Aluminum Alloy Plates Research Articles

Study on the key parameters of ice particle air jet ejector structure

Existing ice particle jet surface treatment technology is prone to ice particle adhesion during application, significantly affecting surface treatment efficiency. Based on the basic structure of the jet pump, the ice particle air jet surface treatment technology is proposed for the instant preparation and utilization of ice particles, solving the problem of ice particle adhesion and clogging. To achieve efficient utilization of ice particles and high-speed jetting, an integrated jet structure for ice particle ejection and acceleration was developed. The influence of the working nozzle position (Ld), expansion ratio (n), and acceleration nozzle diameter ratio (Dn) length-to-diameter ratio (Ln) on the ice particle ejection and acceleration was systematically studied. The structural parameters of the ejector were determined using the impact kinetic energy of ice particles as the comprehensive evaluation index, and the surface treatment test was conducted to verify the results. The study shows that under 2 MPa air pressure, the ejector nozzle parameters of n = 1.5, Dn = 4.0, Ld = 4, and Ln = 0 mm can effectively eject and accelerate the ice particles. The aluminum alloy plate depainting test obtained a larger paint removal radius and resulted in a smoother aluminum alloy plate surface, reducing the surface roughness from 3.194 ± 0.489 μm to 1.156 ± 0.136 μm. The immediate preparation and utilization of ice particles solved the problems of adhesion and storage in the engineering application of ice particle air jet technology, providing a feasible technical method in the field of material surface treatment.

Study on microstructure and mechanical properties of 5052 aluminum alloy MIG welded joint for high-speed train

In this paper, the MIG welding process is utilized to weld a 3 mm thick 5052 aluminum alloy plate by using ER5356 welding wire as filler. The effects of different welding speeds on the microstructure and mechanical properties of the weld are systematically studied utilizing a metallographic microscope, x-ray diffractometer, scanning electron microscope, room temperature tensile, and microhardness. It was found that there were pore defects in the samples at lower or higher welding speeds, and there was no penetration at the maximum welding speed. When the welding speed is 650 mm min−1, the weld is well-formed, the surface is flat without pores, the fish scale is evenly distributed, and the weld shows good penetration. The intermetallic compounds of all the welds are mainly composed of α(Al), Mg2Si, Al3Fe, and Al3Mg2. The mechanical properties of the samples show that the hardness of the weld reaches the maximum value of 56.7HV at this welding speed, and the tensile strength and elongation are 210 MPa and 14.3%, respectively. The fracture is located at the junction of the base metal and the heat-affected zone, and the fracture type showed typical ductile fracture.

Early detection of fatigue-induced material changes by modulation of ultrasound in dynamically loaded structures

In this work, an ultrasonic approach for early detection of fatigue-induced material changes in an aluminium alloy plate under dynamic loading is developed and validated. Material degradation followed by the emergence and growth of a crack was created by a fatigue machine while monitoring the modulation of sinusoidal ultrasonic wave packets sent along the plate around high- and low-load instants in the fatigue cycle. The determined wave parameters and the difference between their high- and low-load values were found to be very sensitive not only to the emergence of the crack but also to the plastic deformation, which, according to digital image correlation monitoring, preceded the crack formation and changed the effective elastic modulus felt by A0 and S0 Lamb mode contributions to the wave packets. Experimental analysis and simulations showed that the high sensitivity to microstructural changes was resulting from their substantial effect on the propagation velocity of the arriving A0 and S0 wave packet contributions, which in turn had a strong influence on their interference.

Investigating the effect of stress ratio on fatigue crack growth rate behaviour in friction stir welded AA7075-T651 aluminium alloy plates

This study examines the characteristics of Fatigue Crack Growth Rate (FCGR) in AA 7075-T651 Friction Stir Welded (FSW) joints with a thickness of 16 mm. Compact tension (CT) specimens from both the base and the FSW joints were utilized to assess FCGR under various stress ratios (0.2 to 0.5). Additionally, the study involved analyzing the transverse tensile characteristics of both the based and the welded joints. The microstructures of the welds were inspected using optical and transmission electron microscopes. Findings indicate that the FSWjoint critical stress intensity factor range (ΔKcr)is lower than the unwelded base, that can be related to precipitates dissolving in the weld zone when the friction stir welding process. Consequently, in contrast to the unwelded base, the fatigue life of AA 7075-T651 aluminium alloy FSW joints is significantly reduced. A scanning electron microscope carried out microstructural analyses of the fracture surfaces of the FSW and base under various stress ratioconditions. The results showed that, in contrast to the parent material, the FSW joint has ultra-fine grains resulting in intergranular cracks in the propagation zone.

Comprehensive Analysis of Laser Peening Forming Effects on 5083 Aluminum Alloy.

In order to investigate the laws of the laser peening forming process and the effects of laser peening on the surface quality and tensile properties of 5083 aluminum alloy, experiments were conducted utilizing various laser peening paths, energies, and plate thicknesses. Subsequently, laser peening forming experiments were performed on S-shaped and different shapes of aluminum alloy substrates. The impact of different laser peening durations on surface morphology and tensile properties was then analyzed. Results indicated that the largest bending deformation perpendicular to the laser peening path reached 12.5 mm. In cases where the laser peening path was inclined relative to the horizontal direction, torsional deformations were observed in the aluminum alloy plate. For laser energy levels of 5 J, 6 J, and 7 J, deformation amounts were 3.8 mm, 4.9 mm, and 5.4 mm, respectively. Plates with thicknesses of 4 mm exhibited convex deformation, while those with 2 mm thickness showed concave deformation. Furthermore, following one and two laser peening cycles, the residual stresses in the alloy plates were -80 MPa and -107 MPa, the surface hardness increased by 16 HV and 31 HV, the roughness increased by 2.495 μm and 3.615 μm, and the tensile strength increased by 9.5 MPa and 18.5 MPa, respectively.

Theoretical and experimental investigation into detection of early-stage propagation of double cracks with distributed fiber optic sensor

A strain transfer model is developed to describe the transfer of crack opening displacement (COD) of double cracks in a structural substrate to the distributed fiber optic sensor (DFOS). Global and local coordinate systems are set up to aid in the deduction of the transfer of CODs of the double cracks to the DFOS. The analytical model of strain transfer is first derived in the local coordinate system and then is transformed into the global coordinate system. Analytical results show that the DFOS fiber strain induced by CODs of the double cracks in the structural substrate is affected by both the spacing and the CODs of the double cracks, and the strain peak is suppressed as the crack spacing is less than the characteristic length which is defined as the range of influence of the COD of the individual crack. The influences of the material properties of the DFOS, the fiber coating, the bonding adhesive, and the DFOS-fiber coating interfacial stiffness are discussed. The developed model is also experimentally validated by monitoring CODs of double cracks in aluminum alloy plates with optical frequency domain reflectometer (OFDR) DFOSs. Experimental results show that the strain distribution measured by the OFDR DFOSs agree well with the analytical results of the developed model. The limitations of the developed model and future work anticipated are then discussed.

Research on adaptive penetration characteristics of space harpoon based on aluminum honeycomb buffer

To address the issues of high impact and limited adaptability in capturing space debris with space harpoons, a novel harpoon capture device based on aluminum honeycomb buffering was proposed. The issue of excessive impact force for harpoons could be effectively addressed by the excellent energy-absorbing characteristics of aluminum honeycomb. A simulation model was established to analyze the penetration of space harpoons into aluminum alloy target plates using Johnson-Cook’s dynamic constitutive model and fracture failure criteria. Ground experiments were conducted to validate the correctness of the simulation model. The impact of aluminum honeycomb was investigated by analyzing the simulation results of harpoons with and without aluminum honeycomb. With the introduction of aluminum honeycomb as a buffering component, the rebound velocity of the harpoon decreased by 76.2 %, and the impact force reduced by 78.6 %. Then the model was used to study the influence of different launching angles and different targets on the penetration characteristics of the space harpoon. The research findings indicate that space harpoons could successfully penetrate and capture aluminum alloy targets at a launch velocity of 53.1 m/s to 58.5 m/s, as determined through ground experiments and simulation analysis. The error in the crushing height of the aluminum honeycomb was found to be 2.19 %, while the error in the harpoon penetration depth was 9.02 %. Moreover, within a launch angle error of 10°, space harpoons also demonstrate the capability for adaptive capture of both aluminum alloy plates and aluminum honeycomb sandwich panels, with average correction capabilities of 92.5 % and 95.5 %. In conclusion, the analysis of the adaptive penetration characteristics of space harpoons provides a solid theoretical foundation and technical support for the design of harpoon capture systems.

Fabrication of magnetic pulse welding sheets of aluminum alloy and GA steel plates subjected to film removal treatment and their welding property

Fabrication of magnetic pulse welding sheets of aluminum alloy and GA steel plates subjected to film removal treatment and their welding property

Optimization of microstructure and properties of thick Al alloy welded joints for one-step formation by keyhole welding

To solve the problem of insufficient strength of thick aluminum alloy welded joints, this study introduces a pioneering technique known as variable-polarity plasma arc keyhole-tungsten inert gas cover hybrid welding (VPPA keyhole-TIG covering welding), which is designed for welding large-thickness aluminum alloys without any weld groove. Using 13-mm-thick 2319 aluminum alloy plates as experimental materials, plasma arc butt welding experiments were conducted by varying the plasma gas flow rate and application of cover welding. The research findings underscored that the use of cover welding, coupled with an increase in the plasma gas flow rate, markedly improved the overall performance of the weld. An average tensile strength of 299.0±4.0 MPa and an elongation rate of 4.5±0.3 % were achieved for the welded joint. A microscopic analysis revealed that the heightened plasma gas flow rate did not precipitate the θ' phase but instead resulted in undesired grain size enlargement, leading to reduced joint hardness. The secondary thermal cycle effect of covering welding played a pivotal role in facilitating the nucleation of needle-like θ' strengthening phases within the matrix, ranging in size from 50 to 150 nm. This phenomenon has emerged as a principal factor contributing to the substantial enhancement of the mechanical properties of welded joints.

Structure and properties of the hot pressing molded anodized aluminum alloy/polyformaldehyde hybrids

The metal-plastic hybrid is one of the important solutions for lightweight and high-strength composite. The anodized aluminum alloy（AAA）/polyformaldehyde（POM） hybrids with excellent mechanical properties were processed by the hot pressing technology. The surface of the aluminum alloy plate was firstly pretreated with phosphoric acid and oxalic acid anodizing, resulting in a large number of micro-nano scale pores on the surface. These pores were well embedded with plastic melt during hot pressing to form micro-nano mechanical interlocking structures and the Al–O–C chemical bond at the interface is generated, thus ensuring good bonding strength at the metal and plastic interface. The maximum tensile-shear strength of the metal-plastic hybrid was 30.65 MPa, meanwhile, the metal-plastic interface failure presented mainly a mixed failure mode, including resin removal from the metal surface and plastic tearing from the plastic surface. At the same time, the salt spray test, thermal shock test, and variable temperature test were adopted to investigate the application performance of the metal-plastic hybrid. The Al/POM hybrids were able to maintain their mechanical strength above 20 MPa for 28 days in a salt spray environment, 14 times in a thermal shock cycle, and at high temperatures. The high mechanical strength of hybrid has good potential for automotive applications.

Wire-feeding friction stir welding for large-gap width tolerances

A novel method, named wire-feeding friction stir welding, was proposed for welding large-gap-width joints. Continuous wire feeding and welding systems were designed. AA6082-T6 aluminium alloy plates with a gap width of 2 mm were welded using Al–Si alloy wires as the filler materials. Sound joints were obtained even if the gap width reached over 2/3 thickness of the base materials. Fine microstructures were obtained via dynamic recrystallisation induced by severe plastic deformation. The ultimate tensile strength of the joints reached 253.4 ± 1.3 MPa. The adaptability to working conditions of friction stir welding was improved for long welds of high-speed railway, ship and aircraft.

Effect of Welding Parameters on Lap Shear Force of Similar and Dissimilar Friction Stir Spot Welded Aluminium Alloys

Friction stir spot welding (FSSW) is a solid-state single-point welding technique that uses a rotating tool consisting of a shoulder and a pin for joining nonferrous metals and alloys. FSSW produces a keyhole at the welding point, which decreases the mechanical strength of the joints. This study investigates the influences of tool rotational speed (1000, 1250, and 1500 rpm) and dwell time (5, 10, and 15 s) on the shear fracture load of the FSSW joints. Two different grades of aluminium alloy plates, i.e., AA6061 and AA7075 were used to produce similar (7075-7075 and 6061-6061) and dissimilar (6061-7075) alloy joints. The plates with a thickness of 3 mm were folded above each other before a rotating tool pin was plunged through the thickness of the top plate to obtain an FSSW lap joint. It was found that tool rotational speed and dwell time induced a considerable impact on the microstructure, and shear strength. The results indicated that the grain size of microstructure in similar and dissimilar joints was affected by the rotational speed and dwell time. The grain size of the microstructure increased as rotational speed and dwell time increased. The results also showed that a tool rotational speed of 1250 rpm and dwell time of 10 s gave the highest shear fracture load for 7075-7075 similar and 6061-7075 dissimilar joints. However, for 6061-6061 similar joints, the highest mechanical strength was obtained at 1250 rpm and 10 s.

Experimentally validated numerical prediction of laser welding induced distortions of Al alloy parts for railcar body by inherent strain method combined with thermo-elastic-plastic FE model

A laser welding with wire filler feeding was developed to replace traditional arc welding process for joining aluminium alloy railcar body components. A three-dimensional (3D) thermo-elastic-plastic finite element (FE) model was applied to compute the plastic strains of weld zone in a downsized aluminium alloy plate with butt-joint, T-joint and fillet-joint configurations, respectively, combined with corresponding experimental validations. The achieved plastic strains at the weld zone were then input as inherent strain loadings into elastic structural FE model of fully sized aluminium alloy railcar body components to predict the welding induced distortion with the experimentally measured out-of-plane distortions. The experimentally validated FE model was then further applied for optimizing the inverse pre-deformation of plates to counteract the welding induced deformation, finally to mitigate the welding distortion issues.

Predicting the temperature distribution in friction stir welding thick 2219 aluminum alloy plate based on LSSVM

Predicting the temperature distribution in friction stir welding thick 2219 aluminum alloy plate based on LSSVM

Ultrasonic Non-Destructive Detection Method for Residual Stress in Rotary Forging Aluminum Alloy Plates.

Aluminum alloy plates are widely used to manufacture large-scale integral structure parts in the field of aerospace. During the forming and processing of aluminum alloy plates, different degrees of residual stress are inevitably produced. Fast and accurate detection of residual stress is very essential to ensuring the quality of these plates. In this work, the longitudinal critically refracted (LCR) wave detection method based on a one-transmitter and double-receiver (OTDR) transducer and the finite element simulation were employed to obtain the residual stress. Aluminum alloy plates with different deformation amounts were fabricated by rotary forging to obtain different residual stress states. Results reveal that the plate formed by rotary forging is in a stress state of central tension and edge compression. As the deformation increases from 20% to 60%, the peak residual tensile stress increases from 156 MPa to 262 MPa, and there is no significant difference in the peak compressive stress. When the deformation reaches 60%, the difference in the residual stresses at different depths is less than 13%, which indicates that the plastic deformation zone basically penetrates the entire longitudinal cross-section of the plate. The maximum deviation between measurement and FE is 61 MPa, which means the experimental data are in good agreement with the FE results.

Component Effects in Binary Droplet Impact Behaviors on the Heated Plate: Comparison Study of Ethanol/Propanol and Ethanol/Water Droplets and Observation of Novel Bubble Shrinkage Phenomenon

This work aims to investigate the effect of liquid physical properties on the behavior of binary droplets impact on the heated smooth aluminum alloy plate with a high-speed imaging system. Two groups of mixed solutions with similar boiling point differences are selected as the working liquid, in which the low-boiling-point components are both ethanol and the high-boiling point components are propanol and water, respectively. Compared to the ethanol/propanol binary droplets, the experimental results show that the ethanol/water binary droplets have diverse impact phenomena and significantly broad transition boiling regimes, as well as the reduced droplet residence time and increased Leidenfrost temperature point. With the decreasing ethanol content in ethanol/water binary droplets, these effects become more prominent. For secondary atomization, the ethanol/water binary droplet undergoes parent droplet breakup into fragment droplets with larger diameters (Ds > 0.3 mm). Both binary droplets produce satellite droplets with small diameters (Ds < 0.3 mm) by puffing and ejection. In terms of the ethanol/propanol binary droplet impact, the probability of puffing is higher and the satellite droplet diameters are small. In the ethanol/water binary droplet impact, the probability of ejection is higher and the satellite droplet diameter distribution is wider. When an ethanol/water binary droplet of 25 vol.% ethanol content impacts the heated wall at Ts = 120 °C, a novel large bubble shrinkage phenomenon occurs at the late stage of droplet evaporation. This phenomenon is proposed to be relevant to the increasing surface tension and saturation temperature with decreasing ethanol content, as well as the decreasing ambient temperature above the top surface of the bubble.

Evaluating the impact resistance of double-layered aluminum alloy plates with diverse shapes against blunt rigid projectiles

Evaluating the impact resistance of double-layered aluminum alloy plates with diverse shapes against blunt rigid projectiles

Ballistic resistance of 7XXX laminate aluminum alloy plates and base alloys subjected to different projectiles

The ballistic impact of two 7XXX aluminum alloys, 7A52-T6 and 7A62-T6, as well as their combination in a 7B52 laminate plate, was simulated and experimentally tested. Three types of projectiles were utilized hard ogival nosed, hard blunt nosed, and 304 steel core projectiles to investigate the ballistic resistance and failure mechanisms of the aluminum alloy targets. Additionally, an existing modified Gurson-Tvergaard-Needleman (GTN) model incorporating shear, void growth, and spalling failure mechanisms, was employed to simulate the ballistic impact process, utilized to analyze energy dissipation during impact. The results reveal that the 7A52 alloy only experiences ductile hole expansion failure, whereas the 7A62 high-strength aluminum alloy undergoes spalling and fragmentation subsequent to penetration, leading to potential impact hazards. Due to its backing layer being the highly ductile 7A52 alloy, the laminate plate will not produce fragments after penetration. The improved GTN model provided better predictions of the impact failure modes of the aluminum alloys. Concerning impact performance, when subjected to hard ogival projectiles, the laminate alloy did not enhance material impact resistance. However, when impacted by blunt-nosed projectiles, the laminate alloy exhibited a 27 % improvement over the 7A52 plate and an 11.9 % increase over the 7A62 plate. Furthermore, when impacted by 304 steel core ogival projectiles, the laminate alloy demonstrated over a 41.3 % improvement compared to the 7A52 plate and over a 15.5 % increase compared to the 7A62 plate. The laminate plate's high ballistic performance was attributed to the increased plastic deformation energy after spalling failure, while ensuring high energy absorption during ductile hole expansion penetration.

Effect of Operating Speed on Turbocharger Compressor Blade Wear

In harsh environments, turbochargers require continuous adjustment of the rotating speed, which can lead to differences in erosive wear on the blades compared to erosive wear under constant speed conditions. In this study, the erosion model expression for an aluminum alloy plate with a fitted Ks value of 20 μm under the erosion of 160 μm SiO2 particles is obtained through erosive wear experiments. Taking a turbocharger compressor as the research object, the influence of four commonly used working speeds on blade wear is analyzed. The results show that when the speed increases from 70,000 rpm to 130,000 rpm, the maximum wear rate concentration values for the main and splitter blades increase by approximately 590% and 310%, respectively.

Analysis of bullet impact test on aluminum alloy plates at varying thickness and velocities

Analysis of bullet impact test on aluminum alloy plates at varying thickness and velocities