Aluminum Alloy AA Research Articles

Achieving microstructural homogeneity in the stir zone across thick AA6061 welds using self-reacting bobbin tool friction stir welding

This study focuses into strategizing the usage of self-reacting bobbin tool friction stir welding (SRBT-FSW) to obtain consistent microstructural homogeneity along the thickness of AA6061 aluminium alloy (AA) thick plates during welding. The SRBT-FSW technology, distinguished by its dual-shoulder design, represents a significant step forward in FSW by eliminating the requirement for a backing anvil and promoting balanced heat distribution. This study seeks to address the issues of maintaining uniform microstructural characteristics throughout the weld zone, which is crucial for the mechanical performance and durability of welded joints in structural applications. The experimental study entails the systematic welding of AA6061 plates of 6 mm thickness using a self-reacting bobbin tool under a fixed processing condition. Electron backscatter diffraction (EBSD) was used to characterize the grain structure and phase distribution over the weld. Mechanical parameters like as tensile strength and hardness were determined to establish correlations between microstructure and mechanical performance. The results demonstrated that SRBT-FSW significantly enhances microstructural homogeneity across the weld zone, leading to improved mechanical properties. In the Bottom Zone (BZ), a refined grain structure with an average grain size (AGS) of 3.53 µm and a random or weak texture was observed, contributing to enhanced hardness and mechanical performance, with an ultimate tensile strength (UTS) of 220 MPa. In contrast, the Top Zone (TZ) exhibited a coarser AGS of 4.33 µm with a pronounced {111} crystallographic texture, resulting in a slightly lower UTS of 205 MPa. The Middle Zone (MZ), influenced by the greater heat input from both the TZ and BZ, showed an intermediate AGS of 3.99 µm, predominantly oriented along the {101} plane, and achieved a UTS of 194 MPa, with a slight reduction in ductility. This study highlights the potential of self-reacting bobbin tool friction stir welding as a reliable method for making high-quality, homogeneous welds in thick aluminium plates and paving way for their wider application in the aerospace, automotive, and shipbuilding industries, where homogeneous microstructural qualities are of significant importance.

Surface chemistry characterization of AA2014 aluminum alloy powder through triboelectric charging

Traditional characterization techniques for powders primarily focus on bulk properties, often neglecting the critical role of surface chemistry variations that influence the performance in applications such as additive manufacturing. The method presented in this work addresses this gap by utilizing triboelectric charging concept to gain a comprehensive understanding of powder surface state under varying environmental conditions. In particular, the study investigates the detection of surface chemistry variations of AA2014 powder caused by an exposure to various relative humidity (RH) levels through a change in triboelectric charging behavior. The surface variations are analyzed in parallel with X-ray photoelectron spectroscopy (XPS). The findings reveal a direct correlation between elevated RH and increased hydroxide species content at the surface of the powder. The triboelectric charging experiments demonstrated a significant RH-dependent variations of charge accumulation, with higher humidity levels leading to reduced static charge buildup on the powder particles. The charge accumulation behavior in the powder was fitted with the compressed exponential relaxation model. The results showed that each surface chemical species exhibits a distinct correlation between charging rate and charge accumulation, confirming the method's effectivity to detect subtle variations in surface chemistry. The variations in the exponent of the fitted model were shown to be characteristics to the surface scale of the powder particles.

High-Velocity Impact Response of Directly Recycled Aluminium Alloy AA6061 Plates

High-Velocity Impact Response of Directly Recycled Aluminium Alloy AA6061 Plates

Investigation of the Process Parameters in Rotary Friction Welded Dissimilar AA7075/AA5083 Aluminum Alloy Joints on Fatigue Initiation using FEA and ANN

The rotary friction welding (RFW) method is one of the most widespread methods in the world for producing bimetallic components that require high mechanical strength. Simulations play a vital role in improving energy efficiency and reducing environmental impact, aligning with the sustainability goals of modern industry. A neural network (NN)-based incremental learning system was developed to predict crack growth and fatigue for AA5083 and AA7075 aluminum alloys. The results indicate the ability of this method to accommodate the input temperatures and the S-N curve and provide reliable predictions of expected fatigue. This method can reduce labor costs and time spent on crack propagation tests, enhancing the effectiveness of production processes and reducing process costs. This work also reveals the ability of neural . It maynetworks (NN) in monotonic function extrapolation like the S-N curve, which may pave the way for a wide variety of monotonic function-predicting problems. In future studies, a neural network (NN)-based increment learning scheme could be trained with random parts of individual S–N curves and applied to predict the rest. Additionally, the verification utilizing AISI 2205 and AISI 1020 steel has observed that neural networks may obtain S-N curve values for another metal with less than an 8% error rate. Friction pressure increases temperature, deformation, and stress in welding processes. Friction pressure 17 MPa increases temperature to 355 degrees Celsius, while Friction pressure 23 MPa increases deformation to 0.020 mm. A friction pressure of 29 MPa increases equivalent stress to 110 MPa. The indication of the S-N curve shows that increasing welding pressure increases Alternating Stress. Friction pressure also increases life, with minimum life cycles reaching 171040 cycles at 17 MPa, 195560 cycles at 23 MPa, and 283690 cycles at 29 MPa. Comparing research and simulation results, convergence is less than 8%, reducing error.

Effect of Alkaline Etching on Formation Behavior and Corrosion Resistance of a Cr-Zr-Ti TCP Conversion Coating on AA2024 Aluminum Alloy

Abstract Trivalent chromium process conversion coating is considered to be the ideal alternative to traditional chromate conversion coating due to its high corrosion resistance and low toxicity. However, achieving a high corrosion resistance trivalent chromium conversion coating on 2xxx aluminum alloys has been a great challenge. Herein, based on a newly developed trivalent chromium conversion solution (CN patent, ZL 202210804263.2), the effect of alkaline etching on the formation behavior and corrosion resistance of the coating on AA2024-T351 aluminum alloy was investigated. It was found that under the same conditions, the mechanically polished sample and the sample alkaline etched for 30 s showed the highest corrosion resistance. When the alkaline etching time was too short or too long, the corrosion resistance of the coating deteriorated. This is ascribed to changes in the surface microstructure of the alloy during alkaline etching, i.e., reduced number of intermetallic particles and formation of a copper enrichment layer. Reducing the number of intermetallic particles on the alloy surface is beneficial for uniform growth of the coating. However, the copper enrichment layer participated in formation of the coating, resulting in doping of copper species in the coating, which is detrimental to the corrosion resistance of the coating.

Effect of high pressure-low plasticity burnishing on the mechanical and microstructural behaviour of copper foil interlayered FSW aluminium alloys

Abstract This study delves into the impact of high pressure-low plasticity burnishing (HP-LPB) on the mechanical and microstructural behaviour of friction stir welding (FSW) joints, specifically involving AA5052 and AA6082 aluminium alloys. Notably, copper foil (CF) is introduced as a novel element in the HP-LPB process to enhance the weld strength. The experiments were conducted with the tool rotational speeds (TRS) of 1000, 1100, and 1200 RPM, each paired with the welding speeds (WS) of 20, 25, and 30 mm min−1, and tool tilt angle (TTA) of 0°, 1°, and 2°. Mechanical behaviour is assessed through tensile testing along with microhardness measurements, revealing the advantages of HP-LPB with CF in enhancing joint strength and toughness. The microstructural analysis reveals the dissolution of precipitates, highlighting the influential role of copper foil in the improvement of joint efficiency. From the weld without a CF interlayer, a maximum tensile strength of 188 MPa was achieved at a TRS of 1200 RPM, WS of 25 mm min−1 and TTA of 2°. The post-processed FSW sample interlayered with copper foil, exhibited an improvement in joint efficiency by 87% at the optimum process parameter. This research demonstrates that the use of copper foil interlayers combined with HP-LPB treatment can substantially enhance the mechanical properties and structural integrity of FSW aluminum alloys, offering a valuable solution for advanced industrial applications.

Enhancement of Mechanical Properties and Microstructure of Aluminium alloy AA2024 By adding TiO2 Nanoparticles

Modern engineering applications, especially in the automotive and aerospace industries, require essential and appealing properties such as lightweight with high strength and resistance. The key objective of the present study is to investigate the effect of TiO2 nanoparticles on the microstructure, impact strength, hardness and wear resistance of the stir cast aluminum alloy AA2024, An aluminium alloy was reinforced with different mass fractions (0 %, 2.5 %, 5 %, 7.5 %) of titanium dioxide nanoparticles by stir casting followed by solution annealing at 500°C for 3 h, quenching in water and aging at 175°C for 3 h. Results showed that regular morphology and fine grain size of primary AA2024 particles are achieved after the addition of 2.5 wt.% TiO2 compared to the sample without the addition of nanoparticles composite. In addition, it was found that adding nanoparticles increased energy absorption, and this effect is improved by increasing impact strength by adding nanoparticles, the impact strength increased from 5 j/m2 to 7 j/m2 at 5%. At the same time, the increase of nanoparticles effect decreases the mass losses (increase in wear resistance). With a weight fraction of 5 wt.% TiO2, the alloy exhibits the highest value of hardness.

Elucidating the effect of strain path-dependent crystallographic texture evolution on the electrochemical behavior of nanostructured AA2024 aluminum alloy

This research provides insight into the effect of strain path-dependent texture evolution on the electrochemical behavior of nanostructured AA2024 aluminum alloy in a phosphate buffer solution (pH = 8.3). To achieve this, AA2024 alloy sheets were processed using two methods: accumulative roll bonding (ARB) and cross accumulative roll bonding (CARB), i.e., rotating the sheets 90° around the normal direction (ND) axis between each cycle. The ARB-processed AA2024 alloy exhibited a pancake-shaped structure and included texture components of Copper {112}<111>, Brass {011}<211>, P {110}<221>, and S {123}<634>. Meanwhile, the CARB-processed AA2024 alloy had extremely fine and equiaxed nano-grains (< 100 nm) and texture components of S {123}<634>, Brass {011}<211>, Goss {011}<100>, Rotated Cube {001}<110>, and P {110}<221> after eight cycles. Electrochemical studies demonstrated an increase in corrosion current density due to high imposed strains in the ARB route, which in effect made the conditions of passive layer formation more difficult and lowered the corrosion resistance. Additionally, achieving a more uniform distribution of extremely fine grains and {011} orientation textures such as Brass {011}<211>, Goss {011}<100>, and P {110}<221> texture components in the CARB route, provided ideal conditions for forming oxide passive films with superior protection properties compared to ARB. These unique findings can contribute to the broader application of crystallographic-orientation-dependent electrochemical behavior of alloys in the field of corrosion management.

Parametric analysis of electrical discharge machining on AA6061 with a WC–Cu composite electrode

The AA6061 aluminium alloy surface characteristics presented in this study were obtained after it was machined using die sinking electro discharge machining (EDM) with a composite electrode developed through powder metallurgy. Machining was performed using negative polarity. In order to obtain optimum material removal rate (MRR) and surface roughness (SR), the research has been carried out, and EDM parameters like voltage, current and pulse on time were optimized using the response surface methodology that integrates the central composite design. The parameter interaction effects on EDM machined surface characteristics were studied with the aid of ANOVA. It was determined from model that the regression for MRR and SR were 98.6% and 98.3% respectively, means empirical model is considered sufficient. It was observed that increased MRR and SR were observed in the condition of increased current, but MRR and SR decreased at increased voltage and pulse on time. This could be due to strengthened ionization temperature that increased MRR with acceptable SR. The microstructure of the machine was assessed using microscopic evaluation. The increased current contributed to the formation of a recast layer and debris which hinders the machining process and reduces MRR. The experimental results show that the maximum MRR of 0.087 mg/min and minimum SR of 1.893 µm were achieved. Additionally, the use of WC–Cu composite electrodes led to an increase in hardness from 65 HV to 78 HV in the machined region. It is concluded that WC–Cu composite electrodes typically result in higher hardness, improved MRR and better SR for the AA6061 alloy compared to conventional Cu electrodes.

Center-Punching Mechanical Clinching Process for Aluminum Alloy and Ultra-High-Strength Steel Sheets

In recent years, with the rapid advancement of automotive lightweight technology, the mechanical clinching process between aluminum alloy and ultra-high-strength steel sheets has received extensive attention. However, the low ductility of ultra-high-strength steel sheets often results in conventional mechanical clinching processes producing joints that either fail to establish effective interlocks or cause the steel sheets to fracture. To address this issue, a novel mechanical clinching process is presented, called center-punching mechanical clinching (CPMC). This innovative process employs a method of punching, flanging, and bulging gradation to achieve the mechanical clinching of aluminum alloy and ultra-high-strength steel sheets in a single step. In order to determine the effects of different parameters on the quality and strength of the joint, an experimental study was carried out for various die depths and diameters based on the condition of constant punch size. Based on tensile and shear tests, the static strength and failure modes of CPMC joints were analyzed. The results indicated that the CPMC process significantly enhances the connectivity of joints for AA5052 aluminum alloy and DP980 ultra-high-strength steel. Optimal tensile and shear strengths of 1264 and 2249 N, respectively, were achieved at a die depth of 2.2 mm and a diameter of 10.4 mm. The CPMC process provides new ideas for the mechanical clinching of aluminum alloy and ultra-high-strength steels.

Analyzing the Influence of Titanium Content in 5087 Aluminum Filler Wires on Metal Inert Gas Welding Joints of AA5083 Alloy

As the demand for lightweight structures in the transportation industry continues to rise, AA5083 aluminum alloy has become increasingly prominent due to its superior corrosion resistance and weldability. To facilitate the production of high-quality, intricate AA5083 components, 5087 aluminum filler wire is commonly utilized in metal inert gas (MIG) welding processes for industrial applications. The optimization of filler wire composition is critical to enhancing the mechanical properties of AA5083 MIG-welded joints. This study investigates the effects of modifying 5087 aluminum filler wires with different titanium (Ti) contents on the microstructure and weldability of AA5083 alloy plates using MIG welding. The influence of Ti contents was systematically analyzed through comprehensive characterization techniques. The findings reveal that the constitutional supercooling induced by the Ti element and the formation of Al3Ti facilitate the heterogeneous nucleation of α(Al), thereby promoting grain refinement. When the Ti content of 5087 filler wire is 0.1 wt.%, the grain size of the weld center was 78.48 μm. This microstructural enhancement results in the improved ductility of the AA5083 MIG-welded joints, with a maximum elongation of 16.64% achieved at 0.1 wt.% Ti addition. The hardness of the joints was the lowest in the weld center zone. This study provides critical insights into the role of Ti content in MIG welding and contributes to the advancement of high-performance filler wire formulations.

Investigation of an L-Shaped Cross-Sectioned AA6061 Aluminum Alloy Ring via Extrusion and Self-Bending Integral Processing Technology

Investigation of an L-Shaped Cross-Sectioned AA6061 Aluminum Alloy Ring via Extrusion and Self-Bending Integral Processing Technology

Coupling Taguchi experimental designs with deep adaptive learning enhanced AI process models for experimental cost savings in manufacturing process development

The Aluminum alloy AA7075 workpiece material is observed under dry finishing turning operation. This work is an investigation reporting promising potential of deep adaptive learning enhanced artificial intelligence process models for L18 (6133) Taguchi orthogonal array experiments and major cost saving potential in machining process optimization. Six different tool inserts are used as categorical parameter along with three continuous operational parameters i.e., depth of cut, feed rate and cutting speed to study the effect of these parameters on workpiece surface roughness and tool life. The data obtained from special L18 (6133) orthogonal array experimental design in dry finishing turning process is used to train AI models. Multi-layer perceptron based artificial neural networks (MLP-ANNs), support vector machines (SVMs) and decision trees are compared for better understanding ability of low resolution experimental design. The AI models can be used with low resolution experimental design to obtain causal relationships between input and output variables. The best performing operational input ranges are identified for output parameters. AI-response surfaces indicate different tool life behavior for alloy based coated tool inserts and non-alloy based coated tool inserts. The AI-Taguchi hybrid modelling and optimization technique helped in achieving 26% of experimental savings (obtaining causal relation with 26% less number of experiments) compared to conventional Taguchi design combined with two screened factors three levels full factorial experimentation.

Investigation on effects of nano-reinforcement on the mechanical properties, fatigue, and microstructural analysis of dissimilar AA6061- Mg AZ31B weld joints

Weld joints have been subject to substantial improvement in mechanical durability and wear resistance in recent years. This research work challenge can be answered by incorporating nano-materials into the weld zone. Mechanical and metallurgical aspects of friction stir welded (FSW) butt joints made of AA6061 aluminum and Mg AZ31B alloys have been examined in this work, both with and without the use of naturally derived biochar nanoparticles. The biochar particle was extracted from rice husk. Throughout the whole weld joint manufacturing process, a tool with a rotational speed of 1400 rpm, a welding speed of 40 mm min−1, and a tapered pin profiled tool were employed. During the joint fabrication process, the constant axial load of 7 kN, plunge depth of 0.2 mm, and constant dwell time of 0.3 s were also maintained. In order to improve the mechanical attributes of the weld joints, different wt% of biochar such as 1%, 2%, and 3%, were applied at the interface region of the weld joints. The experimental results revealed that the percentage of reinforced nano-materials plays a significant effect in improving the weld joint qualities. The testing results of reinforced friction stir-welded joint qualities were compared to those of simple friction stir welded joints made without and with adding the nanoparticles. The best results were obtained when 2 wt% of biochar particles was added to the weld interface region. The presence of biochar nano-particles, in addition to their contribution to increased grain refinement in the weld nugget region, was also seen in the region. It was discovered that the event distribution of particles at the nugget zone significantly enhanced the mechanical and wear resistance qualities of the weld joints that were manufactured. The optical microscope was used to analyze the microstructures in the weld nugget region, and a scanning electron microscope (SEM) was utilized to examine the fracture analysis of the tensile samples. The presence of 2 wt% biochar particles in the weld nugget region resulted in a considerable increase in the mechanical characteristics of the weld connections. The ultimate tensile strength, hardness, and yield strength of the weld nugget results 197 MPa, 173 HV, 163 MPa. Overall, when compared to the qualities of the base material and plain weld joints. The mechanical properties and wear resistance of the weld joints have improved significantly. When biochar particles were used as reinforcement particles during the fabrication phase of the joint, a mechanism for pinning was observed in the weld microstructure.

Unveiling the mechanical and microstructural properties of SiC reinforced aluminum wires recycled from scraps by friction stir extrusion

Friction Stir Extrusion (FSE) has been proven as an effective solid-state process to directly recycle metal chips into high-quality wires/rods/tubes. However, the demand for Al-based composite wires with enhanced properties is substantial, and achieving a uniform distribution of the strengthening phase within the composite wire by establishing a robust metal/ceramic interface remains a significant challenge. In this study, AA6082 Aluminum alloy wires reinforced with 12.5 vol% SiC particles, exhibiting homogeneous particle distribution and superior mechanical properties, were successfully produced through the FSE technique. The investigation focused on examining the influence of processing parameters and the addition of SiC reinforcement on the microstructure and mechanical characteristics of the extruded wires. Scanning electron microscopy (SEM), Electron Backscatter Diffraction (EBSD), together with microhardness, bending, and tensile tests, were used to comprehensively analyze the resulting properties. The findings demonstrate a substantial enhancement in the wires' mechanical properties due to the SiC particles. Both tool rotation and tool force were varied during the experimental campaign. Notably, the reduction in porosity and grain refinement resulted in a 12.78 % increase in tensile strength and an 18.6 % improvement in microhardness compared to Al 6082 alloy extruded wires. Grain orientation analysis revealed a fully recrystallized microstructure with a weak texture. Furthermore, the study evaluated power consumption and surface roughness while assessing the feasibility of deposition, thereby highlighting the potential application of this technique in advanced additive manufacturing processes.

Nanoparticle-enabled additive manufacturing of high strength 6061 aluminum alloy via Laser Powder Bed Fusion

Wrought aluminum alloy AA6061 is widely used in automotive, aerospace, and other industries due to its good properties, including high strength, excellent corrosion resistance, and good weldability. However, when using Laser Powder Bed Fusion (LPBF) for AA6061, hot cracking becomes a serious problem. In this work, AA6061 powder with internally dispersed nanoparticles has been adopted in a LPBF process. Through optimization of printing parameters, components with minimal porosity (less than 0.5 %) have been successfully produced without cracks. Additionally, by employing a chessboard printing strategy to create finely detailed cellular and grain structures, we have achieved significantly enhanced mechanical properties in its as-printed state for AA6061. These components exhibit an impressive yield strength (YS) of 233 MPa and ultimate tensile strength (UTS) of 310 MPa while maintaining a ductility of approximately 10 %. This performance surpasses that of commercial AA6061 and other Al-Si alloys, establishing it as a high-strength material suitable for various applications.

Three-dimensional simulation of finite element ultrasonic welding of aluminum alloy AA-6061

Three-dimensional simulation of finite element ultrasonic welding of aluminum alloy AA-6061

Characteristics of Dissimilar AA5083 and AA7050 Aluminium Alloys Friction Stir Butt Welded with Different Tool Axis Offsets

Characteristics of Dissimilar AA5083 and AA7050 Aluminium Alloys Friction Stir Butt Welded with Different Tool Axis Offsets

Investigation of Weldability in Friction Stir Welding of Aluminum Alloys AA5754 and AA2024

Investigation of Weldability in Friction Stir Welding of Aluminum Alloys AA5754 and AA2024

Effect of underwater friction stir welding parameters on AA5754 alloy joints: experimental studies

The water as a welding environment may generate serious technological and metallurgical problems but in certain cases, the physicochemical properties of water can be used effectively, e.g., to impart the specific properties of welded materials. The purpose of the work was verification of effectiveness of the water cooling of aluminium alloy AA5754 for various sets of technological parameters of underwater friction stir welding (UFSW). For the joints performed with the range of parameters of rotational speed: 475–925 rpm and welding speed: 47.5–95 mm/min, the following examinations were carried out: visual tests, radiographic tests, static tensile test, fractography (SEM, scanning electron microscope) analysis, and surface texture analysis performed with 3D measurement system. All of the joints were characterized with some amount of flash. Besides, depending on the values of selected parameters, the defects arising from inadequate stirring were found—tunnel defects and melting. The best appearance of the joint was obtained for the set of parameters of 925 rpm and 47.5 mm/min. The samples of the same joint were found to be of the highest mechanical properties—ultimate tensile strength (UTS) of 194 MPa and elongation (A) of 9.2%. The results were confirmed by the fractography analysis, which in this case indicated the ductile fracture mode. Dynamic plastic behaviour strongly depends on the process parameter values, which was reflected in the results of surface texture analysis. The parameter selection resulted in significant changes in the roughness results (from 8 to 14.2 µm depending on the sample) as well as the flow ring distance of the weld (from 20 to 50 µm depending on the sample).