AA 5083-H111 Research Articles

Thermal and mechanical characterisation of friction stir welded dissimilar aluminium alloys

The influence of thermal properties on the friction stir welded (FSW) dissimilar aluminium alloys at different tool rotational speeds and tool pin profiles was studied. AA 5083 H111 and AA 6082 T6 of 6 mm aluminium alloy plates are welded by varying the process parameters. The influence of heat generation and heat transfer in the joint efficiency of the weldments are characterised. Heat flow and heat flux for various tool rotation speeds generated between the tool shoulder and workpiece are calculated and analysed. The rate of heat distribution during welding is evaluated by calculating the thermal diffusivity of AA5083 H111 and AA6082 T6. Microhardness test helps to comprehend the influence of the parameters over the mechanical property of the weldments. The results revealed that the thermal characterisation clearly illustrates that an increase in tool rotation speed directly amplifies the heat flow and heat flux in weldments. However, AA 5083 H111 and AA 6082 T6 for varying temperature and reveals that 580°C possessed higher thermal conductivity for AA 6082 T6 (260 W/m°C) and AA 5083 5083 H111 (160 W/m°C), thermal conductivity for AA 6082 T6 (1260 J/Kg°C) and AA 50835083 H111 (1225 J/Kg°C) and thermal Diffusivity was 5.2029 × 10−5 (m2/s) for AA 5083 H111 and 7.61819 × 10−5 (m2/s) for AA 6082 T6.

Corrosion Behavior of Aluminum Alloys in Different Alkaline Environments: Effect of Alloying Elements and Anodization Treatments

Aluminum alloys are extensively used to manufacture mechanical components. However, when exposed to alkaline environments, like lubricants, refrigerants, or detergents, they can be corroded, reducing their durability. For this reason, the aim of this study is to investigate the influence of aggressive alkaline solutions (i.e., pH and presence of chlorides) on the corrosion resistance of three aluminum alloys (AA 5083-H111, AA 6082-T6, and AA 7075-T6) with and without anodizing treatments. Open circuit potential (EOCP) and anodic polarization measurements were carried out and typical corrosion parameters such as corrosion current density (icor) and corrosion rate (CR) were determined. Morphology of the corrosion attack and samples microstructure were investigated by scanning electron microscope. Results show that corrosion behavior of the three investigated alloys is influenced by (i) the aggressiveness of the testing environments; (ii) the thickness of the anodizing treatment; (iii) the alloy chemical composition; (iv) the distribution of intermetallic phases in the aluminum matrix. Moreover, three galvanic series have been built also testing other metallic alloys commonly used in mechanical applications, i.e., carbon steel (C40), stainless-steel (AISI 304), and Cu-based alloys (Cu-Ni alloy and CW 617 N, respectively). Results clearly indicate that galvanic series play a fundamental role when it is necessary to select an alloy for a specific environment, highlighting the thermodynamic conditions for corrosion occurrence. On the other hand, kinetic measurements and microstructural studies carried out on the three aluminum alloys stress the importance of the surface treatments and relevant thickness as well as the effect of metal exposure. Future work will involve the study of other surface treatments on aluminum alloys and the evaluation of their corrosion behavior in acidic environments.

Optimization of process parameters in friction stir welding of dissimilar aluminum alloys (AA6061–T6 and AA5052–H32)

Optimization of process parameters in friction stir welding of dissimilar aluminum alloys (AA6061–T6 and AA5052–H32)

Implementation of Fracture and Flow Stress Models for AA5052-H32 Sheet Deformed Through Shock Tube–Based Forming Technique

Abstract Selection of flow stress models and fracture models to model sheet deformation at high strain rates is of great concern. The same is attempted in the present work during shock tube impact forming of 1-mm-thick AA 5052-H32 sheet using a rigid nylon striker. Lab scale experiments and finite element simulations using DEFORM 3D are conducted for the purpose. Johnson–Cook flow stress model and Modified Johnson–Cook flow stress model along with fracture models like normalized Cockcroft and Latham model, Rice and Tracey model, Oyane model, and McClintock model are tested for their accuracy and consistency. The fracture strain and fracture pattern evaluation suggest that the modified Johnson–Cook flow stress model and Rice and Tracey fracture model are suitable for fracture prediction, and it is better to use these together for fracture evaluation. An alternate method of evaluating rate-dependent tensile properties of sheet at higher strain rates is proposed and delivered acceptable fracture prediction results. Finite element simulations using Hollomon power law predict a strain rate of 1925/s at a striker velocity of 49.79 m/s, which is in the range of values in literature for explosive forming. Systematic shock tube forming experiments for calibrating the fracture models are acceptable.

A study on the mechanical, electrochemical and microstructural behaviour of AA5052 welded sheets

Aluminium 5xxx series alloys are most robust non-heat-treatable aluminium alloy and mostly used in aerospace, automotive components and body structures due to its high corrosion resistance, good strength and light weight. The alloy used in this work is AA5052 H32 (cold rolled) of 1 mm thickness to highlight the precedence of friction stir welding (FSW) over fusion welding technique, i.e., Tungsten Inert Gas welding (TIG). In TIG, the selected input variable parameter is welding speed and the other parameters such as inert gas flow rate, welding speed and frequency were kept constant during the study. In FSW, the selected input variable is feed rate, and the parameters such as plunge depth and tool rotational speed were kept constant after conducting several trials. Mechanical, Electrochemical, and Microstructural behaviour of both welded samples were studied. It was found that Friction stir welding samples has better mechanical properties than TIG welding due to solidification cracks and porosity defects. The tensile and microhardness results of FSW were 7.3 % and 5.4% more than TIG due to solidification cracks, porosity defects and intermetallics formed. The corrosion behaviour of both FSW and TIG were less than the base material due to precipitate dissolution. In the present study a comparative study of FSW and TIG is studied and reported.

Investigation of mechanical, metallurgical and corrosion characteristics of friction stir welded dissimilar AA 5052-H32 and AA 6061-T6 joints

ABSTRACT Welding is used for fabricating various components to increase the application of aluminum alloys. When compared to fusion welding, friction stir welding (FSW) is used to join non-ferrous and ferrous with similar and dissimilar materials with fewer defects. In the present work, FSW was carried out between 5 mm thick plates of solid solution-strengthened AA 5052-H32 and precipitate-strengthened AA 6061-T6 alloys. The plates were welded at tool rotational speeds (TRS) of 800, 950, and 1100 rpm. Furthermore, a salt spray test was conducted on both base metals and FSW joints. The scanning electron microscope was accustomed to examining the microstructure of the base metals and different zones. Mechanical characterization was performed to determine the welds’ strength and hardness. The phase examination was then performed on the weld nugget zone using X-Ray Diffraction (XRD). To determine the mode of failure, the tensile fracture surfaces of the welded samples were inspected. The study found that the joint prepared at 950 rpm yielded maximum tensile strength of 174.3 MPa, % elongation of 13.8% and a higher hardness of 72 HV related to other joints. The corrosion test results exposed an enhancement in corrosion resistance of maximum tensile strength obtained from the welded joint

Material flow and mechanical properties of friction stir welded AA 5052-H32 and AA6061-T6 alloys with Sc interlayer

Abstract Friction stir welding (FSW) is superior to fusion welding for joining incompatible alloys. In FSW Al/Mg alloys, developing IMCs like Al3Mg2 and Al12Mg17 is almost predictable and undesirable. Continuous IMCs produce a simple fracture propagation path, increasing brittleness and reducing weld strength. AA5052-H32 and AA6061-T6 were joined with a scandium (Sc) strip in the current study to improve material flow and reduce brittleness. Interlayer added on these alloys are the military-grade aluminium alloys used in the production of ship hull constructions and armoured helicopters. During FSW, a threaded cylinder tool with a rotating speed (TRS) of 1600–2000 rpm, welding speed (WS) of 60–80 mm/min and tool pin depth (TPD) of 0.1–0.4 mm were used to create the weld joints. To improve the strength of the above material combination during FSW, a 2 mm thickness Sc interlayer was added. The mechanical and metallurgical characteristics of the weld joints were studied. The maximum ultimate tensile strength value obtained from the cylinder-threaded tool pin profile with 0.1 mm TPD presented 237.63 MPa. Experimental interpretations were employed using response surface methodology-box Behnken design (RSM- BBD). FSW variables’ influence was investigated using the analysis of variance (ANOVA) technique.

Influence of Plasma Treatment on Surface Characteristics of Aluminum Alloy Sheets and Bonding Performance of Glass Fiber-Reinforced Thermoplastic/Al Composites.

This study focuses on modifying the surface of an AA 5052-H32 aluminum alloy using plasma treatment. Discharge power, exposure time, and working gas were adjusted as process parameters to improve the adhesion between the aluminum alloy and glass fiber-reinforced thermoplastic (GFRTP) polycarbonate composite. The surface composition and morphology of the aluminum alloy sheet were analyzed by X-ray photoelectron spectroscopy and scanning electron microscopy, and surface roughness and wettability were evaluated using a surface roughness-measuring instrument and contact angle goniometry, respectively. The bonding performance of GFRTP/aluminum alloy was also assessed. The surface of the aluminum alloy was subjected to chemical treatment prior to plasma treatment. The results revealed that nitrogen plasma treatment led to a substantial increase (25%) in bonding strength due to the synergistic effect of rough surface mechanical bonding and chemical bonding through functional groups between the aluminum alloy and GFRTP. However, the improvement in surface wettability by plasma treatment is time dependent and may gradually diminish over time due to the re-adsorption of hydrocarbon contamination from the surrounding air.

High-Cycle Fatigue Behaviour of the Aluminium Alloy 5083-H111.

This study presents a comprehensive experimental investigation of the high-cycle fatigue (HCF) behaviour of the ductile aluminium alloy AA 5083-H111. The analysed specimens were fabricated in the rolling direction (RD) and transverse direction (TD). The HCF tests were performed in a load control (load ratio R = 0.1) at different loading levels under the loading frequency of 66 Hz up to the final failure of the specimen. The experimental results have shown that the S-N curves of the analysed Al-alloy consist of two linear curves with different slopes. Furthermore, RD-specimens demonstrated longer fatigue life if compared to TD-specimens. This difference was about 25% at the amplitude stress 65 MPa, where the average fatigue lives 276,551 cycles for RD-specimens, and 206,727 cycles for TD-specimens were obtained. Similar behaviour was also found for the lower amplitude stresses and fatigue lives between 106 and 108 cycles. The difference can be caused by large Al6(Mn,Fe) particles which are elongated in the rolling direction and cause higher stress concentrations in the case of TD-specimens. The micrography of the fractured surfaces has shown that the fracture characteristics were typical for the ductile materials and were similar for both specimen orientations.

The Effect of Thickness on Strength of Single Lap Orbital Riveted Aluminum/Composite Joints Used in Marine Environments

In an innovative vision of manufacturing, orbital riveting is a joining technique characterized by high efficiency, energy saving, low costs and low noise. It is a cold forming process where a tool rotates at a fixed angle (i.e., typically 3° to 6°) to create a sweeping line of pressure around a rivet. This movement progressively promotes, with each rotation, the collapse of the rivet shank down onto the upper substrate of a joint, permanently forming a rivet head. The aim of this research is to make and test multi-material joints between an aluminum AA5083 H111 sheet and a glass fiber reinforced laminate. Specifically, nine configurations of single lap joints were studied by investigating the effect of the thickness (i.e., 2.5, 3.0 and 4.0 mm for the aluminum and 2.5, 3.0 and 4.0 mm for the composite laminate) both on the mechanical characteristics and on the failure modes.

Experimental and computational investigation of fatigue crack propagation using the inelastic energy approach

This study presents the experimental and computational investigation of a damage evaluation of the ductile aluminium alloy AA 5083-H111. The Compact Tensile (CT) specimen was selected for experimental testing and computational analysis. The proposed computational model is based on the inelastic energy approach, including the damage initiation and damage evolution criteria. In the computational model, the direct cyclic algorithm in the framework of Abaqus software was used to obtain the stabilised cyclic response of the analysed specimen subjected to the cyclic loading. Furthermore, the research presented in this study was focused mainly on the damage evolution period and subsequent determination of the appropriate maximum damage variable Dmax, which defines the stage of the stiffness degradation in the analysed structure, and, therefore, influence significantly on the damage evolution process.The comparison between the experimentally and computationally obtained damage evolution period and also the damage path in the analysed CT specimen showed a reasonable agreement. Therefore, it can be concluded that the proposed computational model was validated, and could be used for the further low cycle fatigue analyses of structural components made of the aluminium alloy AA 5083-H111.

Friction Stir Welded AA5052-H32 under Dissimilar Pin Profile and Preheat Temperature: Microstructural Observations and Mechanical Properties

In order to meet the escalating demand in the shipbuilding business, suitable materials with enhanced qualities are required to maximize ship cargo while reducing fuel consumption. Aluminum (Al) and its alloys are competing contenders for use in a variety of complicated ship structures. The major challenge to enhancing joint quality and performance is the quest for a viable and efficient FSW parameter. The main focus of this study was to critically explore the effect of the tool pin profile and the preheat temperature used during the friction stir welding of AA 5052-H32 on its mechanical properties and weld microstructure characteristics. There are three pin profile variations, including samples that were cylindrical, samples with two flat sides, and samples with three flat sides, all of which were investigated in different preheat temperatures (150–300 °C). The results that were obtained during macrographic observation showed that tunnel defects were visible in the cylindrical and two-flat-sided pin profile designs. During observations of the microstructure, it was observed that the grain size became finer and smaller in the weld nugget compared to in the heat affected zone (HAZ) and thermo-mechanically affected zone (TMAZ) regions due to dynamic recrystallization. However, at the 300 °C preheat variation, the grain size appeared to be larger due to the slower cooling rate, causing a decrease in the mechanical properties of the samples. The results of the physical tests determined that the preheat temperature caused an increase in the mechanical properties until 250 °C, at which point the three-flat-sided pin profile tool demonstrated superior mechanical properties compared to the tools with a cylindrical design; a 12.2% tensile strength increase, a 15.3% and 9.4% face and root bending increase, and an 11.2% hardness increase were observed.

Experimental investigation on adhesive bonding of similar and dissimilar weld joint used for automotive applications

The automobile industry has started using adhesive bonding to join load bearing components which aerospace industry has been using for decades. Adhesive lap joints are used frequently in the manufacture of automobile. In present study, structural adhesives were used to join the aluminium alloy (AA5083 H111) with the HSS dual phase (DP780) steel. Adhesive bonding appears to be one of the appropriate methods of joining dissimilar materials. The aim of this work is to analyze the tensile strength of similar and dissimilar joints. The influence of various parameters was also investigated such as the overlap length and the bondline thickness of specimens. In DP steel, there is 22% increase in strength for similar lap joint when overlap length changes from 10 mm to 15 mm, while there is 45% increase in strength when it varies from 15 mm to 20 mm. Similarly in case of Al alloy, there is 26% increased strength for similar lap joints when length varies from 10 mm to 15 mm, while it increased to 42% when length changes from 15 mm to 25 mm and there is about 35% increase in strength for length varies from 20 mm to 25 mm. In case of dissimilar joints, firstly there is about 16% increase in strength then there is 5% decrease while after that there is 45% increase in strength. Adhesion failure, cohesion failure and mixed failure were obtained experimentally during failure mode analysis. As the strength of joint increases, failure mode shows a transition from adhesion failure to cohesion failure. From the literature survey it is evident that limited work has been carried out on analysis of shear-tensile strength of adhesively bonded steel and aluminium joint with variation in bonding parameters. Not much work on failure mode analysis of bonded joints during tensile testing has been reported. In present work a noval attempt has been made to analyze the shear-tensile strength and failure mode of adhesively bonded steel and aluminium joint with variation in bonding parameters.

Experimental Investigation of Material Properties in FSW Dissimilar Aluminum-Steel Lap Joints

The friction stir lap welding of AA5083 H111 aluminum alloy and S355J2 grade DH36 structural steel was investigated. A polycrystalline cubic boron nitride with tungsten and rhenium additives tool was used. According to visual inspection, radiographic examination, and tensile test, it was observed that the best results were obtained for rotation speeds of about 700–800 rpm, with a feed speed ranging between 1.3 and 1.9 mm/s. From the fatigue tests, it is possible to state that there was a preferential propagation of cracks in the part of the aluminum alloy base material. Furthermore, a different response to fatigue stress for samples extracted from the same weld at different positions was observed, which introduces an overall variability in weld behavior along the welding direction. The specimens obtained in the second part of the weld endured a larger number of cycles before reaching failure, which can be related to progressively varying thermal conditions, dissipation behavior, and better metal coupling as the tool travels along the welding line.

Failure Strain and Fracture Prediction During Shock Tube Impact Forming of AA 5052-H32 Sheet

Abstract The present study deals with both numerical and experimental evaluation of failure strain and fracture pattern during shock tube impact forming of 1.5 mm thick AA 5052-H32 sheet. A hemispherical end nylon striker is propelled to deform the sheet at different velocities. Here, the main objective is to understand the effect of flow stress models and fracture models on the forming outputs. The experimental situation is modeled in two stages, i.e., incorporating the pressure in the first stage and displacement of the striker in the second stage in finite element simulation using the finite element (FE) code (DEFORM-3D). A new strategy followed to evaluate the rate-dependent flow stress data from the tensile test of samples sectioned from shock tube-based deformed sheet is acceptable, and finite element simulations incorporating these properties predicted accurate failure strain and fracture pattern. Out of all the flow stress models, the modified Johnson–Cook model has a better flow stress predictability due to the inclusion of the non-linear strain rate sensitivity term in the model. During the prediction of the failure strain and necking location, the Cockcroft–Latham failure model, Brozzo failure model, and Freudenthal failure model have a fair agreement with experimental data in combination with the two flow stress models, i.e., Johnson–Cook model and modified Johnson–Cook model.

Experimental and Numerical Investigation of AA5052-H32 Al Alloy with U-Profile in Cold Roll Forming.

The cold roll forming process is broadly used to produce a specific shape of cold-roll formed products for their applications in automobiles, aerospace, shipbuilding, and construction sectors. Moreover, a proper selection of strip thickness and forming speed to avoid fracture is most important for manufacturing a quality product. This research aims to investigate the presence of longitudinal bow, the reason behind flange height deviation, spring-back, and identification of thinning location in the cold roll-forming of symmetrical short U-profile sheets. A room temperature tensile test is performed for the commercially available AA5052–H32 Al alloy sheets using Digital Image Correlation (DIC) technique, which allows complete displacement and strain data information at each time-step. The material properties are estimated from the digital images using correlation software for tested samples; the plastic strain ratios are also calculated from samples at 0°, 45°, and 90° to the rolling direction. The tested sample’s surface morphology and the elemental analysis are conducted using scanning electron microscopy (SEM) method and energy-dispersive X-ray spectroscopy (EDS) analytical technique combined with element mapping analysis, respectively. The cold roll forming experiments are systematically carried out, and then finite element analysis is utilized to correlate the experiment with the model. The performed cold roll forming numerical model outcome indicates a good agreement with the experimental measurements. Overall, the presented longitudinal strain was observed to influence the geometry profile. The spring-back is also noticed at the profile tail end and is more pronounced at high forming speed with lower strip thickness. Conversely, while the forming speed is varied, the strain and stress variations are observed to be insignificant, and the similar results also are recognized for the thinning behavior.

Low cycle fatigue behaviour of ductile aluminium alloys using the inelastic energy approach

This study presents the experimental and computational investigation of the low cycle fatigue behaviour of the ductile aluminium alloy AA 5083-H111 using the inelastic energy approach. The proposed computational model consists of a damage initiation and damage evolution period considering a complete history of the cyclic stress-strain response previously determined using LCF-tests. In computational modelling, the nonlinear isotropic/kinematic hardening is considered using the Chaboche constitutive equations, while the direct cyclic algorithm implemented in the Abaqus/Standard software is used to obtain the stabilised response of a specimen subjected to the cyclic loading. In order to examine the damage evolution paths, finite elements with severe damage are detected, and then removed from the finite element model in the subsequent numerical simulations.The proposed material model was validated by the comparison of the computationally and experimentally determined history of hysteresis loops and complete damage behaviour considering both damage initiation and the damage evolution period. Although the proposed approach has been validated for the aluminium alloy AA 5083-H111 with the characterised microstructure, it may also be used to simulate the fatigue behaviour of others ductile Al-alloys where the microstructure may be different. In such cases, a new LCF-test should be necessary to obtain the appropriate cyclic stress-strain responses.

Multi-response optimization of process parameters in friction stir welding of dissimilar aluminum alloys by Grey relation analysis (AA 6061-T6 & AA5083-H111)

In the fusion of different solid-state alloys (150X150X6 mm) friction stir welding techniques are carried out using rotational speeds, transverse speeds and varying pin profiles. Emerging trends to join different alloys, heat-treated (AA 6061-T6) and non-heat can be treated (AA 5083-H111) is an important part of the joining dissimilar alloys. In this investigation, the experimental design using the response surface method must predict the parameters of the optimized welding method by using non-linear multi responsive optimization techniques. This technique, while using applications for experimental observations developed the mathematical model, must achieved the welding standards using optimal input and output parameters. These results use a confirmation process with reference to the ANOVA model which is used to develop and find out the optimal value of defect-free welding. It has developed a multivariate mathematical analysis for the relationship between the mechanical properties of the model. And using a scanning electron microscope from a microstructure must reveal dominant problems such as tunnel formation defects, voiding, plunging, etc.

Microstructure and Low Cycle Fatigue Properties of AA5083 H111 Friction Stir Welded Joint.

The present paper aims to analyze the microstructure, microhardness, tensile properties, and low cycle fatigue (LCF) behavior of friction stir welded (FSW) butt joints. The material used in this study was the 5 mm thick 5083 H111 aluminum alloy sheet. Butt joints of AA 5083 H111 were manufactured at different operating parameters of the FSW process. The effect of the welding parameters on microstructure, microhardness, and tensile properties was investigated. Based on microstructure analysis and strength tests, the most favorable parameters of the FSW process were settled on the point of view of weld quality. Then, LCF tests of base material and friction stir welded specimens made of 5083 H111 were carried out for the examined welded samples under selected friction stir welding parameters. The process of low-cycle fatigue of 5083 H111 aluminum alloy was characterized by cyclic hardening for both: base material and FSW joint. It was revealed by a decrease in the width of the hysteresis loop with the simultaneous significant increase in the values of the range of stress. It was determined that fatigue cracks are initiated by cyclic slip deformation due to local stress concentration from the surface in the corner of the samples for the base material and the heat-affected zone for FSW joints. For all tested strain amplitudes, the fatigue crack propagation region is characterized by the presence of fatigue striation with secondary cracks.

Forming response of AA5052–H32 sheet deformed using a shock tube

Abstract The effect of bending pre-strain and pressure on the forming behavior of AA5052–H32 sheets has been studied using a shock tube. Various forming parameters like dome height, effective strain and stress distribution, hardness, and grain size evolution have been measured. Circular grids are printed on the sheets and Hill's 1948 yield criterion is used to calculate the effective strain distribution. The effective stress distribution is calculated by using the Hollomon's power law. The strain evolution during the forming process is monitored by mounting a strain rosette at the mid location of the sheet. The strain–time graph confirms the sharp rise in the peak strain and it increases significantly at higher pressure. The variation in the forming parameters asserts that the material stretches uniformly without strain localization. The optical microstructures also depict that the equiaxed grains are stretched and elongated after the shock deformation. This analysis confirms that the forming behavior of the material is dependent both on the degree of pre-strain and the change in pressure.