Aluminum Alloy Plates Research Articles

Evaluation on compressive properties of composite laminates with a hole reinforced by metal plate

The in-plane compressive properties of carbon fibre reinforced polymer (CFRP) laminate with a hole is investigated. In order to compare the mechanical behavior, square or round metal plate as the reinforcement is placed near the hole of composite laminate on one side asymmetrically. Quasi-static compression experiment and Speckle approach are applied to the CFRP laminates before and after aluminum alloy reinforcement. Stress concentration, strain-load relation, fiber breakage are analyzed based on experimental results. We found that the static buckling and failure load and elastic modulus of the reinforced composite laminates are larger than the unreinforced composite laminate. The compression experimental result is consistent with the digital speckle experimental result. It is also found that the reinforcement of round metal plate is close to that of square metal plate in terms of the ratio of increased failure load to increased weight. Arch beam of the unreinforced composite laminate with open hole formed when bearing compression loading is analyzed and compared to that of the aluminum alloy plate reinforced composite laminates with open hole.

Computer simulation of friction stir processing of plate from 2024 aluminum alloy

In the present work, three-dimensional finite element modeling of the friction stir processing of a 3-mm-thick 2024 aluminum alloy plates using DEFORM-3D software product has been carried out. The optimal pin length was determined based on the calculation of the distribution of effective deformation, temperature, and displacement of material points. Numerical modeling was done on pins in the form of a cylinder with a diameter of 2 mm and a length of l = 1.6, 1.8, 2.0, and 2.2 mm. Friction stir processing was carried out at a traversing rate of 2 mm/s, a tool rotation rate of 1000 rpm, and an axial force of 20 kN. The material behavior of the sheet was described using the Johnson-Cook model included in the standard DEFORM-3D library. The results showed that the most preferable under the considered processing conditions is a pin with a length of 2.0 mm because it allows one to obtain the widest and most symmetrical regions of intense heating and deformation.

SVR Prediction Algorithm for Crack Propagation of Aviation Aluminum Alloy

Aluminum alloy material is an important component material in the safe flight of aircraft. It is very important and necessary to predict the fatigue crack growth between holes of aviation aluminum alloy materials. At present, the investigation on the prediction of the cracks between two holes and multiholes is a key problem to be solved. Due to the fact that the fatigue crack growth test of aluminum alloy plate with two or three holes was carried out by the MTS fatigue testing machine, the crack length growth data under different test conditions were obtained. In this paper, support vector regression (SVR) was used to fit the crack data, and the parameters of SVR are optimized by the grid search algorithm at the same time. And then the model of SVR to predict the crack length was established. Discussion on the results shows that the prediction model is effective. Furthermore, the crack growth between three holes was predicted accurately through the model of the crack law between two holes under the same load form.

On the Correlation Between Residual Stresses and Displacements of the Polycrystalline Lattice: an Experimental Strategy

This work aims to propose a micro-indent method to evaluate the correlation between the relaxation of residual stresses and the shape changes of the polycrystalline lattice in specimens of a rolled plate of AA 6082-T6 aluminium alloy. Rolling strengthens the surface of the plate by introducing compressive residual stresses. Then, these stresses are relaxed by thermal distension. The method of micro-indents allowed measuring residual displacements with an error below ± 300 nm. The results obtained reveal that the rolling direction plays a vital role in terms of asymmetric expansion of the lattice. Furthermore, the lattice accumulates and restores elastic strain energy in the clockwise and anti-clockwise direction of rotation, alternatively. Finally, when the stress release process is finishing, the lattice adjusts the angle of rotation to approximate to the initial geometric shape.

Effect of Laser Peening on the Mechanical Properties of Aluminum Alloys Probed by Synchrotron Radiation and X-Ray Free Electron Laser

Synchrotron radiation (SR) and X-ray free electron laser (XFEL) are indispensable tools not only for the exploration of science but also for the evolution of industry. We used SR and XFEL to elucidate the mechanism and the effects of laser peening without coating (LPwC) which enhances the durability of metallic materials. X-ray diffraction (XRD) employing SR revealed that the residual stress (RS) in the top surface became compressive as the laser pulse irradiation density increased with appropriate overlapping of adjacent laser pulses. SR-based computed tomography (CT) was used to nondestructively reconstruct three-dimensional (3D) images of fatigue cracks in aluminum alloy, revealing that LPwC retarded crack propagation on the surface and inside of the sample. SR-based computed laminography (CL) was applied to friction stir welded (FSWed) aluminum alloy plates to visualize fatigue cracks propagating along the welds. The fatigue crack had complicated shape; however, it became a semi-ellipsoid once projected onto a plane perpendicular to the fatigue loading direction. Ultra-fast XRD using an XFEL was conducted to investigate the dynamic response of aluminum alloy to an impulsive pressure wave simulating the LPwC condition. The diffraction pattern changed from spotty to smooth, implying grain refinement or subgrain formation. Shifts in diffraction angles were also observed, coinciding with the pressure history of laser irradiation. The durations of the dynamic phenomena were less than 1 µs; it may be possible to use high-repetition lasers at frequencies greater than kHz to reduce LPwC processing times.

Characteristic and mechanism of nugget performance evolution with rotation speed for high-rotation-speed friction stir welded 6061 aluminum alloy

Abstract High-rotation-speed friction stir welding (HRS-FSW) can effectively reduce welding load and has a great application prospect in the field of in-situ fabrication and repair. FSW of 6061-T4 aluminum alloy plate was performed using 1000−6000 rpm rotation speeds in this study, and a detailed investigation on the characteristic and mechanism of the nugget zone (NZ) performance was conducted from aspects of experiment and simulation. The results indicate that the HRS-FSW causes the area with higher temperature and strain to transfer from the shoulder-affected zone to the pin-affected zone and the material flow to be enhanced on the retreating side of weld, leading to the improvements in the size and symmetry of the NZ. Increase of rotation speed to higher values favors the grain growth and phase dissolution and simultaneously tends to weaken the effect of plastic strain on further increase in dislocation density. The grain size is found to dominate the NZ hardness evolution with rotation speed. The evolution of NZ hardness roughly presents a Hall-Petch relationship with the grain size.

Properties of High Speed Friction Stir Welded 6063-T6 Aluminum Alloy

Friction stir welding (FSW) is as known as a revolutionary welding technology, which has come to the foreground in recent years. The low welding speed affects the efficiency of friction stir welding (FSW) and hinders the large-scale commercial application of FSW. In order to improve the welding speed and promote the application of FSW, 6063-T6 aluminum alloy plates were friction stir welded with welding speed of 3000 mm/min. The properties of welds were also tested and analyzed. The results show that the alloy plates can be successfully welded by FSW with high speed welding speed, and the tensile strength of weld can reach over 71 % that of the base material.

Effect of Special Misorientations – Crystallographic Ordered Boundaries in Recrystallization in Aluminium Alloy of Al-Si-Mg System

The deformed and recrystallized states of surface regions of hot-rolled aluminium alloy plates of Al-Si-Mg system were investigated by the method of orientation microscopy (EBSD). In the deformed state mainly shear texture components were detected. In the recrystallized structure, there was a significant dispersion of deformation texture due to an increase in the proportion of components that were located at the edges of the deformation texture. It is shown that the crystallites, which are boundary a deformed matrix with the misorientation approximately corresponding to rotation axis <552> at an angle of 52.5°, become the nuclei of recrystallization.

Properties of Friction Stir Welded 3003-H17 Aluminum Alloy at High Travel Speeds

As a new-type technology of solid state welding, friction stir welding (FSW) has a very good prospect for application. However, the welding speed is low in the practical application, and most of the time the welding speed is less than 500 mm/min, which hinders the large-scale commercial application of FSW. In this paper, 3003-H17 aluminum alloy plates of 5 mm thickness were butt welded by high speed FSW with travel speed at 1500 and 3000 mm/min and a constant tool rotation speed. The results show that 3003-H17 aluminum alloy can be successfully butt welded by high travel speed. And the UTS of weld joint decreases when the travel speed increases from 1500 mm/min to 3000 mm/min at a constant tool rotation speed of 2000 rpm and shoulder plunge depth of 0.2 mm. The joint efficiency reaches 87% at travel speed of 1500 mm/min, tool rotation speed of 2000 rpm and shoulder plunge depth of 0.2 mm.

Microstructure and mechanical performance of FSWed joint of T2 copper and AA 1061

Welding of copper and aluminium has been problematic with tradition fusion method. The friction stir welding (FSW) was employed to butt weld the T2 copper and 1061 aluminium alloy plates. The welding parameters were planned by the orthogonal experiment design method. The samples obtained in experiments were investigated in the aspects of microstructure, tensile strength, fatigue performance and micro-hardness. Sound weld with the best tensile strength and fatigue life was produced under the welding parameters of rotation speed, 1100 rpm and welding speed 50 mm min−1. The tensile strength was 193.16 MPa, 85% of the base aluminium material. Three intermetallic compounds of CuAl, Cu3Al and Cu9Al4 were detected at the copper–aluminium interface in X-ray diffraction analysis.

Experimental and numerical analysis of dynamic failure of welded aluminium alloy plates under air blast loading

ABSTRACT The paper presents experiments and finite element simulations of welded aluminium-alloy 5083-H111 plates under near-field air-blast loadings to examine their dynamic plastic deformation and failure. The material degradation takes place in the heat-affected zone affecting the failure mode of aluminium plates. Five specimens are assessed, one bare plate and four butt-welded plates. The effect of the explosive charge-plate distance and the weld seam on the structural dynamic response is evaluated. The scenario could represent an air blast action on the superstructure of aluminium-alloy vessels. The experimentally obtained deformation and failure shapes of specimens show agreement with the simulations performed by the ABAQUS finite element solver. Moreover, the finite element analysis discusses the structural deformation and rupture process of the welded aluminium alloy plates under air-blast loading and their energy transmission and absorption. The present study reveals the impact behaviour of the welded aluminium plates in contrast to the steel plates.

Experimental and numerical study on the penetration of stiffened aluminium alloy plates punched by a hemi-cylindrical indenter

ABSTRACT The present paper continues the recent works reported by Liu et al. (2020) where quasi-static indentation experiments and finite element simulations were reported to investigate the plastic behaviour and failure of four stiffened aluminium-alloy plates punched by a rigid hemispherical indenter: one bare plate, one butt-welded plate, two plates with respectively one and two flat-bar stiffeners. Here specimens with the same geometry are investigated using a rigid hemi-cylindrical indenter to examine the effect of the indenter shape on the deformation and collapse modes. The experimental comparison shows the different structural deformation and failure mechanisms of welded aluminium alloy panels. The finite element analysis discusses the importance of the modelling of welded joining details, the boundary conditions and the material degradation at welded heat-affected zones and at the same time illustrates the similarities and differences between impact analyses of aluminium and steel stiffened plates.

Synthesis of corrosion-resistant MFI-type zeolite coatings by solid-conversion secondary growth without solvent

The hydrothermal synthesis for the fabrication of zeolite coatings is the most effective route and has been extensively studied, in which a large amount of water is indispensable to ensure efficient transport of nutrition. The disposal of waste solvent and chemicals remains a big challenge in practice and an alternative route is highly desired. Herein, we present an unprecedented solid-conversion secondary growth route for the fabrication of corrosion-resistant MFI-type zeolite coatings by mixing, grinding, and heating the mixture of silica source (Na 2 SiO 3 ·9H 2 O and SiO 2 ), template (TPABr) and acidity regulator (NH 4 Cl) without addition of water. The ZSM-5 zeolite seeded aluminum alloy 1060 plates were prepared by spray-coating method where water glass as a binder between seed and substrate was used to increase the adhesion of seeds to the substrate. The continuity of the coatings was investigated by manipulating the molar composition of synthesis mixture and the optimized molar composition is 1.0Na 2 SiO 3 ·9H 2 O: 1.19SiO 2 : 0.58TPABr: 1.82NH 4 Cl. The corrosion protection performance of MFI-type zeolite coatings on aluminum alloy plates was evaluated by a direct current polarization technique. The excellent corrosion-resistant was demonstrated in severely corrosive medium including in 0.5 M H 2 SO 4 aqueous solution and 0.5 M NaCl aqueous solution, which is comparable to the performance of zeolite coatings synthesized by hydrothermal synthesis. The features are also briefly discussed, which make this route highly attractive from a good perspective. ● The synthesis of MFI-type zeolite coatings by solid-conversion secondary growth route. ● Spray-coating was introduced to produce a continuous seed layer. ● Significant effect of the composition of synthesis mixture in solid-conversion method. ● MFI-type zeolite coatings are corrosion-resistant in severely corrosive medium.

Strength and fatigue crack growth behaviours of metal inert gas AA5083-H116 welded joints under in-process vibrational treatment

Abstract Strength and fatigue properties are important design considerations for many aluminium welded structures which are operated under cyclic loadings such as ships, railway vehicles and car bodies. Over the years, various weld treatments have been developed to improve the quality of weld joints through modification of microstructure and residual stress. In the present study, in-process vibrational treatment has been applied to metal inert gas (MIG) welding of 5083-H116 aluminium alloy plates at various frequencies of 100, 300 and 500 Hz in effort to enhance strength and fatigue crack growth resistance of the weld joints. Experimental works including microstructure observation, microhardness and tensile tests, residual stress measurements and fatigue crack growth tests were performed. Results showed that in-process vibrational treatment obviously increased the ultimate tensile strength of the weld joints with the best frequency was achieved at 300 Hz. It was found that the strength of the weld at this condition was increased around 51.3 % higher than the weld in as welded condition owing to grain refinement and increasing amount of equiaxed dendritic microstructure in the weld metal region. These fine grained equiaxed dendritic structures combined with compressive residual stress induced by vibrational treatment could improve fatigue crack growth performance of the welds.

First assessment on the microstructure and mechanical properties of gtaw-gmaw hybrid welding of 6061-t6 AA

Abstract Plates of 6061-T6 aluminum alloy of 6.35 mm thick were welded by using the hybrid gas tungsten arc - gas metal arc welding process (GTAW-GMAW) and compare with the conventional gas metal arc welding (GMAW). An ER-5356 filler wire of 1.2 mm in diameter and argon of high purity as protective gas were used in both processes. The aim of the experiments was to assess the effects that yield the GTAW-GMAW welding process on the microstructure and the mechanical properties of the welded joints in the as weld and after artificial aging condition. Heat inputs were set up between ∼ 0.9 kJ/mm and ∼ 1.1 kJ/mm. Plots of the grain size and porosity ratio showed that GTAW-GMAW promoted a grain structure refinement and a reduction of porosity in weld metal. In addition, GTAW-GMAW indicate a reduction on the degradation in the heat affected zone in the as weld condition and a 40 % increase in welding speed. There was observed a major losing of magnesium in weld metal in the conventional GMAW process, this effect reflects on the final mechanical strength and microhardness of weld metal after artificial aging, as less Mg is available to get in solid solution.

Mechanical Behavior and Strengthening Mechanisms in Precipitation-Strengthened Aluminum Alloy with Gradient Structure Induced by Sliding Friction Treatment

The flat surfaces of a 7075 aluminum (Al) alloy plate were processed by sliding friction treatment (SFT), which is a technique for surface nanocrystallization of metals and alloys. The aim of this study was to investigate the microstructural evolution, mechanical behavior and strengthening mechanisms in this SFTed precipitation-strengthened Al alloy. The SFT resulted in a gradient structure (GS) with an effective depth of ~ 800 µm, and a nanostructured layer was formed within a depth of ~ 30 µm from the surface. Increasing boundary spacing and decreasing misorientation angle between boundaries were found with increasing depth from the surface, which was accompanied by a decrease in hardness from ~ 2436 MPa in the topmost surface layer to ~ 1568 MPa in the undeformed coarse grain (CG) matrix. Moreover, the GS revealed a prominent precipitate redistribution induced by the SFT. The GS revealed higher strength and especially exhibited a higher work-hardening rate at low strain (e < 0.026) than the CG, attributed to a novel coupling of dislocations, boundaries and precipitates. Grain boundary strengthening, dislocation strengthening, precipitation strengthening and synergetic strengthening in the GS were quantitatively evaluated based on sufficient discussion.

Effect of Curing Cycle on Fatigue Life of Cracked AA7075-T6 Aircraft Sheet Repaired with a Boron/Epoxy Composite Patch

Fatigue failure cracking under fluctuating stressing has been a major concern of engineering for many years. Fatigue failures have become more common and thereby significantly influencing engineering design as sources of vibration and dynamic loading of components have increased. The repairs of damaged metallic structures using bonded composite patch have been proved as an economical method to increase the fatigue life of damaged structures. This paper deals with an experimental study on the fatigue life of AA7075-T6 aluminium alloy plates reinforced with single-sided boron/epoxy patches. The study focuses on the effect of different curing cycles on the fatigue life of reinforced/repaired structure. Bonds were tested with four different curing cycles. Distortion behaviour of bonded repair is studied. The influence of the curing cycle conditions on fatigue life is presented. Also, the repair patch effectiveness on the stress state at the crack tip in increasing the fatigue life of the unrepaired structure is shown. The obtained results show that repair of the cracked plate can be done effectively by using bonded composite patches. It is shown to decrease the crack growth rate to enhance the fatigue life of the structure by 70%. Elevated curing temperatures enhance the adhesion between the metal surface and the composite patch and overall durability. However, elevated cure temperature may result in distortion with bending curvature. The optimum combination of temperature and duration for the curing cycle is of importance to reduce the distortion.

Characterizing the damage behavior of thin sheets for fuselage based on in situ corrosion fatigue test and digital image correlation technique

The effect of salt spray and salt solution on the fatigue properties of 2024-T3 aluminum alloy plate used for aircraft fuselage structure have been investigated by combining Digital Image Correlation (DIC) technology with in-situ corrosion fatigue test. For this purpose, an in-situ corrosion fatigue platform was designed for gas and liquid phases. Fatigue experimental investigation was carried out in salt spray and salt solution environments respectively, the crack propagation process was monitored by the DIC technology and the influences of NaCl concentration on fatigue life and crack growth rate were analyzed under the two kinds of corrosive environments. Moreover, the failure mechanism is discussed based on the micro-morphology of fracture and the composition of corrosion products. Experimental results demonstrated that for the corrosion fatigue in salt spray environment, there is a competition between the hydrogen embrittlement and the crack tip closure effect caused by corrosion products, which results in fatigue life decreasing with the increase of NaCl concentration first and then increasing. The fatigue life (with 3.50 wt.% NaCl salt spray) is the lowest, which is 82.9% of that in air, while the fatigue life (with 5.00 wt.% NaCl salt spray) is 112.6% of that in air. But for the corrosion fatigue in the NaCl salt solution environment, there is no obvious crack tip closure effect. In the 5.00 wt.% NaCl salt solution environment, fatigue life is 74.2% of that in air. The microfractures and strain nephogram of specimens revealed the stress concentration caused by corrosion pits, which might be the main factor for the decrease of fatigue life.

Study on Ultimate Compressive Strength of Aluminium-Alloy Plates and Stiffened Panels

This work reviews the ultimate compressive strength of aluminium plates and stiffened panels. The effect of boundary condition, initial imperfection, welding-induced residual stress and heat-affected zone are discussed. As the effect of manufacturing technology lacks in the literature, this effect is analysed employing the finite element method, considering the technology of welding and integrated extrusion. The numerical analyses have shown that the ultimate strength of the integrated extruded stiffened panel is relatively higher than the one of the traditional welded panel.

Microstructure and Mechanical Strength Predictive Modeling in Al 5052-Trapezoidal Grooved SS 304 Explosive Cladding

Aluminum alloy plates were explosively cladded to stainless steel plates with trapezoidal grooves on the mating surface. The process parameters viz, loading ratio, standoff distance and flyer plate thickness were varied based on the Taguchi analogy. The variation in the process parameters alters the kinetic energy dissipation and the deformation work performed at the interface, and dictates the interfacial wave amplitude and the mechanical strength of the dissimilar explosive clad. The optimum level of process parameters for attaining higher tensile and shear strength is computed by signal-to-noise ratio. Further, a mathematical model is developed for calculating tensile and shear strength of the clad, based on the regression analysis using statistical software Minitab-16, and the level of fit is determined by analysis of variance.