Papers by Keyword: AA3003

Abstract: Microstructural evolution during D.C. casting and subsequent homogenization of non-heat-treatable aluminium alloys involves complex phenomena, including micro-segregation of alloying elements and intermetallic phase selection during solidification as well as phase transformations of both primary (constituents - intergranular) and secondary (dispersoids - intragranular) intermetallic phases. In this study, we simulated the microstructural evolution of AA3003 using a CALPHAD-based modelling framework implemented in ThermoCalc®. The framework integrates a Scheil-Gulliver solidification model coupled with a 1-D micro-segregation alleviation and diffusional phase transformation model (DICTRA®) and a Kampmann-Wagner Numerical (KWN) model for dispersoid precipitation (TC-PRISMA®). According to this approach, the development of a robust computational methodology is aimed at accurately predicting the influence of homogenization cycles on dispersoid precipitation, which in turn affects recrystallization behaviour via the well-known Smith-Zener drag phenomenon. Additionally, these CALPHAD-based simulations facilitate the assessment of impurity content effects on dispersoid precipitation, considering the increasing use of scrap in the fabrication of non-heat-treatable aluminium alloys. Furthermore, they provide precise estimates of Smith-Zener pinning forces as inputs for downstream mesoscale full-field process models, contributing to a holistic through-process modelling approach.

Abstract: Two different conditions were used to study the effect of homogenization on extrusion texture and microstructure evolution in AA3003. The first condition considered homogenization for 8 h at 500°C to obtain a high density of dispersoids and the other condition was homogenized for 24 h at 600°C to produce a sample with a very low density of dispersoids. After uniaxial extrusion at 400°C with a speed of 32 mm/s and an extrusion ratio of 70:1, the material with a high density of dispersoids formed <001> and <111> double fibre texture in the centre of extrusion rod and a smeared texture from <011> to <111> near the surface. For the material without dispersoids, only <001> texture fibre is observed in the centre of extrusion rod and a strong <011> fibre is observed near the surface.

Abstract: Hermetic sealing is essential for long cycle life and calendar life of Lithium ion cells. Ingress of moisture and leaking of electrolyte in Lithium ion cells deteriorates the electrochemical performance. Nickel coated mild steel, Stainless steel, Aluminium and its alloys are generally used as case material. Pure Aluminium and Aluminium alloys are used to improve energy density of Lithium ion cells. High heat input is required for aluminium to obtain a sound weld because of the high thermal conductivity of the Aluminium. High heat input results in increased heat affected zone (HAZ) and transfer of heat into internal components during welding. Laser Beam Welding (LBW) results in very narrow heat affected zone (HAZ) and it is possible to have dissimilar metal welding. In the present work, experimental studies conducted to optimise the laser beam welding parameters for welding of Li-ion AA3003 cell case to lid without defects viz porosity and required weld strength. Hermeticity and strength of the weld bead were analysed in detail to ensure the adequacy of the process. It has been demonstrated that laser beam welding is a viable process for joining of cell case to its cover.

Abstract: Aluminium alloy cans are generally used as containers for electrochemical energy systems like capacitors and advanced batteries. Packing efficiency of batteries depends upon their configuration. Containers in prismatic, cylindrical and elliptic-cylindrical shapes are generally used for battery applications. Elliptic-cylindrical shape has the advantage of better heat dissipation and good packing efficiency in battery assembly. Safety device to be provided in the cans requires material in the minimum half hard (H14) condition. In the present work, ellipsoidal cans of Al-Mn alloy were successfully realised by impact extrusion process. Mechanical properties of the cans were analysed through to ensure the adequacy of the process and it has been demonstrated that impact extrusion is a viable process for making cans for batteries with required mechanical properties, for the can in total and for the safety device in particular.

Abstract: This study examines the recovery behaviour of the inter-alloy region between a core AA6XXX clad with AA3003 after 72% rolling reduction. Sample coupons were heated isochronally or isothermally, at different temperatures or times, respectively, to probe the recovery kinetics of x-ray peak broadening, x-ray macro-texture, and micro-hardness from the cold rolled state. The inter-alloy region had a strong β-fibre typical of rolled Al. The recovery of the {220} and {311} x-ray line profiles were observed between anneals. The full width half maximum was determined from a pseudo-Voigt fit of the profiles to obtain the defect-related information. Distinct changes in the peak shape and microhardness were observed above 80°C (start of recovery), which goes on all the way to 300°C due to recovery, and beyond 300°C both hardness and peak width drop rapidly (recrystallization start), the latter behaviour being closer to AA3004. Modified Williamson-Hall analysis confirms that recovery is due to dislocation annihilation.

Abstract: A simple model for recovery of a subgrain structure is used to distinguish and explain the respective influence of the deformed microstructure characteristics, annealing temperature and concurrent precipitation kinetics on the nucleation kinetics of recrystallisation. Simulation results demonstrate how the balance between recovery and precipitation kinetics controls nucleation.

Abstract: Twin-roll casting (TRC) is an advantageous substitution for Direct-Chill (DC) casting in the manufacturing of rolled aluminium products. The results of a study of the phase transformations and their interaction with recrystallization occurring during the annealing of TRC Al-Mn based alloys are reported. Four alloys with different contents of Mn, Si and Fe were investigated. Precipitation was studied by resistometric measurements in the course of a heating at linear rate. The microstructural processes responsible for the observed changes in resistivity were identified by TEM examinations of quenched specimens. The changes in the microstructure and solute content during homogenisations at 450°C and 610°C were monitored by conductivity and hardness measurements and polarised light microscopy. It was elucidated that the temperature and kinetics of phase transformations are influenced not only by the content of Mn, but also by Si content. In alloys with low Si content, the decomposition of solid solution and the transformation of primary phases occur in much larger temperature range than in the alloys with high Si content. The precipitation of Mn and Si, concurrent to recrystallization, was observed to retard the latter, especially in alloys with high Mn and Si content.

Abstract: Positron Annihilation Doppler Broadening Spectroscopy (PADPS) is one of the nuclear techniques used in material science. PADPS measurements are used to study the behavior of defect concentration and dislocation density in a set of 3003 and 3005 wrought aluminum alloy. It has been shown that positrons can become trapped at imperfect locations in solids. The S-parameter can be influenced by changes in the concentration of such defects. There is no observed change in the Sparameter values after the saturation of defect concentration. The S-parameter and trapping rates for the samples deformed up to 10 percent were studied. The concentration of defect range varies from 1017 to 1018 cm-3 and from 1016 to 1017 cm-3 for 3003 and 3005 wrought Al alloy respectively. While trapping rate range varies from 1 x1010 to 1.2x1011 s-1 for 3003 and from 1 x109 to 1.2x1010 s-1 for 3005 wrought Al alloy.