Aluminum Brass Research Articles

Steel tubular friction damper and vibration reduction effects of double-layer reticulated shells

A steel tubular friction damper (STFD) is proposed for vibration reduction in large-span spatial structures. The effects of the amplitude of the applied displacement, the pre-tightening force of the high-strength bolts, and the material of the friction plates on the hysteretic behaviour of the STFD are analysed experimentally. The single-cycle energy consumption increases and the equivalent stiffness decreases with increasing displacement amplitude. In addition, the single-cycle energy consumption and equivalent stiffness of the STFD increase with increasing pre-tightening force. Both the single-cycle energy consumption and the equivalent stiffness of the STFD with aluminium alloy or brass friction plates are larger than that of the STFD with steel friction plates. Then, a mechanical model of the STFD is established for further numerical analysis. Several structural members in a 40-m-span double-layer reticulated shell are replaced with STFDs to provide vibration reduction. Optimal arrangement of STFDs is studied based on additional modal damping ratio. The effects of the replacement rate, earthquake intensity and various ground motions on the vibration reduction effect are investigated via numerical analyses. The reduction ratio first increases and then decreases with increasing replacement rate, and the best performance is observed at a replacement rate of 10%. The vibration reduction effect of the STFDs is more obvious for strong ground motions than for weak ground motions. Under various ground motions, the vibration reduction effect of the STFDs is better for the two ordinary ground motions than for the four long-period ground motions selected herein.

Simulation Study on Erosion Wear Rule of Aluminium Brass Throttling Ring of Artillery Based on Finite Element Method

Erosion wear is the main failure cause of the throttling ring in artillery, which will lead to the reduction of the reliability of the throttling ring, which also will lead to degradation of the performance of recoil brake. According to the working conditions and environmental characteristics of the throttling ring, the finite element model of the erosion wear of the throttling ring is established, and the erosion wear simulation test is carried out to study the erosion wear rules of the throttling ring under different influencing factors, so as to evaluate the reliability of the throttling ring reasonably. It is of great theoretical and practical value to obtain the reliability information of the throttling ring under different working conditions and to ensure the normal performance of the recoil brake.

Study on Aging Treatment Temperature of a Special Aluminum brass

Aging treatment of ZCuZn25Al6Fe3Mn3 was conducted by muffle furnace. We studied the variation of the microstructure and properties of ZCuZn25Al6Fe3Mn3 with the increase of aging temperature. We discovered that the microstructure consists of an equiaxed β phase + a star-like Fe phase + a finely distributed phase of the dispersed phase. No distributed phase was observed when the aging temperature was low. As the aging temperature rises, the punctate phase appears, and the number of punctate phases is the highest at 500 °C . Above 500 °C, continue to raise the temperature, point-like phase aggregation grows into granular phase. As the aging temperature rises, the hardness of the alloy rises first and then decreases, the weight loss of the alloy decreases first and then rises. At 500°C, the hardness of the alloy is the highest, reaching 263 HV, and the weight loss is the smallest, about 0.3990 g.Observing the wear morphology, the wear mechanism under dry friction conditions is known as abrasive wear and adhesive wear. The optimum aging treatment process for ZCuZn25Al6Fe3Mn3 is 500 °C × 2 h air cooling.

Signal enhancement of laser-induced breakdown spectroscopy on non-flat samples by single beam splitting.

A single-beam-splitting approach was employed to enhance the signal intensity of LIBS under the extreme condition of laser beam grazing the surface of non-flat samples. Examining the time-integrated emission spectra shows that ISplit/ISingle enhancement factors of 2.5 and 3.5 were achieved at the laser energy of 33 mJ for aluminium alloy and brass, respectively. This factor first increases, reaches its maximum at 33 mJ, and drops gradually with the laser energy further increased. The mechanisms behind the enhanced optical emission and the enhancement factor evolution are discussed by using the proposed laser ablation model and laser-supported detonation (LSD) wave model, respectively. Examining the time-resolved emission spectra show that enhancement effect exists across all the plasma expansion process and the split beam mode allows for a longer plasma lifetime. A remarkable feature is that the trailing phenomenon emerging in the single beam mode vanishes due to the interaction between the plasmas generated by the grazing incident and normally incident laser beams in the split beam mode. The underlying cause is probably that the plasma plume produced by the normally incident laser beam prevents the grazing incident laser beam from further propagating and ablating the sample surface below. These findings not only give an insight into the plasma generation and evolution at grazing incidence of laser beam on sample surface but also provide a more reliable method for outdoor LIBS measurement of irregular samples.

Effect of Electric Pulse Treatment on the Corrosion Resistance of HAl52-2 Aluminum Brass

In this work, the effects of electric pulse treatment (EPT) on the corrosion resistance of HAl52-2 aluminum brass has been investigated using electrochemical workstation, scanning electron microscope and X-ray diffraction. The results have shown that after EPT, the corrosion potential increased and the corrosion current density decreased. At the same time, the diameter of the capacitive reactance arc of the HAl52-2 aluminum brass after EPT was 5 ~ 6 times of the original sample, and the thickness of dezincification layer was reduced from 59.2 µm to 50.2 µm by 84.8%. The aluminum brass alloy with EPT has demonstrated better corrosion resistance of than the original sample.

Multi-pass friction stirred clad welding of dissimilar joined AA6061 aluminium alloy and brass

Tool steels are commonly used to cut metal materials due to their distinctive hardness, resistance to abrasion and deformation. However, tool steels are difficult to be joined using conventional fusion welding process. In this study, a thixotropic property of metal was utilised to butt-join an AISI D2 tool steel by using uncommon direct partial re-melting (DPRM) method. A high frequency of induction heating is used to apply the DPRM method. From the recent study, there are many methods in achieving the globular microstructure with the success of semi-solid joining process. Though, very less information on the microstructural effect of semi-solid joining on the mechanical properties was reported. This study aims to analyse the effect of uniaxial force on the microstructural evolution and mechanical properties of the thixo-joint of D2 tool steel. The microstructural analysis showed the diffusion occurred between the grains of the thixo-joint sample with 2.5 N uniaxial force. The maximum strength of the thixo-joint sample with force was 652 MPa. This was slightly higher than the as-received sample and the thixo-joint sample without force. The average hardness value of the thixo-joint sample was 400 HV due to the transformation of ferrite to the metastable austenite.

Analytical and numerical modelling of open-die forging process for elliptical cross-section of billet

The present work proposes a novel analytical solution for open-die forging for the billet of elliptical cross-section. From design and evaluation, moreover, from industrial prospective, in order to overcome the limitations and complexities of mathematical modelling for complex shape billets, the numerical simulation technique has also been demonstrated to establish and exploit the potential of commercially available finite element analysis (FEA) software. To start with, testing of fundamental material properties such as tensile and compressive tests have been simulated and validated against experimental data of aluminum alloy such as AA6063-T7 and AA6061, respectively. In a similar manner, the FEA simulation for a closed-die forging process has been carried out and validated against experimental result. Subsequently, a mathematical model for open-die forging having elliptical cross-section of billet has been derived with certain predefined assumptions. The potentials of FEA simulation for different materials such as aluminum alloy (AA6063), mild steel and brass, have also been investigated to justify the proposed analytical solution, which has been noticed to have less than 5% error. The intricacies involved in the simulations along with mathematical modelling have been discussed in detail in the present article.

Selective electron beam melting of an aluminum bronze: Microstructure and mechanical properties

In this work, periodic macro-cellular structures with dense struts are successfully fabricated from an aluminum brass by selective electron beam melting (SEBM). The process window for the SEBM of the Cu–Al alloy is developed. The microstructure and the mechanical properties of the Cu–Al samples are studied.

Effect of Aging Temperature on Microstructure and Mechanical Property of Aluminium Brass

Solution treated HA166-6-3-2 aluminium brass was aged at different temperatures by box-type resistance furnace. The effects of aging temperature on the microstructure and mechanical properties of HAl66-6-3-2 aluminium brass were investigated. The results show that the microstructure of aging treated HAl66-6-3-2 aluminium brass is equiaxed β phase, particle phase and dispersed precipitation phase. The precipitated phases appear and gradually increase when the aging temperature is increased. The number of precipitated phase is most at 400°C aging temperature. As the aging temperature increases continuously, the number of precipitated phase decreases and the size of precipitated phase increases, the hardness of aluminium brass presents a trend of rising first and then decreasing, the wear loss of aluminium brass presents a trend of decreasing first and then rising. When the aging temperature is 400°C, the hardness of aluminium brass reaches the maximum value of 320HV1 and the wear loss reaches the minimum value of 0.4065g. Observing the wear profile, the wear mechanism of the alloy is mainly abrasive wear under dry friction conditions.

Comment on van Casteren et al. (2018): softer metallic spheres do abrade harder enamel.

Comment on van Casteren et al. (2018): softer metallic spheres do abrade harder enamel.

The quality of water jet cutting of selected construction materials

The article presents examinations of the quality of water jet cutting process four different construction materials. The study was conducted on selected materials: aluminium alloy (AlCu4MgSi), brass (CuZn37), stainless steel (X5CrNi18-10) and non-alloy steel (S235JR). All these materials had the same thickness of 10mm. Sample geometry has been designed to be able to obtain five different surfaces and slit. During the water jet cutting process parameters were being changed to obtain five surfaces and to compare parameters. The water jet cutting process for this tests was carried out on one-head waterjet machine produced by PTV, designed for 2D and 3D cutting. Quality of all surfaces of samples was then evaluated including: surface roughness, deviation perpendicularity, bevel angle, the width of the cut and the bore. Because there are no standard describing quality tests of water jet cut surfaces, during this study standard ISO 9013:2017 for thermal cutting process was used. Basing on this standard tests of surface roughness and perpendicular deviation or slanting of cut edges were made. The other parameters were tested for information only. In this article results of this test were presented. Quality of surfaces, possibility of using this cutting method for tested construction materials were analysed. The test results have shown usability of water jet cutting process for 10mm thick aluminum alloy AlCu4MgSi, brass CuZn37, stainless steel X5CrNi18-10 and non-alloy steel S235JR. The surface quality obtained after cutting compared to construction materials is sufficient and profitable in Q3 average quality. For the better quality, of course better results, but the cost of cutting increases significantly. Therefore, the details can be cut at a lower quality, and then subjected to further mechanical processing, which is less expensive.

A Study of the Influence of Phase Composition of Cutting Inserts Made of Diamond–Tungsten Carbide Nanocomposite on the Process of Finish Turning of Aluminum Alloys and Brass

The effect of phase composition of cutting inserts made of diamond–tungsten carbide nanocomposite on cutting forces, friction coefficient in the cutting zone, and acoustic emission signal in finish turning of aluminum alloys and brass has been studied. It has been found out that the amount of 30 to 40 wt % tungsten in the initial mixture ensures sintering of a tool composite with the most favorable phase composition for turning aluminum alloys and brass.

Optical fiber sensor based on a polymer optical fiber macro-bend to study thermal expansion of metals

Thermal expansion is an important parameter for characterization of metals. As metal is heated, the molecules vibrate more violently and expand in all direction. Investigators have focused to study the thermal strain. However, the amount of expansion is difficult to measure. An attempt has been made to develop an apparatus using optical technique. The principle of this system is the transformation of length changes into changes of light intensity. The purpose of this work is to design and develop an optical fiber sensor based on a macro-bend of a polymer optical fiber. In this system, thermal expansion of metal was converted into the rolling of a needle in which placed beneath a flat bar of metal. Optical fiber sensor was attached to the ended section of a needle. As the crimp tube of the fiber sensor was moved due to thermal expansion of metal, the bend radii of optical fiber sensor was changed. As a sequence, the loss induced by the bending effect was depended on the expansion of metal that changed with temperature. In this study, we utilized optical fiber sensor to monitor and compare the thermal expansion of copper, brass and aluminum. According to our experimental results, the linear response with temperature was reported. The measured values of coefficient of thermal expansion was analyzed to be 0.45, 0.35 and 0.32 a.u./°C for aluminum bar, brass bar and copper bar, respectively. In addition, the effect of the size of the diameter of a needle on the response of bending loss was investigated.

Effect of interlayers on softening of aluminum friction stir welds

Effects of the zinc, copper and brass interlayers were studied on the microstructure evolution and mechanical properties of the wrought aluminum friction stir welds. Optical and scanning electron microscopes (SEM) as well as X-ray diffraction (XRD) analysis were used for investigation of the distribution, dissolution and reactions of the interlayers, grain structure in the stir zone and fracture surfaces. Longitudinal and transverse tensile and microhardness tests were also carried out in order to evaluate the mechanical properties of the welds. The results showed that without insertion of the interlayer, the joint efficiency (ratio of the weld strength to the aluminum base metal strength) was ~60%. While zinc and copper interlayers had no significant effect on the joint efficiency, insertion of the brass interlayer increased the joint efficiency up to ~90%. Microstructural observation indicated that brass interlayer was relatively well distributed inside the stir zone and Al2Cu and Al4Cu9 intermetallic compounds were formed due to the solid-state reactions between the aluminum matrix and brass particles during welding leading to the increase in the weld strength. In the case of the zinc interlayer, no intermetallic compound was detected inside the weld zone and zinc was dissolved in the aluminum matrix to form a solid solution. Moreover, the joint welded using copper interlayer suffered from lack of distribution of the detached copper particles. Fracture analysis after tensile test showed that insertion of the interlayers generally changed the fracture location from the advancing side towards the retreating side due to the formation of a composite structure and increase in the strength of the advancing side.

A Simple Model Linking Surface Roughness with Friction Coefficient and Manufacturing Cost

A simple theoretical model linking surface micro geometry, friction and manufacturing cost is presented. Combining a basic geometrical relationship of plastic deformation of workpiece surface asperities by a hard tool with an assumption of adhesive friction, the friction coefficient of a soft, rough surface sliding against a hard, smooth tool surface can be calculated, linking surface roughness with friction coefficient. The simple model can also link the cost related to manufacturing with a surface characterized by a given friction coefficient value. Results are presented from tests carried out to verify the simple model. Several test pieces were manufactured by turning, or grooving, an aluminum alloy and brass using different feeds, tool nose radii, and tool nose angles, achieving different surface profiles. The surfaces were characterized using a stylus profilometer and a digital microscope. The static friction coefficient was determined in terms of angle of repose using a rotary table. The experimentally determined values of the friction coefficient were compared with those predicted from feed, tool radius, and asperity angle. The tests have shown a good reproducibility, and a clear determination of the friction coefficient was possible. However, due to the low normal loads involved in this set up, the influence from the surface roughness was not clear. Further investigations are therefore proposed.

The Influence of Surface Roughness of Cutting Inserts Made of Diamond–Tungsten Carbide Composite on Cutting Forces and Machining Quality in Turning Aluminum Alloys and Brass

The paper addresses the effect of face roughness of cutting inserts made of diamond–tungsten carbide nanocomposite on cutting forces, vibration, and machined surface quality in finish turning of aluminum alloys and brass. The authors have substantiated the optimal cutting conditions to produce workpiece surfaces with the minimum roughness and waviness.

Mapping the Galvanic Corrosion of Three Metals Coupled with a Wire Beam Electrode: The Influence of Temperature and Relative Geometrical Position.

The local electrochemical properties of galvanic corrosion for three coupled metals in a desalination plant were investigated with three wire-beam electrodes as wire sensors: aluminum brass (HAl77-2), titanium (TA2), and 316L stainless steel (316L SS). These electrodes were used with artificial seawater at different temperatures. The potential and current–density distributions of the three-metal coupled system are inhomogeneous. The HAl77-2 wire anodes were corroded in the three-metal coupled system. The TA2 wires acted as cathodes and were protected; the 316L SS wires acted as secondary cathodes. The temperature and electrode arrangement have important effects on the galvanic corrosion of the three-metal coupled system. The corrosion current of the HAl77-2 increased with temperature indicating enhanced anode corrosion at higher temperature. In addition, the corrosion of HAl77-2 was more significant when the HAl77-2 wires were located in the middle of the coupled system than with the other two metal arrangement styles.

Electrochemical and Corrosion Properties of Aluminum Brass in Seawater Desalination Environments

The corrosion behavior and mechanism of aluminum brass (HAl77-2) in seawater desalination plant were investigated using electrochemical measurement, Scanning Electronic Microscope (SEM) and Energy Dispersive X-ray spectroscopy (EDX) analysis. The electrochemical results revealed that the corrosion of HAl77-2 in the desalination artificial seawater depended on chloride ion concentrations, displaying a maximum with a chloride ion concentration of 2.3 wt.%. Corrosion rate of HAl77-2 initial increased and subsequently decreased with the increasing of chloride ion concentration. Moreover, corrosion of HAl77-2 becomes more severe when temperature rises. The above results obtained by electrochemical impedance spectroscopy and potentiodynamic polarization tests were in a good agreement. The results of SEM and EDX methods showed selective localized corrosion appeared remarkably on the surface of HAl77-2.DOI: http://dx.doi.org/10.5755/j01.ms.23.4.17170

The influence of surface structure and thermal conductivity of the tube on the condensation heat transfer of R134a and R404A over single horizontal enhanced tubes

The influences of tube’s surface structure and thermal conductivity on the filmwise condensation of R134a and R404A are investigated on four single horizontal enhanced tubes with 2D and 3D finned structures. The test tubes are made of iron cupronickel and aluminum brass. The results indicate that the condensation heat transfer of R404A is more sensitive to surface structure and thermal conductivity than R134a; the 3D finned surface is more suitable than the 2D finned one to enhance the condensation heat transfer for the tubes with low thermal conductivity; the different material thermal conductivities produce different subcooling temperature distributions of the fins, and therefore provide different condensation heat transfer performances. Besides, the influencing mechanisms of the tube’s thermal conductivity on condensation heat transfer are elucidated.

Analysis of Thermal Energy Storage Tank by ANSYS and Comparison with Experimental Results to Improve its Thermal Efficiency

The discontinuous temperament of the solar power forces to consider about the energy storage. This work is to analyze the tank, amount of energy stored and its storage time. The thermal and flow analysis has been done by ANSYS with different set temperature values. The experimentation is done for various encapsulating materials with different phase change material (PCM). Findings: The results obtained from experimental work are compared with ANSYS output. The competence of the TES is calculated and further improvements are made to enhance its performance. During charging process the temperature distribution from heat transfer fluid (HTF) to PCM is maximum in copper encapsulations followed by aluminium encapsulations and brass encapsulations. The comparison shows only when the electrical power as an input source. The efficient way of captivating solar energy could be a better replacement for electrical input.