Alloy AA2024-T3 Research Articles

Effect of Cutting Parameters and Tool Geometry on the Performance Analysis of One-Shot Drilling Process of AA2024-T3

Drilling is an important machining process in various manufacturing industries. High-quality holes are possible with the proper selection of tools and cutting parameters. This study investigates the effect of spindle speed, feed rate, and drill diameter on the generated thrust force, the formation of chips, post-machining tool condition, and hole quality. The hole surface defects and the top and bottom edge conditions were also investigated using scan electron microscopy. The drilling tests were carried out on AA2024-T3 alloy under a dry drilling environment using 6 and 10 mm uncoated carbide tools. Analysis of Variance was employed to further evaluate the influence of the input parameters on the analysed outputs. The results show that the thrust force was highly influenced by feed rate and drill size. The high spindle speed resulted in higher surface roughness, while the increase in the feed rate produced more burrs around the edges of the holes. Additionally, the burrs formed at the exit side of holes were larger than those formed at the entry side. The high drill size resulted in greater chip thickness and an increased built-up edge on the cutting tools.

Improving the Quality of Friction Stir Welds in Aluminium Alloys

The Stationary Shoulder Friction Stir Welding (SS-FSW) technique benefits from reduced heat input, improved mechanical properties and surface finish of the weld, avoiding the need for post weld processing. Coatings on the tool probe and the shoulder for welding of aggressive Aluminium alloys have rarely been successful. Such coatings must be well adherent and inert. In this study, coated tools were used for SS-FSW of AA6082-T6 alloy. Performance of a nanoscale multilayer TiAlN/VN coating deposited by High Power Impulse Magnetron Sputtering (HIPIMS) technology was compared with amorphous Diamond Like Carbon (a-C:H) by Plasma Assisted Chemical Vapour Deposition (PACVD), AlTiN deposited by arc evaporation and TiBCN along with TiB2 produced by Chemical Vapour Deposition (CVD) methods. The TiAlN/VN coating was found to have low affinity to aluminium, acceptable coefficient of friction and provided excellent weld quality by inhibiting intermixing between the tool and workpiece materials resulting in a significant reduction in tool wear.

Multi-response mathematical model for optimization of process parameters in CMT welding of dissimilar thickness AA6061-T6 and AA6082-T6 alloys using RSM-GRA coupled with PCA

The requirement projected by many industries for stronger, lighter, more efficient and cost-effective combined alloys in the welding of two dissimilar materials or dissimilar thickness. The current industry trend is the coalescence of various aluminium alloys of varying thicknesses. In this research paper, Cold Metal Transfer (CMT) welding process was used for the joining of AA6061-T6 and AA6082-T6 using ER4043 filler wire and inspected the effect of different process parameters on mechanical properties of welded butt joints. Current (I), welding speed or travel speed (TS) and gas flow rate (Q) are the input welding process parameters that are to be optimized. Full factorial central composite face-centered design (CCFCD) was utilized to optimize the tensile properties, microhardness and residual stresses. Grey relation analysis (GRA) with PCA is incorporated with CCFCD for finding out the optimal process parameter by considering multi-response parameters simultaneously. ANOVA was executed to interpret the impact of a process parameter on the mechanical properties of the weldments. Results showed that the most dominant process parameter was found to be the welding speed. The optimal process parameter obtained via the GRA-PCA technique is I3-TS1-Q1 (I - 100 A, TS - 5 ​mm/s and Q - 14 ​L/min having heat input 352 ​J/mm) which produces 226 ​MPa of ultimate tensile strength, 12.6% of elongation, 68.7 HV of microhardness and −152.3 ​MPa of compressive residual stress. The desirability of optimality level obtained through CCFD was 65.99% and significantly improved to 97.07 through GRA-PCA.

An investigation into the Role of the Acid Catalyst on the Structure and Anticorrosion Properties of Hybrid Sol-Gel Coatings

This paper investigates the role of the acid catalyst on the structure and anticorrosion barrier performances of a dual hybrid sol-gel coating composed 3-trimethoxysilylpropylmethacrylate and a zirconium complex and deposited on AA2024-T3 alloy. Along with the variation of the acid catalyst in the range 0.3 to 2, the zirconium complex concentration in the silicate matrix is altered from 10 to 30%. Mol.The structure of the materials is characterised using dynamic light scattering, Fourier-transform infrared spectroscopy, and 29Silicon nuclear magnetic resonance spectroscopy, while the thermal behaviour is identified by differential scanning calorimetry and the coating morphology analysed using scanning electron microscopy/energy dispersive x-ray spectroscopy. The anticorrosion barrier properties are characterised by electrochemical impedance spectroscopy and neutral salt spray.It is shown that the acid catalyst concentration has a direct impact on the kinetics of the hydrolysis and condensation reactions and that those effects can be controlled by the content of zirconium. These individual or combined alterations are found to directly impact the formation of Si-O-Zr bonds, thus the interconnectivity between the silicate matrix and the zirconium complex modifier, resulting in hybrid structures with altered densities. For the materials composed of 10 and 20 % of zirconium complex and when the pH is lowered, the relative concentrations of siloxane bonds is increased at the expenses of the Si-O-Zr bonds. When the concentration of zirconium complex is increased to 30 % and as the pH is increased, a higher competition in the formation of Si-O-Zr bonds takes place and are preferentially formed over the higher condensed Si-O-Si bonds.The corrosion testing show that the coatings with the highest barrier properties are found when the interconnectivity between the silicate and zirconium complex is maximum, thus for the materials exhibiting the highest condensation degrees.

Mechanical Parameters Response on Micro-Friction Stir Welding of AA6061 and SS304 Sheets

Friction stir welding is a contact welding process that uses the heat generated by friction to fuse two different materials. This work is focused on the development of micro-friction stir welding which is carried out for very thin sectioned materials of thickness 1000[Formula: see text][Formula: see text]m or less. Friction welded butt-joints were successfully produced for 0.8[Formula: see text]mm thin AA6061 and SS304 sheets on a semi-automated vertical milling machine using a zero-pin length tool. A mild steel backing plate is used as fixture mechanism to hold the welding sheets on machine. Tool-rotational speed and Tool-travel speed are the weld-parameters examined on mechanical responses such as tensile behavior, micro-hardness and surface-roughness across the nugget-weld zone interface. The maximum tensile strength is obtained at lower weld-parameters. Tensile strength properties of AA6061-T6/SS304 joints were approximately found to be 25% lower than that of the AA6061-T6 alloy base metal. Maximum hardness value of 93HV and minimum roughness value of 2.808[Formula: see text][Formula: see text]m are observed for higher tool speeds at nugget-weld zone interface due to the formation of intermetallic phases. Microstructural behavior is studied on weld-parameters using scanning electron microscope and energy dispersive X-ray analyzer. Very thin intermetallic layers (consisting of Fe2Al5, FeAl3 and FeAl2 phases) were observed in stainless steel/aluminum interface.

Effect of Number of Passes on Surface Properties of Burnished Aluminium Alloy

Basically, roller burnishing process is one of the surface finishing processes. In this process, a hard and highly polished roller will be pressed against a rotating specimen, this causes plastic flow on specimen surface from the peaks of surface irregularities into the valleys, which results in a reduction in the surface roughness considerably. This is a type of cold working whichalso results in improvementof micro-hardness, refinement of microstructure on the surface of the specimen under consideration. This work aims to understand the versatility of roller burnishing processand to understand the effect of the number of burnishing passes to enhance surface properties. Surfaceroughness, electrical conductivityand microhardness were studied in the present work. Experimental work was done on aluminium AA7075-T6 alloy. The parameters under which the burnishing was done were burnishing force, spindle feed and speed and are kept constant in the present work.

Multiscale investigation of corrosion damage initiation and propagation in AA7075-T651 alloy using correlative microscopy

The evolution of the overall microstructure and contribution of constituent second phase particles during the accelerated corrosion of AA 7075-T651 warrants further scrutiny. A correlative microscopy-based approach was employed to study corrosion damage evolution in the microstructure of AA 7075-T651 subjected to potentiodynamic polarization. X-ray Computed Tomography (XCT) and scanning electron microscopy were used to track corrosion damage initiation and propagation globally and at specific regions of the microstructure starting from the first breakdown potential. Additionally, Focused Ion Beam and Electron Backscattered Diffraction were used to investigate local corrosion processes such as pitting and intergranular corrosion. Interesting concentric corrosion patterns, Fe-rich intermetallic particle dissolution and exfoliation corrosion were observed and mechanisms for the same have been proposed.

Refill friction stir spot welding of aerospace alloys in the presence of interfacial sealant

Refill friction stir spot welding (refill FSSW) is one of the most industrially promising friction stir spot welding variants. The absence of an exit hole improves the effectiveness of surface treatments and minimizes damage by fouling. Aerospace aluminium alloys AA2024-T3 and AA7075-T6 with a thickness of 2 mm were used in this investigation. A range of values for rotation speed and plunge depth were experimented to determine the most promising process parameter combination based on the cross-sectional analysis and lap shear strength. The effect of an interfacial sealant on the weld properties was determined for both alloys using the most promising process parameter combination. Fatigue life analysis and fractography using scanning electron microscopy were performed for specimens with and without sealant.

Friction drilling of AA7075-T6 and AZ31B alloys under dry and oil containing ceramic particulates

This study investigates the friction drilling behaviors of AA7075-T6 aluminum and AZ31B magnesium alloys containing ceramic powders of B4C, SiC, and Al2O3 under dry and minimum quantity lubrication (MQL). The aim is to create a composite structure while applying the pressure of a drilling tool on the hole surface when adding ceramic powders into the cutting oil during frictional drilling. Friction drilling tests are performed at a constant spindle speed and feed speed, and the effects of dry and cutting oil mixtures containing ceramic particulates on the thrust force, temperature, hole surface quality, bushing profile, and thread stripping strength of the specimens are investigated. The results revealed that ceramic particles penetrated through the hole and created a composite structure on the surface. The dry friction drilling of AA7075-T6 and AZ31B yielded acceptable surface quality. However, the surface quality worsened considerably during the friction drilling of AA7075-T6 using the oil mixture, whereas the surface roughness and hole bushing of AZ31B magnesium alloys are not negatively affected by the ceramic containing oil mixtures. Petal formation and cracks appeared in the hole profiles of the AA7075-T6 aluminum alloy. Thread stripping tests indicate that the ceramic-particle- containing oil mixtures enhanced the thread shear strength of AA7075-T6 by 19.2 %, and the highest shear strength of 56.78 kN is achieved using the Al2O3 containing an oil mixture. The oil mixture-containing B4C ceramic particles improved the thread shear strength of AZ31B by 7.7 %.

The role of brass texture on the deformation response of 7075-T651 aluminum alloy under equi-biaxial tension

Cruciform specimen is utilized to study the influence of equi-biaxial stress state on the plastic strain response of AA7075-T651 alloy until fracture. The failure ductility as a function of stress state is evaluated using non-contact digital image correlation technique. The distinct biaxial deformation behavior in contrast to uniaxial response is attributed to strong crystallographic texture developed during prior hot-rolling reduction. The weakening of initial brass texture upon equi-biaxial deformation is also evident from the orientation distribution analysis. Increased activity of grain boundary assisted cracking due to increased stress triaxiality due to biaxial loading is evident, when compared to uniaxial stress state. • Cruciform specimen is used to capture the plastic strain response of 7075-T651 aluminum alloy until fracture. • Severe reduction in ductility with concomitant improvement in yield strength observed under biaxial condition. • Increased occurrence of grain-boundary assisted cracking corroborates decreased ductility under equi-biaxial stress state. • Brass texture component {0 1 1} < 5 3 ‾ 3> contributed to the observed biaxial strengthening effect.

Applicability of unique scarf joint configuration in friction stir welding of AA6061-T6: Analysis of torque, force, microstructure and mechanical properties

The present research introduces a unique concept of scarf joint technique in friction stir welding (FSW) of aluminum alloy AA 6061-T6 plates and an investigation on weld quality. A new joint configuration with two distinct scarf angles (75° and 60°) was considered in this study. The various aspects of welding were compared with contemporary simple square butt (SSB) joint configuration. Welding was carried out at a constant tool rotation speed (TRS), tool traverse speed (TTS) and tool tilt angle of 1100 rpm, 2 mm/s and 2°, respectively. The results are analyzed in terms of force and torque distribution, microstructure, macrostructure, and mechanical property perspective for different joint configurations. The study reveals the minimum amount of force and torque at 60° scarf angle joint configuration compared to that of square butt joint configuration. Macro study shows that all the joints were defect-free, and a prominent onion ring was present in the lower portion of the weld nugget (WN). Fine equiaxed grains with a minimum average grain size diameter of 6.82 μm were obtained in the WN of scarf joint configuration (SJC). The maximum ultimate tensile strength (UTS) and maximum average NZ hardness of 267 MPa and 83.82 HV0.1 were obtained in SJC3 at a scarf angle of 60°. It has been observed from the investigation that the joint efficiency increases from 72.5% (SSB) to 86% (SJC3) at a 60° scarf angle. This unique characteristic may lay an impetus on probable joint strength enhancement technique without increasing the production cost.

Coupled Eulerian–Lagrangian prediction of thermal and residual stress environments in dissimilar friction stir welding of aluminum alloys

The evaluation of residual stresses (RS) induced by the friction stir welding (FSW) process is crucial in anticipating the performance of the welded structure. The existence of such residual stresses within a friction stir welded structure may lead to excessive distortion and weakness to afford the applied external loads. To assess quantitatively the effect of these residual stresses generated by FSW process, the current paper implements a Coupled Eulerian–Lagrangian (CEL) finite element simulation to analyze both thermal and subsequent resulted remaining stress environments in dissimilar friction stir welding of AA6061-T6 and AA2024-T3 alloys. The thermal analysis step was conducted first and followed by a mechanical analysis step in which the residual stresses distribution throughout the whole dissimilar FSWed alloys were captured. To validate the simulation results, K-type thermocouples, in addition to A-type rosette strain gauges, were planted to measure both temperature history and residual stress field generated as a consequence of the thermal environment. The effect of changing FSW working variables like rotation and traverse speeds on both the thermal and residual stress environments was investigated. The obtained results demonstrated that the temperature, as well as the residual stress, was higher in the sample retreating side rather than the proposed advancing side, and a fair correlation between the experimental and simulation results was attained. Quantitatively, the longitudinal residual stress was higher in contrast to the transverse value, and it varied from being tensile in the zone beneath the tool shoulder to compressive away from the welding tool. Furthermore, the plastic strain produced owing to the surface contact between the welding tool and the dissimilar aluminum sample was higher on the retreating side.

Effect of tool travel speed on tensile strength of friction stir welded dissimilar joint of aluminium AA6061 T6 alloy and maraging M250 steel

Friction stir welding (FSW) is a promising welding method to produce dissimilar joints between steel and aluminium. The formation of the intermetallic compound layer at the dissimilar joint interface affects the joint mechanical properties, which are also influenced by the FSW process parameters. In the present research work, M250 Maraging steel and AA6061 T6 aluminium alloy were joined by FSW. The joints were prepared with five different tool travel speeds ranging from 0.33 mm s−1 to 1 mm s−1 using a tapered tool pin made by tungsten carbide material, keeping tool rotational speed constant. The welded joints were analyzed for their tensile behaviour and microstructural change, including hardness measurement. The failed samples are analyzed using a scanning electron microscopy device for their mode of failure. In the Energy Dispersive X-Ray Spectroscopy (EDS) analysis, the formation of intermetallic compound (IMC) layers of Fe3Al, Fe4Al13, and Fe2Al5 are observed. When the thickness of the IMC layer increases, the joint strength decreases. It is found that the welding speed influences the thickness of the IMC layer formed, causing variation in the strength of the dissimilar joint. Better joint efficiency is obtained at a tool travel speed of 0.67 mm s−1.

The Role of the Fiber/Bead Hierarchical Microstructure on the Properties of PVDF Coatings Deposited by Electrospinning.

Among the various polymeric options employed for the deposition of electrospun coatings, poly(vinylidene fluoride) (PVDF) has been widely investigated thanks to its excellent mechanical properties, high chemical resistance, and good thermal stability. In this work, the electrospinning technique is used for the fabrication of functional PVDF fibers in order to identify and evaluate the influence of the experimental conditions on the nanofiber properties in terms of optical transmittance, wettability, corrosion resistance, and surface morphology. Some of these properties can play a relevant role in the prevention of ice formation in aircrafts. According to this, a matrix of 4 × 4 samples of aluminum alloy AA 6061T6 was successfully coated by controlling two operational input parameters such as the resultant applied voltage (from 10 up to 17.5 KV) and the flow rate (from 800 up to 1400 µL/h) for a fixed polymeric precursor concentration (15 wt.%). The experimental results have shown a multilevel fiber-bead structure where the formation of a fiber mesh directly depends on the selected operational parameters. Several microscopy and surface analysis techniques such as confocal microscopy (CM), field emission scanning electron microscopy (FE-SEM), UV/vis spectroscopy, and water contact angle (WCA) were carried out in order to corroborate the morphology, transmittance, and hydrophobicity of the electrospun fiber composite. Finally, the corrosion behavior was also evaluated by electrochemical tests (Tafel curves measurement), showing that the presence of electrospun PVDF fibers produces a relevant improvement in the resultant corrosion resistance of the coated aluminum alloys.

WITHDRAWN: Optimization of shot peening process parameters using PSO algorithm to maximise the fatigue strength, flexural strength and surface hardness of AA2024-T3 alloy

Shot peening (SP) process is performed on AA2024-T3 alloy to improve its fatigue strength, flexural strength and surface hardness. Response surface method (RSM) is used for designing the experiments. Experiments are conducted and the regression equations are framed using the Design Expert software. RSM based second order regression equations are used as input to Particle swarm optimisation (PSO) algorithm. PSO algorithm is used to find the best combination of shot peening process parameters, namely, peening pressure and peening distance for maximizing the responses. Validation of the solutions obtained from PSO is done by performing shot peening process with nickel balls. The results of mechanical properties of AA2024-T3 are found close to the predicted values obtained from PSO algorithm.

Microstructural evolution in friction self-piercing riveted aluminum alloy AA7075-T6 joints

Friction self-piercing riveting (F-SPR) is an emerging technique for low ductility materials joining, which creates a mechanical and solid-state hybrid joint with a semi-hollow rivet. The severe plastic deformation of work materials and localized elevated temperatures during the F-SPR process yield complex and heterogeneous microstructures. The cut-off action of the work materials by the rivet further complicates the material flow during joint formation. This study employed the F-SPR process to join AA7075-T6 aluminum alloy sheets and systematically investigated the microstructural evolutions using electron backscatter diffraction (EBSD) techniques. The results suggested that as the base material approached the rivet, grains were deformed and recrystallized, forming two distinct fine grain zones (FGZs) surrounding the rivet and in the rivet cavity, respectively. Solid-state bonding of aluminum sheets occurred in the FGZs. The formation of FGZ outside the rivet is due to dynamic recrystallization (DRX) triggered by the sliding-to-sticking transition at the rivet/sheet interface. The FGZ in the rivet cavity was caused by the rotation of the trapped aluminum, which created a sticking affected zone at the trapped aluminum/lower sheet interface and led to DRX. Strain rate gradient in the trapped aluminum drove the further expansion of the sticking affected zone and resulted in grain refinement in a larger span.

Comparison of the Weldability of AA6061-T6 Joint under Different Friction Stir Welding Conditions

In this work, similar butt joints of AA6061-T6 alloy prepared by underwater friction stir welding (UWFSW) and friction stir vibration welding (FSVW) processes were examined. The characteristics of joints were compared with the joints obtained by conventional friction stir welding (CFSW). The different kinds of microstructural modifications that occurred during CFSW, FSVW, and UWFSW processes were analyzed. The results are employed to analyze the different behaviors in strength, ductility, weldability, and hardness of the joints in different processes at different traverse speeds, rotational speeds, and vibration frequency. It was found that mechanical vibration decreases the grain size in the weld zone and hinders the coalescence and regrowth of the precipitates during FSVW. On the other hand, water significantly decreased the joint temperature during UWFSW and led to a refined microstructure in the stir zone, which substantially improved the mechanical properties of the welded joint. The synergetic effect of refined grains and lower dissolution of β″ precipitates (higher evolution of β″ to β′ and β-Mg2Si) due to fast cooling rate (intensified local deformation) led to higher hardness in UWFSW (FSVW) joint compared to CFSW joint. The small size with the uniform distribution of dimples indicated the combination of strength and ductility in FSVW-ed and UWFSW-ed joints. The simple and highly effective welding procedure, FSVW, can be readily scaled up for industrial welding applications.

EBSD Study on Two Modes of Metal Flow Transfer in Friction Stir Weldment

In this study, the metal flow phenomenon of friction-stir-welded AA6082-T6 and AA2014-T6 alloys is studied in detail and correlated with hardness measurement. The FSW process was carried out with optimized process parameters obtained from Taguchi’s method L9 orthogonal array of tool rpm (1200 rpm), welding speed (70 mm/min) and tilt angle of 2°. Cross-sectional view of dissimilar weldment interestingly showed the two modes of metal flow phenomenon within the weld matrix. EBSD analysis revealed that the weld matrixes of first mode region had almost equal fractions of LAGBs and HAGBs, whereas the second mode region had the lower fractions of LAGBs compared to HAGBs, which was due to the severe plastic deformation associated with tool shoulder.

Machinability studies of AA2024-T351 alloy with uncoated carbide tool

AA2024-T351 alloys are widely used in aerospace and automotive industries due to their high strength to weight ratio and ductility. The present paper investigates the machinability of AA2024-T351 material with uncoated carbide tools. Orthogonal machining experiments were performed at varying cutting speeds and feed rates with a constant depth of cut. Machinability studies were done using cutting forces, coefficient of friction and chip morphology. As the feed rate increased both cutting force and feed forces were found to be increased whereas the coefficient of friction decreased. Chip formation process was significantly influenced by the operating conditions. In addition, the shear angle and contact length were determined analytically.

Simulating the Effect of Temperature Gradient on Grain Growth of 6061-T6 Aluminum Alloy via Monte Carlo Potts Algorithm

During heat treatment or mechanical processing, most polycrystalline materials experience grain growth, which significantly affects their mechanical properties. Microstructure simulation on a mesoscopic scale is an important way of studying grain growth. A key research focus of this type of method has long been how to efficiently and accurately simulate the grain growth caused by a non-uniform temperature field with temperature gradients. In this work, we propose an improved 3D Monte Carlo Potts (MCP) method to quantitatively study the relationship between non-uniform temperature fields and final grain morphologies. Properties of the aluminum alloy AA6061-T6 are used to establish a trial calculation model and to verify the algorithms with existing experimental results in literature. The detailed grain growth process of the 6061-T6 aluminum alloy under different temperature fields is then obtained, and grain morphologies at various positions are analyzed. Results indicate that while absolute temperature and duration time are the primary factors determining the final grain size, the temperature gradient also has strong influence on the grain morphologies. The relationships between temperatures, temperature gradients and grain growth process have been established. The proposed MCP algorithm can be applied to different types of materials when the proper parameters are used.