Papers by Keyword: AA6082

Abstract: Recycling aluminum chips remains a major challenge in aluminum manufacturing because it is difficult to retain the original quality alloy properties while reducing the carbon footprint and ensuring a sustainable process. This work investigates the microstructural evolution and bonding quality of compacted AA6082 chips processed through friction extrusion/consolidation. The residual material left inside the extrusion container after processing at a high extrusion ratio was analyzed using SEM, EDS, and EBSD to understand bonding mechanisms and microstructure evolution in front of the die. The SEM results show that voids are still present between the chips in the initial compacted material which already shows bonding, while these voids are reducing towards the die interface, particularly related to the present severe plastic deformation. EDS analysis confirms the presence of Al (Fe,Mn)Si intermetallic particles, which break and disperse in the matrix because of shear deformation due to die rotation. EBSD analysis reveals that grains are coarser near the base material, and subdivisions of grains near the die interface are significant because of continuous dynamic recrystallization.

Abstract: This study examines the forging process of an aluminum upper control arm for automotive applications. To address the geometric complexity and forming challenges, a multi-step forging route, comprising of roll forging, two-stage bending, pre-forging, and final forging, is developed. Finite element analysis (FEA) using DEFORM-3D software is employed to optimize key forming process parameters in the pre‑forging stage. The response surface methodology (RSM), combined with the Box–Behnken design, is utilized to construct predictive models and identify optimal parameter combinations. A successful forged upper control arm is subsequently produced using these optimized forming parameters. The findings demonstrate that integrating FEA with statistical process optimization strengthens the predictive accuracy of the process design and supports defect‑free forging of AA6082 upper control arms.

Abstract: In Friction Stir Welding (FSW) tool geometry plays a critical role in governing heat generation, material flow, and microstructural evolution within the weld. In this study, the feasibility and performance of FSW tools manufactured by Laser Powder Bed Fusion (L-PBF) are experimentally and numerically investigated. A non-conventional FSW tool produced in AISI 316L by L-PBF was designed and compared with a conventional machined steel tool in the welding of AA6082-T6 sheets performed using already optimized process parameters. This was followed by tensile testing and macro-and micro-hardness measurements, and a punctual microstructural analysis. In addition, a 3D thermo-mechanical finite element model was employed to forecast and analyze the temperature distribution, the effective strain and the overall material flow. The results show that the tool manufactured using L-PBF enables FSW joints to achieve mechanical properties and welding efficiency similar to those of the standard tool. Finite Elements Models (FEM), in good agreement with experimental results, show that the geometry of the additive tool promotes greater plastic deformation and lower peak temperatures, confirming both the validity of the model and the suitability of L-PBF for the advanced design of FSW tools.

Abstract: In hot extrusion of light alloys, nitrogen cooling has become a strategic solution to mitigate thermal issues from high deformation rates and frictional heating, improving surface quality, extrusion speed, and die life. However, current cooling system designs remain largely empirical, and the limited use of predictive modeling and experimental monitoring often leads to inconsistent evaluations. This work proposes a dual-step procedure for transient numerical analysis of multiple billets with nitrogen cooling. First, a 1D numerical model of nitrogen cooling is simulated in a simplified environment reproducing extrusion thermal conditions, requiring negligible computational time. The resulting heat transfer coefficient (HTC) and nitrogen temperature are then integrated into the process model, implemented in Qform code, as additional boundary conditions. This approach enables the fully 3D extrusion model to account for nitrogen cooling effects not only on thermal gradients but also on aluminium flow and die resistance. A porthole die with three tube-shaped openings for hollow profile extrusion was experimentally tested under cooled and uncooled conditions, with thermal behaviour monitored by eleven thermocouples within the tooling set. Experimental–numerical comparison confirmed the advantages of numerical simulation for cooling channel design and the limitations of experience-based approaches.

Abstract: The Extrusion Benchmark 2023 was focused on the evaluation of different die design strategies for the manufacturing of AA6082 hollow tubes (40 mm external diameter and 4 mm thickness) through a porthole die with 3 openings. The extrusion process was monitored in industrial environment in terms of press load, profiles speed, profiles exit temperature, and die temperatures under different processing conditions (air quenching, water quenching, nitrogen die cooling). Extruded profiles were then analyzed in terms of seam weld quality, charge weld extension and microstructure evolution for both air/water quench and presence/absence of nitrogen cooling. The results of the study are aimed at validating FEM simulation outputs in the context of the International Conference on Extrusion and Benchmark (ICEB).

Abstract: Materials characterization and the knowledge of their elastic-plastic behavior are of fundamental importance for the design of industrial manufacturing processes. Nowadays, FEM simulation is the main tool used to optimize product quality and minimize scraps, and the numerical codes have evolved over the years to obtain accurate solutions with reduced computational times. Nevertheless, in order to perform reliable simulations, it is necessary to include accurate modeling of the material flow stress. Hot torsion is a powerful method for the characterization of the material flow stress because, tests can be carried out at constant speeds and temperatures, reaching large strain values, and thus getting over the limits of compression and tensile tests. In this paper the hot torsion characterization applied to AA6082 alloy is presented: tests were performed with equivalent strain rates of 0.01, 0.1, 1, and 10 s^-1, in the temperature range from 440 to 550 °C (from 713.15 to 823.15 K). The results are presented in terms of equivalent stress vs equivalent strain. Finally, the material flow stress curve was predicted by the Hyperbolic sine model and Hensel-Spittel law, and the material parameters A, m_1-9 are provided for the temperature expressed in °C and K.

Abstract: This review paper emphasizes joining aluminum and its alloys by using conventional joining methods, where the formation of defects is occurred in weld joints. The defects are porosity, cracks, hole formation, residual stress, distortion are observed in traditional weld joints. To overcome these defects in welds, The Welding Institute UK has developed a green welding process such as friction stir welding (FSW). The joints of aluminum and its alloys exhibit different FSW characteristics depends on the tool rotational speed and traverse speed. Various aluminum alloys exhibit different strengths for different tool rotational speeds. The main reason for variations in microhardness is the quantity of heat input and enough heat should be supplied to obtain sound joints. Therefore, there is still lack of studies that need to be carried out to optimize the quantity of heat input needed to achieve improved weld strength and joint efficiency. In addition, FSW process needs to be integrated with artificial intelligence tools to monitor the process online.

Abstract: The properties of anodized aluminum, and wear resistance in particular, are of high interest for the scientific community. In this study, discs of AA6082 were subjected to a peculiar hard anodizing process leading to anodized samples having different thicknesses. In order to investigate the wear mechanism of samples, unidirectional tribological tests were performed against alumina balls (corundum) under different loading conditions. Surface and microstructure of all the samples were characterized before and after the tribological tests, using different characterization techniques. The tribological tests showed remarkable differences in the friction coefficient and wear behavior of the anodized AA6082 samples, related to the microstructure modifications and to the specific applied sliding conditions.

Abstract: In the present work, laser weld-brazing experiments were performed to produce aluminum to galvanized steel joints in lap and flange configuration. Tests were carried out using Al-12 % Si eutectic filler wire for joining of AA6082 -T6 with galvanized steel with varying laser power and keeping other parameters (wire feed and laser scan speed) constant. Microstructural characteristics of the laser brazed joints, studied by SEM, revealed cast structure in the brazed zone. Intermetallic formed at the steel interface was non-uniform. From the hardness results, it was noted that the brazed region exhibits lower hardness compared to the base material. The wetting length was improved with increasing filler wire rate, which in turn improved the strength of the brazed joint in both the configuration (lap and flange). At 4 kW laser power, flange configuration sample has failed in AA6082 whereas, in case lap joint, failed in the heat affected zone of AA6082.

Abstract: The development of simulation tools for bridging different scales are essential for understanding complex joining processes. For precipitation hardening, the Kampmann-Wagner numerical model (KWN) is an important method to account for non-isothermal second phase precipitation. This model allows to describe nucleation, growth and coarsening of precipitation hardened aluminum alloys based on a size distribution for every phase which produces precipitations. In particular, this work investigates the performance of a KWN model by [1-3] for Al-Mg-Si-alloys. The model is compared against experimental data from isothermal heat treatments taken partially from [2]. Additionally, the model is used for investigation of the precipitation kinetics for a laser beam welding process, illustrating the time-dependent development of the different parameters related to the precipitation kinetics and the resulting yield strength.