Aluminum Alloy Research Articles

Effect of shot peening on microstructural features, residual stress behavior, and hardness of aluminum alloy 2014

Abstract The current study investigates the effect of shot peening on the microstructural features, residual stress distribution, and surface hardness of aluminum alloy 2014, which is essential for applications in aerospace, automobile, and structural components requiring improved fatigue life and wear resistance. Microstructural analysis reveals significant grain refinement (6.6 µm) in the treated specimen and fragmentation of Al₂Cu precipitates, reducing their size from 1.9 µm in the untreated specimen to 0.6 µm in the treated specimen. X-ray diffraction confirms grain refinement and increased dislocation density in the shot-peened alloy, evidenced by enhanced peak intensities and slight broadening. Residual stress measurements show a shift from near-neutral stresses in the untreated alloy to compressive stresses in the shot-peened layer, with a peak stress of -313.1 MPa at the surface, transitioning to tensile stresses at deeper layers. Surface hardness analysis shows a substantial increase to 131.5 HV near the surface, compared to 115 HV in the untreated specimen, due to work hardening, grain refinement, and induced compressive stresses.

Finite element and experimental study on ultrasonic-assisted TIG welding of 5083 aluminum alloy

Finite element and experimental study on ultrasonic-assisted TIG welding of 5083 aluminum alloy

Parametric optimization of abrasive waterjet machining for aluminum 7075/boron carbide/zirconium silicate hybrid composites

In the present work, an attempt was made to study the machining characteristics of Hybrid Metal Matrix Composites (HMMCs) using Abrasive Waterjet Machining (AWJM). For preparing the composites, Aluminum alloy 7075 is cast with boron carbide (B4C) and zirconium silicate (ZrSiO4) reinforcement by the method of stir casting. Experimental investigation of the machining parameters on Depth of Cut (DoC), Material Removal Rate (MRR), and Surface Roughness (SR) was done. The independent parameters include Abrasive Mesh Size (AMS), Abrasive Flow Rate (AFR), Water Jet Pressure (WJP), and Traverse Rate (TR). The results of experiments reveal that low TRs increase SR, while short AMSs, high flow rates, and large WJPs increase DoC and MRR. Surface maps made by SEM exposed information about the surface texturing and the material removal processes. It was found that the optimal DoC was achieved at an AMS 80#, AMS of 340 g/min, WJP of 200 MPa, and TR of 60 mm/min for both unreinforced Al and the composite of Al + 5% B4C + 5% ZrSiO4. The results enable the development of proper AWJM procedures for HMMCs to ensure better surface finish and workability. From the experiments, it was observed that while smaller mesh sizes and greater AFR will improve MRR and DoC, it can at the same time have a negative effect on the overall performance of Kerf Taper angle (KT) and Surface Roughness (SR).

Tribological properties study and prediction of QBe2 beryllium bronze and 7075-T6 aluminum alloys based on machine learning under mixed lubrication

Tribological properties of materials exhibit complex and non-linear correlation with working conditions under mixed lubrication. Selecting an appropriate data-driven method to predict tribological properties is important for accelerating material design and preparation. This paper investigates the tribological performance and wear mechanisms of QBe2 beryllium bronze and 7075-T6 aluminum alloy pairs under grease lubrication by using pin-on-disk friction and wear tests. The tribological performance under different conditions is further predicted using four machine learning algorithms: K-nearest Neighbors (KNN), Support Vector Machine (SVM), Artificial Neural Network (ANN), and Random Forest (RF). The experimental and machine learning results both show that reciprocating frequency has the most significant influence. The dominant wear mechanisms include ploughing and adhesive wear. Furthermore, among the four machine learning models, SVM model performs the best in predicting tribological properties of QBe2 beryllium bronze and 7075-T6 aluminum alloy under mixed lubrication.

Effect of Tool Shoulder Profile on Grain and Texture Development in the Weld Interface Zone of Friction-Stir-Welded Dissimilar AA2024/AA7075 Joints

Friction-stir-welded dissimilar AA2024/AA7075 joints have an apparent influence on grain and texture development at the weld interface due to differences in physical and chemical properties between the two aluminum alloys. In this work, the effect of tool shoulder profile on grain structure and texture evolution in the center interface zone (CIZ) and bottom interface zone (BIZ) of dissimilar AA2024/AA7075 joints were quantitatively studied by electron back-scattering diffraction (EBSD). The results indicate that abundant fine and coarse equiaxial grains are produced in the CIZ and BIZ of the joints produced with a concentric circle shoulder (CCS) and three-helix shoulder (THS), and the average grain size of the BIZ is lower than that of the CIZ for the same CCS or THS joint. A higher degree of recrystallization occurs in the CIZ of the joint with a CCS than that of the joint with a THS, while a similar degree of recrystallization is presented in the BIZ of the two joints. For the distribution of local misorientation angle between the two sides of the interface in the same CCS or THS joint, the CIZ manifests relatively uniform behavior, while the BIZ presents the characteristics of uneven distribution. Tool shoulder profile has a significant impact on the texture components at the weld interface, which results in different types of shear textures generated in the CIZ and BIZ of the two joints. It is beneficial to make out the microstructural evolution mechanism at the weld interface in dissimilar FSW joints for engineering applications in this study.

Effect of periodic overloads on the ∆K threshold estimates in an aluminum alloy

Effect of periodic overloads on the ∆K threshold estimates in an aluminum alloy

Influence of Heat Treatment on Properties and Microstructure of EN AW-6082 Aluminium Alloy Drawpieces After Single-Point Incremental Sheet Forming

An EN AW-6082 aluminium alloy is one of the 6000 series aluminium alloys with the highest strength properties. Due to its favourable strength-to-density ratio, it is used, among others, in the automotive and aviation applications. It is also characterised by good formability, especially in the annealed condition. This article presents the results of investigations on the possibility of forming a 2 mm thick EN AW-6082 alloy sheet using the incremental sheet-forming process depending on the material condition (O, W, T4, T6). The microstructure of the material after heat treatment and the mechanical properties of the workpiece material in as-received state, as well as after forming, were examined. Additionally, for selected cases, additional heat treatment of the drawpieces was performed to improve their mechanical strength. The values of the limit-forming angle were determined for the materials tested. The values of this angle varied from 69° for the annealed sheet to 61° for the material in the T6 condition. The highest yield stress (YS) and ultimate tensile strength (UTS) were found for sheets (YS = 305 MPs and UTS = 324 MPa) and the artificially aged drawpieces (YS = 333 MPa and UTS = 390 MPa). Additional ageing after incremental sheet forming resulted in an increase in strength properties compared to drawpieces without additional heat treatment only in the case of drawpieces made of sheet metal after the solutionising and in T4 condition.

Experimental Investigation of Low‐Cycle Corrosion Fatigue Behavior of AA5059 Aluminum Alloy in Air and 3.5% NaCl Solution Environments

ABSTRACTThe shipbuilding industry is increasingly adopting aluminum alloys like AA5059 over traditional steel alloys to achieve lighter structures, enhanced environmental protection, and improved energy efficiency. Ship structures are frequently subjected to fatigue loading from combined wave‐induced stresses and corrosive effects. This study investigates the low‐cycle fatigue (LCF) behavior of AA5059 aluminum alloy in both air and a 3.5% NaCl solution to assess the impact of corrosion on fatigue life. LCF tests were conducted at strain amplitudes of ΔεT/2 = 0.3%–0.7%. The findings indicate a marked reduction in fatigue life in the NaCl solution compared with air, regardless of strain amplitude. Back (σb), effective (σeff) stresses were assessed using Dickson's approach, showing reduced back stress and increased effective stress in 3.5% NaCl, indicating diminished hardening and enhanced plastic deformation. Corrosion was observed to enhance plastic strain energy density (PSED), with specimens exhibiting massing behavior in air and non‐massing behavior in the corrosive environment. Fractographic analysis revealed corrosion pits, oxide formations, and secondary cracks in the crack initiation (CI), crack propagation (CP), and final fracture (FF) regions in NaCl. These findings on the low‐cycle corrosion fatigue performance of AA5059 provide valuable guidance for its application in shipbuilding, particularly in corrosive marine environments.

Mechanical and corrosion characteristics of low-density polyethylene reinforced with aluminum alloy AA6065 honeycomb structure

Mechanical and corrosion characteristics of low-density polyethylene reinforced with aluminum alloy AA6065 honeycomb structure

Superhydrophobic Coatings Based on PMMA-Siloxane-Silica and Modified Silica Nanoparticles Deposited on AA2024-T3

The study aimed to develop a superhydrophobic coating on the aluminium alloy 2024-T3 surface. The desired surface roughness and low surface energy were achieved with SiO2 nanoparticles, synthesised via the Stöber method and modified with alkyl silane (AS) or perfluoroalkyl silane (FAS). To enhance particle adhesion to the alloy substrate, nanoparticles were incorporated into a hybrid sol–gel coating composed of tetraethyl orthosilicate, methyl methacrylate, and 3-methacryloxypropyl trimethoxysilane. The coated substrates were characterised using field emission scanning and transmission electron microscopy with energy-dispersive spectroscopy for surface topography, nanoparticle size distribution, composition, and coating thickness. The corrosion resistance of the coatings on AA2024-T3 was evaluated in a 0.1 M NaCl solution using electrochemical impedance spectroscopy. The synthesised SiO2 nanoparticles had an average size between 25 and 35 nm. The water contact angles on coated aluminium surfaces reached 135° for SiO2 + AS and 151° for SiO2 + FAS. SiO2 + FAS, indicating superhydrophobic properties, showed the most uniform surface with the most consistent size distribution of the SiO2 nanoparticles. Incorporation of nanoparticles into the hybrid sol–gel coating further improved particle adhesion. The ~2 µm-thick coating also demonstrated efficient barrier properties, significantly enhancing corrosion resistance for over two months under the test conditions.

Study on material J-C parameter fitting and cushioning characteristics of 2A12 aluminum honeycomb sandwich under impact environment

To address the negative impact of excessive impact forces during the penetration of space debris by harpoon attachment devices, causing damage to rear electronic components, research has been conducted on the buffering and energy absorption effects of 2A12 aluminum honeycomb. A simulation model for aluminum honeycomb impact crushing was established through 2A12 aluminum alloy quasi-static tests, SHPB dynamic compression tests, and 2A12 aluminum honeycomb quasi-static compression tests. The study investigated the effect of aluminum honeycomb on impact response accelerations in harpoon attachment device impact tests. The research results show that at launch velocities of 29.2 m/s and 29.6 m/s, the peak impact response accelerations were 866.56 g and 880.75 g respectively, with simulation results of 841.31 g and 868.29 g, indicating small errors of 2.91% and 1.41% respectively, verifying the correctness of the impact crushing simulation model. Further simulation analysis showed that the peak impact response accelerations without aluminum honeycomb buffering were 1549.21 g and 1588.14 g respectively. Compared with test results with aluminum honeycomb buffering, the peak impact response accelerations decreased by 682.65 g and 707.39 g respectively; compared with simulation results with buffering, the peak impact response accelerations decreased by 707.9 g and 719.85 g respectively. This demonstrates that using 2A12 aluminum honeycomb as a buffering structure for harpoon attachment devices effectively enhances energy absorption.

The Influence of Step Deviation and Squeeze Force on the Mechanical Properties of Aluminum Alloy Riveted Joints

The Influence of Step Deviation and Squeeze Force on the Mechanical Properties of Aluminum Alloy Riveted Joints

Effect of quenching medium, solution treatment, and aging parameters on mechanical properties of Aluminum alloy 6061

Effect of quenching medium, solution treatment, and aging parameters on mechanical properties of Aluminum alloy 6061

Formability Assessment Based on Q-Value for Optimizing the Deep Drawing Process of Automotive Parts Made from Aluminum Alloys Sheet

This paper presents a novel Q-value-based formability assessment for optimizing deep drawing processes. The Q-value, derived from thinning limit diagrams (TLDs), uses offset thinning and wrinkling limit curves to define severity levels. It is calculated by summing the product of Pascal’s triangle weighting factors and normalized element counts within each severity level. The effectiveness of this Q-value assessment was demonstrated using experimentally validated finite element analysis (FEA) to optimize blank size, tool geometry, and drawbead design (male bead height and contra-bead radius) for a deep-drawn AA5754-O automotive fuel tank. Validation of FEA results with experimental thickness measurements showed that the Barlat and Lian 1989 yield criterion provided higher accuracy than Hill’s 1948 model. An optimal condition, determined using the Q-value, consists of a 430 mm × 525 mm blank formed by a redesigned tool cooperated with optimized semi-circular drawbead geometries, achieving experimental significant formability improvements by minimizing wrinkling and thinning. During optimization, this study revealed a significant interaction between blank width and length, which influenced formability. Side-wall wrinkles were attributed to insufficient tool support for the blank during forming and were relieved through tool redesign. Furthermore, increasing the male drawbead height effectively reduced wrinkling but led to increased thinning, whereas increasing the contra-bead radius had the opposite effect.

Enhancing Ω Phase Thermal Stability in Al Alloys through Interstitial Ordering.

Scandium (Sc) can orderly occupy interstitial sites within the Ω phase of aluminum alloys, forming a new phase that significantly enhances the thermal stability of the alloy. However, Sc is relatively expensive and rare. In this work, we employ first-principles calculations to delve into the physical essence interstitial ordering of Sc in enhancing thermal stability at the electronic level, thereby revealing the crucial factors responsible for this improvement. By computationally screening all potential metallic elements across the periodic table, we uncover that, in addition to Sc, a diverse range of elements including lithium (Li), calcium (Ca), strontium (Sr), and some of rare earth elements (Sm, Ce, Y), possess the potential to contribute to thermal stability enhancement through interstitial ordering mechanisms in aluminum alloys. This study deepens our understanding of microstructural thermal stability and offers novel strategies for designing improved thermally stable Al alloys.

Accelerated development of multi-component alloys in discrete design space using Bayesian multi-objective optimisation

Abstract Bayesian optimisation (BO) protocols grounded in active learning (AL) principles have gained significant recognition for their ability to efficiently optimize black-box objective functions. This capability is critical for advancing autonomous and high-throughput materials design and discovery processes. However, the application of these protocols in materials science, particularly in the design of novel alloys with multiple targeted properties, remains constrained by computational complexity and the absence of reliable and robust acquisition functions for multiobjective optimisation. Recent advancements have demonstrated that expected hypervolume-based geometrical acquisition functions outperform other multiobjective optimisation algorithms, such as Thompson Sampling Efficient Multiobjective optimisation and pareto efficient global optimisation (parEGO), in both performance and speed. This study evaluates several leading multiobjective BO acquisition functions–namely, parallel expected hypervolume improvement (qEHVI), noisy qEHVI, parallel parEGO, and parallel noisy parEGO (qNparEGO)–in optimizing the physical properties of multi-component alloys. Our findings highlight the superior performance of the qEHVI acquisition function in identifying the optimal Pareto front across 1-, 2-, and 3-objective aluminum alloy optimisation problems, all within a constrained evaluation budget and reasonable computational cost. Furthermore, we explore the impact of various surrogate model optimisation methods from both computational cost and efficiency perspectives. Finally, we demonstrate the effectiveness of a pool-based AL protocol in expediting the discovery process by executing multiple computational and experimental campaigns in each iteration. This approach is particularly advantageous for deployment in massively parallel high-throughput synthesis facilities and advanced computing architectures.

Surface state study of the pre-treatment process for electroless plated aluminum alloys for EP mandrels

Surface state study of the pre-treatment process for electroless plated aluminum alloys for EP mandrels

Residual Stress in Friction Stir Welding of Dissimilar Aluminum Alloys: A Parametric Study

Welding-induced residual stress has the capacity to significantly compromise the integrity of mechanical components. Its minimization therefore plays a critical role in the selection of process parameters during the welding process. Friction stir welding is a useful joining technique to weld many materials that are not amenable to the traditional welding techniques. Using a sequentially coupled thermomechanical three-dimensional finite element simulation, this work aimed to quantitatively evaluate the influence of the tool rotational and traverse speeds on the generation of residual stress in the friction stir welding of dissimilar aluminum alloys AA2024−T3 and AA5086−O. The model was validated using established experimental and numerical results. The procedure entailed an initial thermal analysis, the results of which were superposed on a mechanical model to determine the distribution of the residual stress across the welded alloy. The results showed that longitudinal residual stress was dominant as compared to lateral stress. It was also demonstrated that, although the tool rotational speed and the tool traverse speed both affected the post-weld temperature distribution and consequently the longitudinal residual stress, the influence of the former was more substantial. Furthermore, the peak values of the residual stress were found on the retreating side (AA5086−O), making it more critical for the selection of welding process parameters.

DACNN based predicting tensile strength of friction stir welded aluminium alloy joints

DACNN based predicting tensile strength of friction stir welded aluminium alloy joints

Recent progress in wire-arc and wire-laser directed energy deposition (DED) of titanium and aluminium alloys

Recent progress in wire-arc and wire-laser directed energy deposition (DED) of titanium and aluminium alloys