A356 Aluminum Alloy Research Articles

An Inhibitor-Loaded LDH- and MOF-Based Bilayer Hybrid System for Active Corrosion Protection of Aluminum Alloys.

A novel inhibitor-loaded bilayer hybrid system based on the LDH inner layer and MOF outer layer is designed on an aluminum alloy 2A12 surface to improve corrosion performance. The hybrid film system covers the inherent cavities and intercrystalline defects of the LDH film using the affinity between the LDH and the MOF compounds. The results demonstrate that the LDH-inhI precursor film is entirely covered by new Zn-based MOF microrods. The LDH-inhI precursor film is partially dissolved and recrystallized in favor of MOF crystal growth to strengthen the binding adhesion between LDH and MOF films. The LDH-inhI/MOF-inhII bilayer film shows significantly enhanced corrosion resistance through the synergistic action of LDH and MOF nanocontainers doped with different corrosion inhibitors (vanadates, 2,5-furandicarboxylic acid, and benzotriazoles). Due to the multiple loadings of the MOF film and the sustained-release of the LDH film, this method provides an effective approach to developing new anticorrosion systems and enhancing both the barrier ability and active corrosion protection performance of LDH-based conversion treatments.

Regression model based properties prediction of A356 aluminum alloy rheocast using cooling slope technique

The current research work involves experimental research of the Al-alloy rheocasting with enhanced microstructural and mechanical characteristics after using the Semi-Solid Metal (SSM) processing method, which is the cooling slope method. The studies here were carried out online with Central Composite Design (CCD) in order to create a non-linear regression model to represent the fabrication of A356 casting considering the Cooling Slope (CS) Technique. During the rheocasting, the angle as well as the length of the slope, along with nozzle height were taken as the input process parameters, whereas the microhardness, grain size, and sphericity of the sample were treated as the responses. The variation of such responses across the cross-section of the casting was measured at three different locations such as the center, mean, and outer radii. The non-linear regression techniques applied to the A356 sample were manufactured under two circumstances, such as ‘with’ and ‘without’ isothermal treatment. The regression models thus developed were validated by incorporating Analysis of the Variance (ANOVA). Further, the correctness of the regression representations was verified through ten experimental test samples. The percentage deviation of experimental outcomes from the model-predicted outputs was minimal. The developed mathematical models were representative of the physical process with reasonably good accuracy.

Numerical Simulation of Aluminum Foams by Space Holder Infiltration

AbstractThis study explores the simulation and analysis of the infiltration process for manufacturing A356 aluminum alloy foams using vacuum pressure. The infiltration technique, known for its versatility in liquid-state metal processing, is widely employed for metal foam production due to its ease of application. The study investigates the relationship between the geometric parameters of the preform, system pressure, and filling times, revealing a correlation. The simulation using the Flow 3D software determines the pressure and vacuum time required to achieve successful aluminum foam without filling failures. Experimental validation through infiltration casting using NaCl as a removable preform aligns with the simulated results, yielding high-quality aluminum foam samples with diverse pore sizes (0.5 mm, 1.0 mm, and 2.0 mm), uniform and interconnected pore distribution, average porosity percentages of 65%, and a relative density of 0.35. The research contributes insights into optimizing the infiltration process for aluminum foam fabrication, bridging the gap in limited literature on cellular metals.

Performance and Interfacial Microstructure of Al/Steel Joints Welded by Resistance Element Welding.

In this study, an upper sheet of an A6061 aluminum alloy and a lower sheet of Q235 steel were welded by resistance element welding with a steel rivet. The temperature field during welding was calculated using ABAQUS numerical simulation software, and the interfacial microstructure was observed. A nugget was formed between the rivet shank and the lower sheet. With increases in welding current and welding time, the tensile shear load of the joint increased first and then decreased slightly. When the welding current was 14 kA and the welding time was 300 ms, the tensile shear load of the joint reached a maximum of 7.93 kN. The smaller the distance from the position to the lower sheet along the interface between the rivet shank and upper sheet, the longer the high-temperature duration and the higher the peak temperature during welding. At the junction of the rivet shank, upper sheet, and lower sheet in the joint, the high-temperature duration was the longest, at about 392 ms, and the peak temperature was the highest, at about 1237 °C. The results show that the smaller the distance from the position to the lower sheet along the interface between the rivet shank and the upper sheet in the joint, the thicker the reaction layer generated there, and that the thickness of the reaction layer was about 2.0 μm at the junction of the rivet shank, upper sheet, and lower sheet in the joint.

Effect of Sc and Zr addition on microstructure and mechanical properties of high strength 7A52 aluminum alloy welded joints fabricated by double-wire gas metal arc welding

A new idea for improving the mechanical properties of medium-thickness 7A52 aluminum (Al) alloy welded joints was proposed. In this work, 40 mm 7A52 Al alloys were welded by double-wire gas metal arc welding (DW-GMAW) using Al-4.76Mg and Al-4.45Mg-0.70Sc-0.30Zr (wt%) alloy wires, respectively. The results showed that after adding 0.70Sc and 0.30Zr, the microstructure of weld metal (WM) transformed from dendritic grain to equiaxed grain, and the average grain size reduced from 45.04 µm to 5.55 µm (reduced by 87.7%). At the same time, the microstructure growth morphol-ogies of the molten pool changed from equiaxed grain + columnar grain + dendritic grain to equiaxed grain + fine columnar grain + equiaxed grain, while the microstructures significantly refined because micro-Al3(Sc, Zr) phases appeared in WM. The yield strength (YS), ultimate tensile strength (UTS), and elongation (El) of Al-4.76Mg welded joints were 155 MPa, 288 MPa, and 5.5%, respectively. After 0.70Sc and 0.30Zr were added, the YS and UTS increased to 226 MPa (an increase of about 45.8%) and 336 MPa (an increase of about 16.7%), respectively. The fine grain strengthening caused by the micron-Al3(Sc, Zr) phase and the precipitation strengthening caused by the nano-Al3(Sc, Zr) phase were the main reasons for the strength improvement. The findings of this study provided a theoretical basis for high efficiency and high quality for 7A52 Al alloys with medium thickness.

Strengthening of A5052 aluminum alloy by high-pressure sliding process

Strengthening of A5052 aluminum alloy by high-pressure sliding process

Experimental Investigation of Current Intensity and Feed Speed in Electrically Assisted Necking and Thickening of 5A02 Aluminum Alloy Tubes.

In order to further explore the forming limits of thin-wall tube necking and thickening, and obtain sufficient thickness of the tube in the thickening area, local electric pulse-assisted forming experiments were carried out to study the effects of current intensity and feed speed on the necking and thickening forming of thin-wall tube. The experimental results show that with the increase in current intensity, the temperature in the forming area of the tube increases, and the forming load for necking and thickening decreases. However, with the increase in feed speed, the overall forming load for necking and thickening increases in general, and the smaller feed speed is more conducive to forming. Taking into account the forming efficiency and electrode loss, the corresponding forming process window is obtained for the manufacturing of good parts. That is, during the necking stage, the current intensity shall not be less than 300 A, and the feed speed shall not exceed 10 mm/min. During the thickening stage, the current intensity should not be less than 1400 A, and the feed speed should not exceed 1 mm/min. The target part is finally formed, with an average wall thickness of 5.984 mm in the thickening zone and a thickening rate of 303.2%.

In-situ investigation on β-Fe induced tensile fracture mechanism of A356 aluminium alloy

Direct evidence for the fracture failure of aluminum alloys induced by the β-Al5FeSi phase is lacking. To ascertain the microstructural origin of the β-Al5FeSi phase-induced failure in A356 alloys, the local strain distribution of the Al5FeSi phase during deformation was quantified by combining Digital Image Correlation (DIC) strain analysis with in-situ SEM observations during tensile tests. The results indicated significant strain localization in the regions containing the β-Al5FeSi phase. TEM findings revealed that its monoclinic crystal structure is prone to high-density twinning and dislocations, which makes it difficult to undergo uniform, accommodated deformation. Moreover, the weak interfacial bonding between the β-Al5FeSi phase and the α-Al matrix, along with nanoparticles near the interface, exacerbates stress concentration.

Evaluation of Mechanical Properties and Machinability Study of Aluminium Metal Matrix Composite and Mild Steel

Abstract: Machining is one of the Core operations in most of the Manufacturing firms as it consumes most of thetime material and effort. The development of any manufacturing industry lies in a proper controlled machining environment. Hence to avoid wastage of Material and ensure in time production it is necessary to optimize the machining Process. This can be achieved through optimizing certain parameters like Speed, feed, and depth of cut etc. The Controlled machining process can be achieved through Pre simulated study or predicting the values in a computational procedure. Predictive study of parameters ensures better machinability in a specified time without much wastage of resources. In the Present Work turning operation is carried out on A356 Aluminium alloy and Mild steel in a medium duty Lathe with a HSS tool with the cutting parameters of cutting speed of 140, 310, 500m/min, feed rate of 0.35, 0.66, 1mm/rev, and cutting depth 0.5mm. Evaluation of mechanical properties is being carried out to study the influence of reinforcement particles in matrix material and Regression analysis is being carried out to predict the output value with respect to the input value

Microstructure and properties of Al–Cu–Mg alloy welded by 14 μm single-mode laser small oscillation welding

In this paper, the 14 μm single-mode laser oscillation welding technique was adopted to achieve high-quality welding of 2A12 aluminum alloy. Specifically, its influence on the microstructure and mechanical properties of the joint and the formation mechanism were investigated. The results showed that the ultra-small spot laser (28 μm) was able to achieve sequential oscillation of the molten pool with small amplitude (0.1 mm). The increased frequency caused the average grain size to decrease and the grain boundary length increased in the fusion zone. Meanwhile, the average grain orientation difference increased, and the growth orientation was more dispersed and homogeneous. While reducing weld morphology defects and refining grain microstructure, there was little influence on the penetration and width morphology of the weld. Finally, successfully prepared welds with tensile strength up to 410.4 MPa and elongation simultaneously increased to 4.065 % at 200 Hz. Furthermore, the influence of keyhole oscillation on the molten pool flow at small amplitude was explained by high-speed camera observation, which explored the mechanism of grain growth in the oscillating joints and provided new ideas for the welding of 2xx aluminum alloys.

Surface adhesion enhancement of A5052 aluminum alloy by surface texturing with a UV pulsed laser

Surface adhesion enhancement of A5052 aluminum alloy by surface texturing with a UV pulsed laser

The Impact of HIP Process and Heat Treatment on the Mechanical Behaviour of an Al–Si–Mg Alloy Component

AbstractThis study investigates the effect of hot isostatic pressing (HIPping) on the static and fatigue properties of sand-casting A356 aluminium alloys. HIPping is a method to improve the fatigue properties in aluminium cast material by reducing or eliminating the inner porosities. Investigation of the complex interaction between the microstructural features on mechanical properties before and after the HIPping process was examined using computed tomography and scanning electron microscopy (SEM). Castings generally contain pores and defects that have a detrimental impact on the fatigue properties. The HIPping process closes the porosities in all investigated samples with an increase in density. Without significant defects, the mechanical performance improved in the finer microstructure. However, a considerable variation in the results was found between the different conditions, whereas the coarser microstructure with larger porosities before HIPping showed remarkably reduced results. The high-cycle fatigue-tested samples showed reduced fatigue propagation zone in the coarser microstructure. Moreover, large cleavage areas containing bifilms in the fracture surfaces indicate that the healing process of porosities is inefficient. These porosities are closed but not healed, resulting in a detrimental effect on the static and dynamic properties.

Magnetic field treatment effects on microstructure and properties of A356 aluminium alloy

This study investigates the impact of pulsed magnetic fields (33 mT) under varying ageing temperatures (175, 185 and 195 °C) on α-Al grains, secondary phases and mechanical properties of A356 aluminium alloy. Results show that magnetic field ageing treatment can not only refines α-Al grains and promotes Si particle precipitation, but also improves the size and morphology of eutectic Si. The optimal α-Al grain refinement post-magnetic field treatment is observed at an ageing temperature of 195 °C. Meanwhile, the ultimate tensile strength and yield strength values were recorded at 345 and 283 MPa, respectively. The magnetic field ageing treatment exerts a dual influence: it accelerates atom diffusion, fostering the precipitation of reinforcing phases and simultaneously refines alloy grains, increasing the grain boundaries.

Dual-Polarized Metal Vivaldi Array Using Independent Structural Elements.

In this letter, a dual-polarized metal Vivaldi phased array antenna composed of independent structural elements is proposed, covering 6-18 GHz. By designing Vivaldi elements with a flexible and complementary structure, arrays of arbitrary shapes and scales can be constructed. The resonance caused by structural discontinuity is critically studied and eliminated to ensure good performance across the entire band. The antenna elements are fed by 50-Ohm SSMP connectors and manufactured from 2A12 aluminum alloy. An array prototype consisting of 8 × 8 dual-polarized metal has been fabricated and tested with active transmit/receive (T/R) modules to demonstrate the design concept. The array exhibits excellent beam-scanning characteristics in both the E-plane and H-plane, within the scanning range without grating lobes, which shows good agreement with the simulated results. The measured gain results are within the range of 15.2 to 24.8 dBi, and the aperture efficiencies are greater than 91% in the entire operating band. The wideband antenna technology involved in this study can effectively help increase the capacity of communication systems and meets the intentions of the Special Issue.

Ultrasonic scattering model and identification experiment of polycrystalline materials

Ultrasonic identification has an important application value for national defense, military affairs, aerospace, nuclear facilities and other high-tech fields. Ultrasonic waves can be used to identify any metal material. At present, the researches focus on algorithms for identifying the difference in ultrasonic signal among materials, but the study on the corresponding identification theory is lacking. In this work, 10 primary models of the microstructure of 2A12 aluminum alloy are established as analogies to the complex microstructures of polycrystalline metallic materials. The grains of these models are different from each other in size, separation distance, shape, arrangement directions and orders. The time-domain ultrasonic echo signals of different microstructures are calculated by making use of the finite element method. The grass-like signals between two echoes are ultrasonic backscattering signals, which are sensitive to any change of microstructure. The backscattering signals between the primary echo and the secondary echo in the ultrasonic echo time domain signals are extracted as ultrasonic fingerprints. The feature difference <i>Q</i> is defined to quantify the difference in ultrasonic fingerprint of each sample. The results show that the slight variation in microstructure will lead to difference in ultrasonic signal, and the difference caused by the variation in grain size is more distinct. And then, an ultrasonic identification algorithm is proposed, and the identification experiments are conducted on four 2A12 aluminum alloy samples with the same shape. The identification results show that the target sample can be accurately identified by using ultrasonic fingerprints and the ultrasonic fingerprints of the target sample are distinctly different from those of the other samples. The microstructure morphologies of the samples are examined by using scanning electron microscopy (SEM). The SEM results show that there are significant differences in grain size, separation distance and densification between samples although they are the same material. The features of the microstructure in the proposed ultrasonic scattering model in this work are confirmed by the actual y micromorphologies observed in the SEM images. The identification experiments and SEM results demonstrate that the established ultrasonic scattering model is effective. This work can provide a reference for theoretically studying ultrasonic identification and present an idea for developing some new identification algorithms in future.

The influence of worm gear material and lubricant on the efficiency and coefficient of friction

This paper presents the results of experimental tests of the efficiency of a single-stage worm gear. Two worm drives were used for testing, where the worms are made of improved steel 42CrMo4 and the worm gears are made of tin bronze CuSn12 and aluminium alloy A356. The values of the efficiency were determined at different values of revolutions and loads, where oils of different viscosities were used for lubrication. Determining the efficiency, the coefficient of friction of worm drives was calculated for experimental operating conditions, as well as the mass measurement of worm gears before and after testing. Based on the experimental results, depending on the operating mode and oil viscosity, the values of the efficiency of the worm drive made of the material 42CrMo4/CuSn12 are higher by 5 to 9 % compared to the worm drive 42CrMo4/A356. Higher values of the efficiency of the worm drive 42CrMo4/CuSn12 cause lower values of the coefficient of friction by 14 to 21 % as well as less wear of the worm gears.

Numerical and experimental study of residual stress in multi-pass laser welded 5A06 alloy ultra-thick plate

The laser welding technology of ultra-thick plates has been widely applied in many crucial engineering structures, where its safety and stability still suffer from the residual stress brought by the welding temperature. In this work, experimental and numerical studies are carried out to reveal the evolution and distribution of the residual stress. A 5A06 aluminum alloy plate with 30 mm thickness is used to conduct the laser welding experiment, and the short-wavelength X-ray diffractometer (SWXRD) is employed to measure the residual stress. Furthermore, a multi-pass laser welding numerical model is developed to predict the residual stress during the welding process. The simulation results of the weld pool geometry and residual stress agree well with the experimental data, which gives a good validation of the numerical model. Based on the proposed numerical model, the influence of the welding parameters, including inter-pass cooling time and welding rate are also investigated. It is discovered that the reduction of the inter-pass cooling time results in weakness effect of the temperature gradient, which hinders the generation of plastic deformation and leads to a lower residual stress value. Meanwhile, the simulation results also show that the increase in welding rate promotes the generation of thermal stress, which brings a higher residual stress value appeared in the structure.

Application of New Al-Si Welding Filler with High Concentration of Copper and Magnesium: High-Temperature Strength and Anti-Corrosion Mechanism.

Currently, the primary commercial aluminum alloy fillers used are 4043 and 5356. However, when welded with high-strength work pieces like 6061 and 7075 aluminum alloys, the strength of weld beads significantly lags behind that of the original welded material. Both 4043 and 5356 aluminum alloys cannot be strengthened through heat treatment. The strength difference between the weld bead and base material doubles after heat treatment. In this study, an Al-Si-Cu-Mg alloy (SCM) filler modified using a heat-treatable A319 aluminum alloy was employed to investigate the post-welding microstructural and mechanical properties of specimens under room- and high-temperature conditions and after prolonged exposure in a saltwater environment (3.5 wt.% NaCl). The aim was to demonstrate that commercial aluminum alloy fillers could be substituted with a high-silicon aluminum alloy boasting excellent solidification and mechanical properties. The results revealed that, after heat treatment of the weld bead, dendrites were not eliminated, but the tensile strength increased to 310 MPa, closely matching that of commercial 6061 aluminum alloy. The strength of the weld bead remained higher than 250 MPa in high-temperature (240 °C) and saltwater environments. These findings underscore the potential application of this material.

The Effect of Fe Content on the Microstructure and Tensile Properties of Friction-Stir-Welded Joints in Recycled Cast Aluminum Alloy.

The presence of the impurity element Fe significantly influences the overall performance of recycled aluminum alloy. This study aims to elucidate the impact of Fe content on the microstructure and tensile properties of friction-stir-welded (FSW) joints in recycled cast A356 aluminum alloy. Three samples with varying Fe content were prepared for FSW joints. The quality of the weld zone was meticulously assessed through macrostructure and microstructure analyses. The tensile strengths of the joints were carefully evaluated and correlated with the microhardness and microstructure of the weld zone. The research findings reveal that, among the three fabricated joints, the one with an Fe content of 0.3 wt.% demonstrates the most favorable tensile performance. This particular joint exhibits the highest tensile strength of 153 MPa, commendable yield strength of 90 MPa, and a favorable elongation of 5.7%. The mechanisms responsible for grain refinement in the weld nugget zone involve plastic deformation and dynamic recrystallization. Significantly, the disruptive effects of friction-stir action on eutectic silicon phases and rich iron phases emerge as crucial factors contributing to the enhanced performance of the weld nugget zone in the welded joint.

Microstructure and mechanical properties of longitudinal weld in 6005A aluminum alloy profile extruded by a porthole die

Porthole die extrusion experiments were carried out on 6005A aluminum alloy under the billet heating temperatures of 420–570 °C and ram speeds of 1–120 mm/min. The effects of extrusion parameters on the microstructure and mechanical properties in the longitudinal weld of profiles were investigated. It was found that the crystal orientation of longitudinal weld region showed the characteristics of gradient arrangement with different oriented grains wrapped in layers and symmetric along the welding line. The Copper{112}<111> grains are formed at the welding line under the combined effect of shear and compression, and the Goss{110}<100> grains are formed on their both sides due to dynamic recrystallization. A shear band is formed when part of metals flow through the 45° inclination angle of port bridge due to a sudden change in velocity, causing the Goss{110}<100> texture in local region to rotate to Brass{110}<112> texture. The 6005A aluminum alloy profiles mainly contain β (Mg2Si) phase, Q (Al3Mg9Si7Cu2) phase, AlCrMnSi phase and AlFeMnCrSi phase. Appropriately increasing billet heating temperature and ram speed can promote dynamic recrystallization and the dissolution of β-phase and Q-phase, thus improving the strength and hardness of the profile. However, when the billet heating temperature is too high, the strength and hardness are reduced instead due to grain coarsening. The profile extruded at billet heating temperature of 510 °C and ram speed of 120 mm/min has the best mechanical properties, with the tensile strength in 0° direction and hardness at the welding line of 179.93 MPa and 52.2 HV, respectively.