model will be described with emphasis on the successes of the model but the challenges for future work will also be addressed. 3:00 PM Break 3:30 PM Through Process Simulation of Al-Sheet Production – a TextureBased and a Texture-Free Approach: Thiemo Brüggemann1; 1Institute of Physical Metallurgy and Metal Physics, RWTH-Aachen University The simulation of whole processing chains of Al-sheet production is an attractive research topic for the aluminum industry, since a numerical mapping of the process has the potential to predict final properties and influences of single parameters in a cost-efficient way. In this work a modular through-process modeling set-up is presented, allowing for different combinations of time- and partially space-resolved simulation tools. In a first combination, a dislocation density based model, being capable of simulating work-hardening, recovery and recrystallization, is coupled with a roll-gap model. Thus, recrystallization-kinetics and stresses of whole processing-chains can be calculated within minutes. The second combination includes texture simulation. Rolling textures are simulated by a grain-interaction model. During recrystallization texture evolution and kinetics are calculated by a cellular automaton. Both sequences account for micro-chemistry effects and use industrial rolling-schedules as input. Simulation results will be compared to findings from industrially processed Al-sheet and experimental results.
Phase Transformations 5
Program Organizers: William Cassada, Alcoa Technical Center; Hasso Weiland, Alcoa Technical Center; Anthony Rollett, Carnegie Mellon University Symposium Organizers: Gary Shiflet, University of Virginia; Dave Laughlin, Carnegie Mellon University Wednesday PM June 6, 2012
Room: Connan Location: University Student Center
Session Chair: Alexis Deschamps, Grenoble Institute of Technology 2:00 PM A Study of Stress Effects on Beta-Phase Precipitation in Al-Mg Alloys Using In-Situ TEM: Daniel Scotto D’Antuono1; Jennifer Gaies2; William Golumbfskie2; Mitra Taheri3; 1Drexel University ; 2Naval Surface Warfare Center; 3Drexel University The 5xxx series aluminum-magnesium alloys are non-heat treatable metals commonly found in structural applications due to excellent corrosion resistance and weldability. Despite these strong characteristics these systems are prone to sensitization which leads to failure. Here, magnesium segregates toward grain boundaries and precipitates as Al3Mg2 (ß-phase). This ß-phase renders the alloy susceptible to intergranular and stress corrosion cracking (IGSCC). Aging exposure to medium/high temperatures, corrosive environments, and load contribute to the overall failure. Current studies on 5xxx sensitization have neglected to examine the effects of stress along with temperature on ß-phase formation. In this work, the ß-phase precipitation mechanism is observed by conducting simultaneous heating and straining experiments using in-situ TEM. This will allow for the determination of the time, temperature, and stress that give rise to the sensitization. Understanding the precipitation of ß-phase is necessary to mitigate and prevent its formation and thus reduce the susceptibility of these alloys.
13th International Conference on Aluminum Alloys
Technical Program
4:10 PM TCAL1 and MOBAL2 - The Development and Validation of New Thermodynamic and Mobility Databases for Aluminium Alloys: Paul Mason1; Andreas Markstrom2; Y Du3; S. Liu3; J. Zhang3; L Kjellqvist2; J Bratberg2; A Engstrom2; Q. Chen2; 1Thermo-Calc Software Inc.; 2ThermoCalc Software AB; 3Central South University CALPHAD based software tools together with related thermodynamic and kinetic databases have been applied extensively to the modeling of Al alloys for decades. The approach relies on the capability to provide fundamental phase equilibrium and phase transformation information in materials of industrial relevance, which is possible due to the adopted methodology where free energy or atomic mobility of each phase in a multicomponent system is modeled hierarchically from lower-order systems, and model parameters are evaluated by considering both ab-initio and various experimental data. A new thermodynamic database, and a corresponding mobility database is presented for Al-base alloys based on the critical evaluation of all the constituent binary systems across their
4:30 PM Aluminum is Aluminum, Right?: Chandler Becker1; Ellad Tadmor2; 1 NIST; 2Dept. of Aerospace Engineering and Mechanics, University of Minnesota Atomistic simulations are becoming more widely used in a variety of areas, including industrial research and development. However, substantial barriers limit the broad use of these methods, both on their own and as part of an Integrated Computational Materials Engineering (ICME) or multiscale/hierarchical approach. These barriers include the availability of interatomic potentials to model atomic interactions for particular systems, methods to compare them, and tools to assess their accuracy (including uncertainties). We will address the development of the Knowledgebase of Interatomic Models (openKIM.org) as a resource for interatomic potentials and associated tests of their properties. To highlight how calculated properties can depend on the interatomic potential, we will present work with aluminum to compare molecular simulation results with experiment and/or first-principles calculations. We will also discuss major issues identified in the annual NIST “Atomistic Simulations for Industrial Needs” workshops that are designed to facilitate interactions between industrial and academic researchers.
WEDNESDAY PM
3:50 PM Modeling the Recrystallization Textures in Al Alloys after Various Rolling Reductions: Jurij Sidor1; Roumen Petrov1; Leo Kestens1; 1 University Gent Different degrees of rolling reductions account for diverse recrystallization mechanisms and thus different microstructural and texture features. The microstructure and texture of deformed and recrystallized materials is strongly affected by the material’s chemistry and the rolling conditions. The chemical composition of the material controls the formation of large non-deformable particles while the strain magnitude and the friction conditions affect the deformation flow around the hard inclusions and deformation flow across the thickness, respectively. The presence of large constituent particles produces strain heterogeneities during cold rolling which causes specific texture development. The development of deformation and recrystallization textures is discussed based on experimental data and results of finite element and crystal plasticity simulations. A recrystallization model is presented that incorporates the microstructural heterogeneities and changes in local stored energy. The experimental observations and results of crystal plasticity calculations testify that orientation selection during recrystallization is controlled by low stored energy nucleation.
full range of composition and 59 ternaries, 15 quaternaries and 1 quinary. This database contains all the important Al-based alloy phases within a 26-element framework [Al-Cu-Fe-Mg-Mn-Ni-Si-Zn-B-C-Cr-Ge-SnSr-Ti-V-Zr-Ag-Ca-H-Hf-K-La-Li-Na-Sc] and in total 345 solution and intermetallic phases are included.
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