of striations, and scratches in Abrasive waterjet (AWJ) cutting surface necessitates an exploration of these features for enhancing the cutting accuracy of AWJ machining. This article investigates surface roughness and micro-scratch morphology characteristics on brass cutting surfaces. According to the variation law of surface roughness values, the cutting section can be divided into three regions: the initial region, smooth region, and rough region. Numerous micron-scale scratches were observed in the cutting section. The scratch length, width, and depth values all show an increasing trend as the cutting depth increases, with the scratch length experiencing the greatest growth and variability. The influence of position and traverse speed on scratch size was studied using variance analysis. Furthermore, the length and width of the scratches on the cutting surface are significantly influenced by their position, accounting for 89.19% and 81.13%, respectively. Traverse speed had a minor effect on scratch length and width, accounting for 0.01% and 2.64% respectively. The depth of the scratches is influenced by their position on the cutting surface at a rate of 41.12%, while traverse speed had an impact of 38.10%. Finally, a mathematical method based on standard scores was proposed to assess the quality of the cutting section based on micro-scratch dimension. [ABSTRACT FROM AUTHOR]

Similar to conventional blanking, there are some characteristics, such as rollover, burnish, and fracture on the sides of micro blanked parts, and rollover height and fracture height vary with the blanking clearance. This paper attempts to reveal the effect of blanking clearance on the rollover height. An uncoupled ductile fracture criterion is used to describe the effect of the blanking clearance on the fracture height. The experimental and simulation results show that the increase in hydrostatic stress gradient on the foil around the die edge results in an increase in rollover height. The coefficients of the uncoupled ductile fracture criterion are determined by the method of inverse solution and data fitting. The criterion is evaluated by mean-square error to ensure its validity. This analysis method has been verified by micro brass blanked part. [ABSTRACT FROM AUTHOR]

Information on the flyer deformation during laser impact welding (LIW) is an important aspect to consider when high reliability of the welded components is required. For this reason, accurate numerical models simulating thermal and mechanical aspects are needed. In the present work, the cross-section morphology during LIW of Ti/Brass joints at varying laser pulse energies is modeled by a 2D finite element (FE) model. A hydrodynamic plasma pressure model able to describe the evolution of the pressure load step by step, taking into account the progressive deformation of the flyer, was implemented. Hence, this paper proposes an alternative method to the conventional node concentrated forces or predefined velocity as flyer boundary conditions. The levels of the equivalent plastic strain (PEEQ), shear stress, and critical flyer velocity at the collision point were used as reference parameters to predict the success of the welding bond, distinguishing the welded area from the unwelded area. The model was validated by comparison with the experimental data, which showed the effectiveness of the proposed FE code in predicting the cross-section morphology of the welded materials. Moreover, practical industrial information such as variation in the flyer impact velocity, collision angle, and process temperatures was predicted by varying the process laser pulse energy according to the basic principle of the process. [ABSTRACT FROM AUTHOR]

The current research investigates the effects of materials and riblets on cavitation-induced erosion morphology, depth, and cross-sectional area through experimental approaches. To achieve these aims, the erosion of pure aluminum (1xxxAl or Al) and alpha brass (CuZn37 or CZ108), in the presence and absence of bio-inspired sawtooth riblets, was examined after exposure to multiple collapses of single cavitation bubbles with a wall distance of 1.8 (dimensionless). The results indicate that the erosion morphology resembles a rounded cone with a circular cross-section. Brass provides 21.6% more erosion resistance compared to that of Al in terms of material properties. Furthermore, the erosion for both Al (depth by 3.8% and width by 18.3%) and brass (depth by 7.9% and width by 27.4%) decreases in the presence of riblets compared to the results for flat surfaces. The greater erosion resistance of brass compared to Al is attributed to the superior mechanical stability of brass, making it a potentially suitable alloy for use in propellers and hulls in the shipping industry. In summary, the results reveal that riblet-equipped materials with high mechanical durability are promising erosion-resistant materials for the shipping industry. However, the potential for chemical reactions in a cathodic environment should be addressed to provide a comprehensive perspective in regards to reducing corrosion intensity. [ABSTRACT FROM AUTHOR]

PEO coatings are formed by subjecting a metal substrate to an electrolytic plasma discharge, resulting in the formation of a porous and rough oxide layer. Herein, the significant role of the chemical composition of the electrolyte system and additives in the formation of an oxide coating on brass alloy in the PEO process was investigated. It was observed that the coating created with 8 g/l aluminate, 1 g/l NaOH, and 1 g/l KF electrolyte had higher homogeneity than other coatings. This is because a composite oxide coating of Cu 2 O, ZnO, and AlCuO 2 was formed. Methylene Blue (MB), a widely used dye in various industries, is known to be persistent and environmentally harmful. The photocatalytic activity of the PEO coating on brass for the removal of MB was investigated under visible light exposure. According to the results, the presence of the sample produced in an electrolyte containing 8 g/l Aluminate, 1 g/l NaOH, and 1 g/l KF resulted in a degradation rate of approximately 65 % for MB photodegradation after 6 h of irradiation. The PEO-coated brass shows promising photocatalytic efficiency compared to our research group's PEO-coated TiO 2 coatings, indicating its potential as a photocatalyst. The results highlight that PEO coating on brass could be a potential candidate for photocatalytic and photoelectrochemical applications. [ABSTRACT FROM AUTHOR]

The production and characterization of UNS C65620 (CuZn3Fe2Si3) and UNS C87800 (CuZn15Si4) coded alloys were investigated. The alloys poured into the gravity die casting method were hot forged with a ram, followed by stress relief annealing heat treatment. While the formation of Cu4Si, Cu0.83Si0.17 and Cu5Zn8 phases were detected in the structure of the UNS C65620 coded alloy, Cu12.75SiZn2.92 and Cu3Zn intermetallics with the phases given above were observed in the structure of the alloy containing more Zn and Si. The formation of phases containing more Si and Zn resulted in an increase in both the hardness and strength of the UNS C87800 coded alloy, while the decrease in the % reduction of area and the observation of dynamic deformation aging caused the increase in both the wear rate and deformation hardening rate, which led to embrittlement of the alloy. The deterioration of the corrosion resistance of the UNS C87800 coded alloy can be attributed to the formation of Zn-rich corrosion products on the surface during corrosion. [ABSTRACT FROM AUTHOR]

The relationship between acoustic parameters and the microstructure of a Cu30Zn brass plate subjected to plastic deformation was evaluated. The plate, previously annealed at 550 °C for 30 min, was cold rolled to reductions ranging from 10% to 70%. Linear ultrasonic measurements were performed on each of the nine specimens, corresponding to the nine different reductions, using the pulse-echo method to record the times of flight of longitudinal waves along the thickness axis. Subsequently, acoustic measurements were conducted to determine the nonlinear parameter β through second harmonic generation. Microstructural analysis, carried out by X-ray diffraction, Vickers hardness testing, and optical microscopy, revealed an increase in deformation twins, reaching a maximum at 40% thickness reduction. At higher deformations, the microstructure showed the generation and proliferation of shear bands, coinciding with a decrease in the twinning structure and an increase in dislocation density. The longitudinal wave velocity exhibited a 0.9% decrease at 20% deformation, attributed to dislocations and initial twin formation, followed by a continuous increase up to 2% beyond this point, resulting from the combined effects of twinning and shear banding. The nonlinear parameter β displayed a notable maximum, approximately one order of magnitude greater than its original value, at 40% deformation. This peak correlates with a roughly tenfold increase in twinning fault probability at the same deformation level. [ABSTRACT FROM AUTHOR]

Free-cutting brass is a material whose machinability is improved by the addition of lead. It is used in a wide range of applications because of its high electrical conductivity and antibacterial properties. However, the use of lead is restricted by laws and regulations to reduce environmental damage. Therefore, the lead in free-cutting brass is being replaced by bismuth or silicon. The machinability of lead-free brass, improved by these additives, has been confirmed to be sufficient for milling and turning. However, when drilling deep small-diameter holes in leadless brass, the problem of premature drill breakage occurs due to chips clumping and clogging in the drill flutes. In a previous study, drilling of holes with an aspect ratio of nine was performed using a 1.0 mm diameter cemented carbide drill, and it was confirmed that the addition of trace elements improved the chip breaking and chip evacuation. However, the waveform of thrust force during machining demonstrated a decreasing trend, and the original machining conditions were not attained. In this study, the effect of feed rate on chip evacuation was investigated using a 0.5 mm diameter twist drill, which is subject to severe chip evacuation at high cutting speeds. As a result of examining chip evacuation by varying the feed rate, the chip evacuation exhibited good performance; where bellows-like chips were evacuated under a slow feed rate, and long-pitch chips were evacuated under a high feed rate. In the drilling process using these feed rates with good chip evacuation, 10,000 holes could be drilled, but the shape of the top of the hole was distorted and the straightness was poor at a slow feed rate. In contrast, hole accuracy was good at a high feed rate, further indicating that a high feed rate with long-pitch-shaped chip evacuation is effective for high efficiency when drilling deep holes of small diameters. [ABSTRACT FROM AUTHOR]

To improve the machinability properties of CuZn-alloys, these are alloyed with the element lead. Due to its toxicity, a variety of legislative initiatives aim to reduce the lead content in CuZn-alloys, which results in critical machinability problems and a reduction in the productivity of machining processes. Basically, there are two ways to solve the critical machinability problems when machining lead-free CuZn-alloys: optimizing the machinability of lead-free materials on the material side or adapting the processes and the respective process parameters. In this study, the focus is on material-side machinability optimization by investigating the influence of a targeted variation in the process chain in the material production route. To evaluate the influence of the material production route, the brass alloy CuZn40 (CW509L) was produced in four variants by varying the degree of work hardening and the use of heat treatments, and all four variants were evaluated in terms of their machinability. To evaluate the machinability, the cutting force components, the chip temperature, the chip formation, and the chip shape were analyzed. Clear influences of the material production route were identified, particularly with regard to the chip formation mechanisms and the resulting chip shape. [ABSTRACT FROM AUTHOR]

Copper-containing materials are attracting attention as self-disinfecting surfaces, suitable for helping healthcare settings in reducing healthcare-associated infections. However, the impact of repeated exposure to disinfectants frequently used in biocleaning protocols on their antibacterial activity remains insufficiently characterized. This study aimed at evaluating the antibacterial efficiency of copper (positive control), a brass alloy (AB+®) and stainless steel (negative control) after repeated exposure to a quaternary ammonium compound and/or a mix of peracetic acid/hydrogen peroxide routinely used in healthcare settings. A panel of six antibiotic-resistant strains (clinical isolates) was selected for this assessment. After a short (5 min) exposure time, the copper and brass materials retained significantly better antibacterial efficiencies than stainless steel, regardless of the bacterial strain or disinfectant treatment considered. Moreover, post treatment with both disinfectant products, copper-containing materials still reached similar levels of antibacterial efficiency to those obtained before treatment. Antibiotic resistance mechanisms such as efflux pump overexpression did not impair the antibacterial efficiency of copper-containing materials, nor did the presence of one or several genes related to copper homeostasis/resistance. In light of these results, surfaces made out of copper and brass remain interesting tools in the fight against the dissemination of antibiotic-resistant strains that might cause healthcare-associated infections. [ABSTRACT FROM AUTHOR]

A facile method for preparing superhydrophobic brass mesh is proposed based on electrochemical etching and surface modification. The impact of processing time and the electric potential of the electrochemical etching were studied on the contact angle (CA) of the mesh. The samples were examined using scanning electron microscopy, Energy-dispersive X-ray spectroscopy analysis, X-ray diffraction, and Fourier-transform infrared spectroscopy. The electrochemical etching process caused the decrement of wires' thickness and imposed roughness. Results showed more dissolution of zinc than copper under 3 V of the electric potential and the processing times of 3 and 6 min. The optimum condition of electrochemical etching was obtained under the electric voltage of 3 V for a processing time of 6 min, which led to a CA of 155.5 ± 3.2°. The thickness of the mesh wires decreased by 17.7% due to electrochemical etching in this sample. This sample also showed low adhesion for a water drop. The efficiency of oil/water separation was above 95 for the xylene and ethyl acetate in a batch system. The effect of the flow rate of the oil–water mixture on separation efficiency was also examined. The optimum flow rate was 0.8 ml s−1 with a high separation efficiency of 96.8% for xylene/oil separation. [ABSTRACT FROM AUTHOR]

Lacquered brass objects are widely present in scientific and technical heritage collections. Localized atmospheric corrosion occurs on the metal when the coating fails to play its protective role. Although lacquered brass objects are not necessarily endangered by this phenomenon, the presence of dark, unpleasant corrosion spots alters the surface appearance, affecting the readability of the objects. Conservators are therefore frequently asked to clean these surfaces. We hereby present the results of a study conducted in the framework of the CleanLaB (Cleaning of Lacquered Brass) project at the Haute Ecole Arc of Neuchâtel for the cleaning of lacquered brass. This work investigates the effects of several gelled cleaning systems applied on artificially aged, lacquered brass samples to remove the corrosion products without affecting the integrity of the coating. The performance of complexing agents commonly used in conservation was compared on lacquered brass mock-ups coated with shellac resin by means of multiple non-invasive characterization and imaging techniques. The tests included conventional complexing agents like sodium citrate and disodium ethylenediaminetetraacetic acid, as well as a bio-originated system based on deferoxamine, a microbial metal chelator investigated as a green alternative in cleaning formulations. [ABSTRACT FROM AUTHOR]

Low friction and high wear resistance are critical properties for sliding bearings. In this research, advanced Cu/GO nanocomposite coatings have been developed by a brush plating method to improve the tribological performance of brass-based sliding bearings. A series of brush plating studies under voltages from 2 to 6 V with different GO concentrations (0.2–0.8 g/L) was conducted, and the coating microstructures were characterised by SEM, EDX, GDOES and XRD and the tribological behaviour of the Cu/GO composite coatings were evaluated using dry ball-on-plane tribological tests The experimental results have demonstrated that GO can be successfully introduced into the whole composite coating layer; the Cu/GO composite coatings can reduce the friction of brass and increase its wear resistance by two orders of magnitude, mainly due to the self-lubricating GO added into the coatings. [ABSTRACT FROM AUTHOR]

Phase equilibria were investigated between 200 and 800 °C in the Cu-Zn binary system. Wavelength dispersive spectroscopy (WDS) was performed to determine the equilibrium compositions, and differential scanning calorimetry (DSC) was performed to investigate the solidus and liquidus temperatures and the invariant reaction temperatures of the Zn-rich portion. The β/(α + β) boundary in the Cu-rich portion extended toward the Cu-rich side as the temperature decreased below the A2–B2 order–disorder transformation temperature, and the phase boundaries of the γ, δ and ε phases shifted toward the Cu-rich side. The liquidus temperatures of the ε + liquid were higher than those of the previous report. From the experimental results, the phase diagram of the Cu-Zn binary system was determined in the whole composition range. [ABSTRACT FROM AUTHOR]

Changing the morphology of intermetallic inclusions of two-phase alloyed brass is studied during its heating in a hot deformation temperature range. During heating, the redistribution of elements between silicide inclusions and matrix solution is found to occur, which, in a temperature range of 750–830°С, results in the silicide surface exfoliation and loss of coherence. [ABSTRACT FROM AUTHOR]

This paper aims to investigate the response and local buckling of locally sharp-notched C2700 brass circular tubes (LSN C2700 brass circular tubes) under cyclic bending loads. The study considers four different notch orientations (0°, 30°, 60°, and 90°) and five distinct notch depths (0.2, 0.4, 0.6, 0.8, and 1.0 mm). The results reveal that notch orientation and depth exert minimal impact on the moment–curvature relationship, leading to the formation of stable loops. The ovalization–curvature graphs demonstrate a trend of symmetry, serration, and growth with an increasing number of bending cycles. Additionally, larger notch orientations or smaller notch depths result in reduced ovalization. Furthermore, the double logarithmic coordinates of controlled curvature–number of cycles necessary to induce local buckling reveal five non-parallel lines representing different notch depths when the notch orientation is fixed. Finally, by adopting the formulas for smooth tubes and for locally sharp-notched 304 stainless steel circular tubes (LSN SS304 circular tubes), this study adjusts the related material parameters accordingly. These modifications effectively describe the controlled curvature–number of cycles necessary to induce local buckling for LSN C2700 brass circular tubes with different notch orientations and depths under cyclic bending, demonstrating reasonable agreement with the experimental results. [ABSTRACT FROM AUTHOR]

In the current work, a novel medium entropy copper alloy was designed with the aim of avoiding the use of expensive, hazardous or scarce alloying elements and instead employing widely available and cost-effective alternatives. In order to investigate this unknown region of multicomponent alloy compositions, the thermo-physical parameters were calculated and the CALPHAD method was utilized. This led to the design of the Cu50Zn25Al20Sn5 at. % (Cu53.45Zn27.49Al9.08Sn9.98 wt. %) alloy with a relatively low density of 6.86 g/cm3 compared with conventional brasses. The designed alloy was manufactured through vacuum induction melting, producing two ingots weighing 1.2 kg each, which were subjected to a series of heat treatments. The microstructural evolution of the alloy in the as-cast and heat-treated conditions was assessed through optical and scanning electron microscopy. The hardness of the as-cast and heat-treated alloy at room temperature was also studied. The alloy was characterized by a multiphase microstructure containing a major Cu-rich (Cu–Zn–Al) matrix reinforced with a secondary Zn-rich (Zn–Cu) phase and pure Sn. In terms of mechanical properties, the developed alloy exhibited high hardness values of roughly 378 HV0.2 and 499 HV0.2 in the as-cast and heat-treated conditions, respectively. [ABSTRACT FROM AUTHOR]

The aim of the article was to determine the impact of crushed condition (work hardening) on the effectiveness of the vibratory machining. The vibratory machining processing was carried out in two steps. The first step consisted of mechanical abrasion and remove oxides from the surface of the workpieces with abrasive media. While in the second step, smoothing - polishing with metal media was performed. Vibratory polishing also strengthened the treated surfaces. The test results were compared for samples in the crushed state (work hardening, plastic processing) and samples subjected to recrystallization annealing heat treatment. Mass losses, changes in the geometric structure of the surface and changes in the hardness of the machining surfaces were analyzed. Samples subjected to recrystallization, as compared to the samples in the state after work hardening-plastic working, are characterized by a slightly higher arithmetic mean surface roughness and lower surface hardness than for analogous processes for samples not subjected to heat treatment. Heat treatment of annealing allows to remove the effects of crushing and thus it is possible to obtain larger mass losses. Smaller burrs dimensions were obtained for samples after the heat treatment – annealing than after work hardening.

In the present study, the microstructure, mechanical and wear characteristics of commercial Cu-30Zn brass alloy were developed by an equal channel-angular process (ECAP) using a particular die in constant dimensions. The ECAP process was experimentally conducted at room temperature using (1-4) passes in route C with lubricating conditions. Also, the post-annealing treatment at 350 oC has been done for some brass samples, which were deformed with four passes. Findings revealed that by conducting the ECAP, a significant reduction in the grain size of the deformed brass samples is achieved compared to the as-received alloy. The grain refinement increased with the increasing number of ECAP passes. However, the post-annealing treatment increased the grain size of the deformed brass alloy, but still it was lower than the as-received alloy. Moreover, the mechanical performance, i.e. micro-hardness and strength, was significantly enhanced after the ECAP. The samples processed with three passes presented the highest hardness value (237 HV) and mechanical strength (UTS= 692 MPa, and YS= 542 MPa) due to the homogeneous strain hardening and substantial grain refinement throughout the ECAP process. However, the micro-hardness and mechanical strength of brass alloy decreased after post-annealing treatment compared to those of the ECAP deformed samples. The elongation to failure also decreased greatly with increasing the number of passes of ECAP. Additionally, the wear resistance of the investigated samples increased significantly after increasing the number of ECAP passes compared to the as-received alloy. The highest wear resistance has been achieved for samples deformed by three and four passes of ECAP due to the considerable grain size refinement and higher hardness. However, a slight increase in the wear rate occurred after post-annealing treatment on a brass alloy sample processed with four passes due to the increase in grain size.

Abstract The hexane extract of Persea schiedeana Ness (PSN) was analyzed as corrosion inhibitor for the brass surface immersed in 0.5 M HCl. Fourier-transform infrared spectroscopy and a gas chromatographic (GC) and mass spectrometric (MS) were used to identify the PSN extract’s functional groups and compound constituents. The functional groups identified were $${\text{C}}{\text{H}}_{3}$$ CH 3 and $${\text{C}}{\text{H}}_{2}$$ CH 2 functional alkyl groups, $$\text{C=O}$$ C=O stretching vibration of aldehydes, ketones, and carbonyl groups. The GC/MS determined the presence of fatty acids in the PSN extract, where palmitic acid, oleic acid, and ethyl oleate were the major constituents. Electrochemical characterizations were conducted to observe the effect of PSN as corrosion inhibitor on the brass surface. The R p and R n calculated from EIS and ENA give the same behavior. Based on the OCP behavior, it was determined that the PSN works as a mix inhibitor, affecting both anodic and cathodic reactions. The corrosion current density (I corr) suggests that the extract of PSN reduces the corrosion rate of the brass with efficiencies above 90% for all concentrations. The efficiency obtained for each PSN concentration was attributed to forming a corrosion scale of $${\text{CuO}}$$ CuO and $${\text{C}}{\text{u}}_{2}{\text{O}}$$ Cu 2 O , which reacted with the carboxyl group to form copper carboxylates on the metal surface.

This paper presents the results of computer modeling of preliminary heat treatment and radial-shear rolling of L63 brass in the Deform program by cellular automata method. Quenching and annealing were simulated as pre-heat treatment modes. Radial-shear rolling consisted of three passes with a compression of 3 mm per pass. The variable parameters were the roll rotation speed (40 rpm, 70 rpm and 100 rpm) and the workpiece heating temperature before rolling (500°C and 700°C). It was found that the most effective mode of preliminary heat treatment of L63 brass is annealing at a temperature of 500°C. The most rational value of the heating temperature of the workpiece before rolling is 500°C, since in this case, at all selected speeds the recrystallization process does not start, which contributes to intensive grain grinding. An increase of roll rotation speed causes additional deformation heating, which contributes to recrystallization and a decrease of grain grinding intensity. [ABSTRACT FROM AUTHOR]

For the US-India bilateral relationship, the first four months of 2024 were a repeat of the last three years: the differences in attitudes toward Cold-War era partnerships resurfaced and made difficult maintaining the calm in bilateral relations. There were significant strides in the economic and trade front. The security relationship, however, was marred by the dispute over the killing of Khalistan separatist, designated as a terrorist by India. Washington diplomatically backed India vis-a-vis China's belligerent actions such as renaming Indian towns by publicly speaking out against it and top military brass made visits to India in a show of support for the growing security cooperation between the two democracies. The election hysteria in India, the heated rhetoric, and polemical statements in the election campaigns of major India political parties provided fodder for the Western press to raise concerns about the supposed "values-based" partnership with India. While not as hyperbolic in nature, US election campaigning dragged India into the mud, with President Biden lumping Japan and India in with Russia and China in a reference to nations that were "xenophobic" and restrictive to immigrants. [ABSTRACT FROM AUTHOR]

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With using of a dispersed-filled gasifying model, it is possible to inoculate the cast brass of the G-CuZn15Si4 (DIN) alloy with intermetallic FeCr, known in the alloys of the binary Fe–Cr system as the σ phase, and to obtain the test castings. With the use of x-ray spectral microanalysis, the chemical composition of cast samples is determined before and after the process of inoculation of the matrix melt with dispersed intermetallic FeCr. The results of x-ray spectral microanalysis show that the cast composite includes Fe and Cr within 1% that vary along the height of the cast sample, while the chemical composition of the control casting contains half as much Fe and Cr is not detected at all. The metallographic analysis of G-CuZn15Si4 cast brass after inoculation make it possible to detect the inclusions of the σ-phase in the field of the metallographic section that is a sign of the microstructure of the zero-dimensional cast composite material of the Cu–FeCr system, while the micro-structure of the control casting is characteristic of G-CuZn15Si4 cast brass. The results of mechanical tests of cast samples and their wear tests under dry-friction conditions allow us to come to the conclusion that the hardness of G-CuZn15Si4 cast brass, which is determined according to the Brinell scale, and its tribotechnical characteristics depend on the height of casts of both types, and on the same properties of cast of the sample after inoculation with dispersed intermetallide FeCr is affected by Fe and Cr concentrations. Graphical interpretation of the experimental data shows that the mechanical and tribotechnical properties of brass castings after the process of inoculation of the matrix melt by the σ phase significantly exceed the similar characteristics of G-CuZn15Si4 cast brass before inoculation. [ABSTRACT FROM AUTHOR]

Purpose: Skin collimation is a useful tool in electron beam therapy (EBT) to decrease the penumbra at the field edge and minimize dose to nearby superficial organs at risk (OARs), but manually fabricating these collimation devices in the clinic to conform to the patient's anatomy can be a difficult and time intensive process. This work compares two types of patient‐specific skin collimation (in‐house 3D printed and vendor‐provided machined brass) using clinically relevant metrics. Methods: Attenuation measurements were performed to determine the thickness of each material needed to adequately shield both 6 and 9 MeV electron beams. Relative and absolute dose planes at various depths were measured using radiochromic film to compare the surface dose, flatness, and penumbra of the different skin collimation materials. Results: Clinically acceptable thicknesses of each material were determined for both 6 and 9 MeV electron beams. Field width, flatness, and penumbra results between the two systems were very similar and significantly improved compared to measurements performed with no surface collimation. Conclusion: Both skin collimation methods investigated in this work generate sharp penumbras at the field edge and can minimize dose to superficial OARs compared to treatment fields with no surface collimation. The benefits of skin collimation are greatest for lower energy electron beams, and the benefits decrease as the measurement depth increases. Using bolus with skin collimation is recommended to avoid surface dose enhancement seen with collimators placed on the skin surface. Ultimately, the appropriate choice of material will depend on the desire to create these devices in‐house or outsource the fabrication to a vendor. [ABSTRACT FROM AUTHOR]

The application of Mott–Schottky (M−S) analysis of impedance data to sub–micro samples extracted from the corrosion patina of copper, bronze, and brass archaeological artifacts attached to graphite electrodes is described. The corresponding theoretical approach is developed to account for the contribution of the composition and structure of the corrosion patina and the effect of the bare graphite substrate. Experimental data in contact with 0.10 M Na2SO4 aqueous solution at pH 6.28 are consistent with the p‐type semiconducting nature of the main copper corrosion products, cuprite, and tenorite. The values of the apparent flat band potential and the slope of the M−S plots allow archaeological samples to be grouped according to their M−S parameters (slopes and intercepts). Assuming equivalent conditions of corrosion, the resulting grouping is judged to be dependent on the composition, and/or method of manufacture, and/or age. Studied samples include Renaissance statues from the Hofkirche in Innsbruck and a variety of objects from museums and Archaeological Heritage Office (soprintendenza) in Austria (Bad Aussee, Johanneum Graz, and the Tyrolean State Museums), and Italy (Genoa and San Remo), dating from the Bronze Age to the 18th century. Complementary data are provided by voltammetry of immobilized particles. [ABSTRACT FROM AUTHOR]

The article investigates the effect of combined thermomechanical processing, including pre-heat treatment and radial-shear rolling on the brass microstructure evolution and the microhardness change. The microstructure analysis of heat-treated samples according to various modes showed that the most optimal heat treatment before radialshear rolling for L63 brass is annealing at a temperature of 500 °C. As a result of combined thermomechanical processing, a gradient structure was obtained, so in the resulting rods with a diameter of 16 mm in the surface layer, a structure with an average grain size of 9 μm was obtained. In rods with a diameter of 12 mm, a fine--grained, equalgrained structure of 3 µm was obtained in the surface layer. [ABSTRACT FROM AUTHOR]

In this study, the hot deformation and formability behaviour of commercially Brass sheet under uniaxial and multiaxial loading conditions at a wide range of temperatures (room temperature −773 K) have been investigated by experiments and theoretical modelling. Uniaxial tensile test and Nakazima test at different test temperatures have been conducted. Different constitutive models, namely, Johnson-Cook (JC) model, modified Zerilli–Armstrong (m-ZA) model, modified JC model, integrated Johnson Cook and Zerilli–Armstrong (JC-ZA) model, have been used to understand the prediction behaviour of flow stress of Brass. Further anisotropic yield criteria, namely, Hill'48 and Barlat'89 yield functions have been utilised for yield loci prediction. From Nakazima test, the experimental forming limit diagram has been plotted. Other formability parameters, namely, limit dome height, thickness distribution, and strain distribution have been analysed. The theoretical FLD by Marciniak Kuczynski (MK) model. By employing the uniaxial constitutive models, anisotropic yield criteria have been investigated. The predicted MK-FLD coupled with the JC-ZA model and Barlat'89 yield criteria shows good agreement with measured experimental FLD. [ABSTRACT FROM AUTHOR]

The aim of the article was to determine the impact of crushed condition (work hardening) on the effectiveness of the vibratory machining. The vibratory machining processing was carried out in two steps. The first step consisted of mechanical abrasion and remove oxides from the surface of the workpieces with abrasive media. While in the second step, smoothing - polishing with metal media was performed. Vibratory polishing also strengthened the treated surfaces. The test results were compared for samples in the crushed state (work hardening, plastic processing) and samples subjected to recrystallization annealing heat treatment. Mass losses, changes in the geometric structure of the surface and changes in the hardness of the machining surfaces were analyzed. Samples subjected to recrystallization, as compared to the samples in the state after work hardening-plastic working, are characterized by a slightly higher arithmetic mean surface roughness and lower surface hardness than for analogous processes for samples not subjected to heat treatment. Heat treatment of annealing allows to remove the effects of crushing and thus it is possible to obtain larger mass losses. Smaller burrs dimensions were obtained for samples after the heat treatment -- annealing than after work hardening. [ABSTRACT FROM AUTHOR]

In the electric discharge machining process, the material is separated from the surface of the work piece by an electric spark, and in the presence of the dielectric material and tool electrode, changes are made on the surface of the work piece. In this project, we investigated the effect of dielectric material and brass tool electrode diffusion on the surface of carbon steel workpiece by means of quantmetric analysis, X-ray diffraction and electrochemical impedance spectroscopy. The effect of the parameters such as electric current intensity (I), pulse on time (ton), pulse off time (toff) and machining time (τ) on the composition of work peace, microstructure and electrochemical corrosion of machined work peace, were investigated. The results of quantmetric analysis showed that with the increase of machining parameters, the amount of diffused copper (from brass tool electrode) and carbon (from pyrolysis of flashing dielectric material) on the surface of machined carbon steel was increased. X-ray diffraction results confirmed that the formation of different phases such as Fe1.92C0.08, Cu4, Cu2 and Fe2 on the surface of workpiece, which was accordance with the quantmetric results. Electrochemical studies showed that during the EDM process, the electrochemical corrosion resistance was increased. [ABSTRACT FROM AUTHOR]

In the present study, the microstructure, mechanical and wear characteristics of commercial Cu30Zn brass alloy were developed by an equal channel-angular process (ECAP) using a particular die in constant dimensions. The ECAP process was experimentally conducted at room temperature using (1-4) passes in route C with lubricating conditions. Also, the postannealing treatment at 350 oC has been done for some brass samples, which were deformed with four passes. Findings revealed that by conducting the ECAP, a significant reduction in the grain size of the deformed brass samples is achieved compared to the as-received alloy. The grain refinement increased with the increasing number of ECAP passes. However, the postannealing treatment increased the grain size of the deformed brass alloy, but still it was lower than the as-received alloy. Moreover, the mechanical performance, i.e. micro-hardness and strength, was significantly enhanced after the ECAP. The samples processed with three passes presented the highest hardness value (237 HV) and mechanical strength (UTS= 692 MPa, and YS= 542 MPa) due to the homogeneous strain hardening and substantial grain refinement throughout the ECAP process. However, the micro-hardness and mechanical strength of brass alloy decreased after post-annealing treatment compared to those of the ECAP deformed samples. The elongation to failure also decreased greatly with increasing the number of passes of ECAP. Additionally, the wear resistance of the investigated samples increased significantly after increasing the number of ECAP passes compared to the as-received alloy. The highest wear resistance has been achieved for samples deformed by three and four passes of ECAP due to the considerable grain size refinement and higher hardness. However, a slight increase in the wear rate occurred after post-annealing treatment on a brass alloy sample processed with four passes due to the increase in grain size. [ABSTRACT FROM AUTHOR]

In industrial water systems, the occurrence of biofilm-associated pathogenic free-living amoebae (FLA) such as Naegleria fowleri is a potential hygienic problem, and factors associated with its occurrence remain poorly understood. This study aimed to evaluate the impact of four cooling circuit materials on the growth of N. fowleri in a freshwater biofilm formed at 42◦C and under a hydrodynamic shear rate of 17 s−1 (laminar flow): polyvinyl chloride, stainless steel, brass, and titanium. Colonization of the freshwater biofilms by N. fowleri was found to be eective on polyvinyl chloride, stainless steel, and titanium. For these three materials, the ratio of (bacterial prey)/(amoeba) was found to control the growth of N. fowleri. All materials taken together, a maximum specific growth rate of 0.18 ± 0.07 h−1 was associated with a generation time of ∼4 h. In contrast, no significant colonization of N. fowleri was found on brass. Therefore, the contribution of copper is strongly suspected. [ABSTRACT FROM AUTHOR]

The shot-to-shot measurement uncertainty restricts the application of laser-induced breakdown spectroscopy (LIBS) technically, to a certain extent. In order to further deepen the understanding of spectral stability, in this paper, the effects of the laser's focus depth, the delay of the spectrometer, and the position of the spectrum collection on the spectral stability were carefully researched. Moreover, the dynamic characteristics of plasma were studied at different laser focusing depths. Research has found that the morphological changes of plasma are relatively stable, without significant changes, despite varying depths of laser focus on the sample surface. In addition, it was found that stable elemental emission spectra can always be obtained in the early plasma aggregation region. [ABSTRACT FROM AUTHOR]

Titanium carbide materials are introduced into manufacturing industries for the reinforcement and surface protection of base materials due to their substantial ability to withstand severe environments, which include sliding wear, corrosion, and mechanical failures. A thin film of titanium carbide (TiC) is coated onto brass and copper substrates using the radio frequency magnetron sputtering (RFMS) deposition method. The coating process is carried out at constant processing parameters, which include a sputtering power of 200 W, a temperature of 80 °C, a deposition time of 180 min, and an argon (Ar) gas flow rate at 10 standard cubic centimetres per minute (SCCM). The coating, together with the base materials, is modelled and its behaviours are simulated using ANSYS Workbench R19.2 Academic, supported by Mechanical APDL solver for nonlinear finite element analysis (FEA). The deformation, equivalent stress–strain characteristics, and elastic–plastic properties of the coating are determined at applied loads of 60 N and 25 N and coefficients of friction (CoF) of 0.25 and 0.38 for the thin film deposition on brass and copper substrates. The sliding distance and the speed of the alloy steel ball used during the sliding wear operation are found to be 3 mm and 4 mm/s, respectively. The sliding wear modelling and simulation process are, however, designed for the ball-on-flat (BoF) wear technique with a dry sliding approach. Therefore, BoF wear simulations are also performed on titanium carbide–brass (TiC-Br) and titanium carbide–copper (TiC-Cu) conjugates for the evaluation of surface engineering applications such as cutting tools and in automotive, aerospace, thermomechanical, and biomedical fields. The ball used for the FEA wear simulation is made from alloy steel material (AISI 52100) with a radius of 3.175 mm. [ABSTRACT FROM AUTHOR]

Introduction/purpose of the research: Latent fingermarks can be found on the crime scene on various surfaces and made visible by different forensic methods. As this evidence can often be found on brass surfaces (ammunition casings, decorative items, etc.) the paper discusses the possibilities of applying electrochemical deposition of nickel on brass. The condition for the application of this technique is the existence of a conductive substrate. Fatty components of latent fingermarks have insulating properties and prevent the electrodeposition process. Methods: Experimental thin rectangular pieces of brass foil were used as substrates for latent fingermarks. Samples were degreased in acetone and ethyl alcohol, rinsed in deionized water, and dried in a stream of compressed air before leaving the fingermarks. To enhance the presence of sweat on friction ridges, the hand was placed in the silicone glove for five minutes. A slight touch of the index finger was left on the tiles. Fingermarks were developed on brass samples by fingerprint powder and the electrochemical deposition of nickel on another brass surface simultaneously. In order to obtain the best possible evidence, the parameters affecting the deposition rate (current density, deposition time) were changed until a clear fingermark was obtained. Results: The fingermarks were compared visually using a magnifying glass with illumination to observe the contrast between the papillary lines and the interpapillary space and the characteristic details (minutiae). The optimal results were achieved with the current density (deposition rate) of 50mA/cm2 for 10s. Conclusion: Electrochemical deposition of nickel on brass is an applicable technique for developing latent fingermarks with certain limitations.

The article investigates the effect of combined thermomechanical processing, including pre-heat treatment and radial-shear rolling on the brass microstructure evolution and the microhardness change. The microstructure analysis of heat-treated samples according to various modes showed that the most optimal heat treatment before radialshear rolling for L63 brass is annealing at a temperature of 500 °C. As a result of combined thermomechanical processing, a gradient structure was obtained, so in the resulting rods with a diameter of 16 mm in the surface layer, a structure with an average grain size of 9 μm was obtained. In rods with a diameter of 12 mm, a fine–grained, equalgrained structure of 3 μm was obtained in the surface layer.

The current study investigates the adsorption properties of a novel heterocyclic compound, 13-(4-chlorophenyl)-3, 3-dimethyl-3, 4-dihydro-1H-indazolo[1,2-b] phthalazine 1,6,11(2H,13H)-trione (DDIP), as an inhibitor against the oxidation of brass in hydrochloric acid solution. The experimental investigation included several methods, including EIS and PDP. The inhibition efficiency of the compound followed the order of 90.0%. The adsorption process of this inhibitor on the brass substrate followed the Langmuir adsorption model. SEM/EDS and XRD techniques were utilized to analyze surfaces, revealing the presence of a protective film overlaying the brass substrate. In addition, the results of DFT calculations of the DDIP compound revealed the existence of many active sites on the brass surface, facilitating the adsorption of our inhibitor. [ABSTRACT FROM AUTHOR]

The challenging characteristics of Inconel 617 (IN617), such as its modest modulus of elasticity, heightened chemical reactivity, and low thermal conductivity, pose difficulties in employing conventional machining methods for this material. This complexity is further amplified when considering the specific requirements for applications in aerospace. Consequently, electric discharge machining (EDM) emerges as a preferred approach for working with this alloy. However, inherent challenges within EDM, specifically electrode wear rate (EWR) and dimensional overcuts, limit its efficacy. To address these issues, a comprehensive exploration of the potential of powder-based additives in waste cooking oil (WCO) against cryogenically treated brass electrode material has been undertaken. The investigation holds pivotal importance because the careful choice of an optimal dielectric plays a significant role in affecting the heat input to the electrode, thereby influencing the melting/vaporization and tool wear of the electrode. It is essential to highlight that these considerations have not been adequately addressed in the current body of literature. The experimentation employs the Response Surface Methodology (RSM) experimental design. The findings indicate that the shallow cryogenically treated (SCT) brass electrode exhibited exceptional performance, yielding the lowest values for electrode wear rate (EWR) at 1.49 mg/min and dimensional overcuts (OC) at 0.01 mm. These results are notably superior, surpassing the least values obtained with the deep cryogenically treated (DCT) brass electrode, showcasing a 202.68% improvement in EWR and a 2.33% improvement in OC. [ABSTRACT FROM AUTHOR]

Cu–Zn (brass) materials are widely used in drinking water equipment, including valves, taps, and fittings. However, this brass suffers significant corrosion when buried in aggressive soil. The aim of this study is to investigate the corrosion resistance of three α-brasses (Br1, Br2 and Br3) buried in aggressive soil of the MNASRA region, located in the province of Kenitra, north-west Morocco. This study was carried out by means of potentiodynamic polarization (PDP), electrochemical impedance spectroscopy (EIS), and open circuit potential (OCP) measurements. A pilot plant was designed to simulate the environment in which the materials were used, and the same materials were buried on the site where they were used for a period of two years. The results show an increase in i corr from 3050 at 24 h to 5400 μA cm−2 at 2016 h for Br3 and from 1330 to 2550 μA cm−2 for Br 2. However, Rp decreases from 181.9 to 2.8 kΩ cm2 for Br3 and from 489.9 to 85.2 kΩ cm2 for Br 2 , indicating that the Br3 and Br2 alloys have undergone significant corrosion in the aggressive soil respectively. Where as a decrease in i corr from 1.280 at 24 h to 0.430 μA cm−2 at 2016 h for Br1. Nevertheless, Rp increased from 192.1 to 881.7 kΩ cm2 indicating an improvement in corrosion resistance due to the formation of a denser protective film on its surface. Moreover, the results show that the presence of a high phosphorus (P) and aluminum (Al) content with a lower percentage of iron (Fe) has a beneficial effect and leads to good corrosion resistance. These results are in agreement with the SEM/EDS and XRD analyses, as well as with the results obtained on-site after two years of immersion by SEM and OP analyses. [ABSTRACT FROM AUTHOR]

The structure, texture, and mechanical properties of a C27400 brass (63% Cu–37% Zn) after alternating elastic–plastic deformation were studied. A 3-mm thick brass strip after softening annealing was subjected to alternating bending through one pass (19 bending acts) using an ARKU 25/21 precision roller straightener. Electron microscopy, x-ray texture analysis, microhardness measurements, and tensile testing were used to characterize the material. It has been established that the alternating bending leads to an increase in the yield point of a thick strip by 62% and the ultimate tensile strength by 12%, while the relative elongation is slightly reduced from 57 to 52%. Such a set of properties is provided by the grain structure refinement through the twinning mechanism; after alternating bending, the average grain size decreases more than 2 times. The contribution of different layers of the strip to the overall hardening is estimated. The anisotropy of the mechanical properties and its relation to texture was studied. [ABSTRACT FROM AUTHOR]