integrated computational materials engineering tools for ...of dislocations with the primary...
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Lawrence Livermore
National Laboratory
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Integrated Computational Materials Engineering Tools for Optimizing Strength of Forged Al-Li Turbine Blades
for Aircraft Engines
NeedInvestigate aluminum
• Current aircraft engine’s fan blades are made of titanium
• Develop blades from lighter materials, such as aluminum alloys
• Build a crystal plasticity model to predict strength of aluminum/lithium alloys
• Strength model should make a clear physical connection between strengthening and microstructural features
• LLNL’s team has experience building strength models for BCC materials
Sylvie Aubry (LLNL), Tom Arsenlis (LLNL), John Allison (UMich), and Alex Staroselsky (UTRC)
Also in collaboration with Brett Wayne (LLNL), Kai Sun (UMich), Luke Borowski (UTRC) and Jacob Garves (UMich)
BenefitsLightweight alloys will save energy in the transportation sector
• Aircraft weight is an important factor in fuel economy.
• Develop blades from lighter materials, such as aluminum alloys reduces that weight
• Anticipated weight saving from substituting Ti blades to Al-Li ones is 20% - 25%. Total weight saving per engine is about 75 lbs. Total amount of fuel saving 13.5 million gallons per year.
• Expected savings are $26M per year.
Approach Predict strength of AL-Li materials through simulations of dislocations defects interactions and evolution
Use dislocation dynamics simulations of the interaction of dislocations with the primary precipitates to provide strength of proposed Al-Li alloys.
Investigate the influence of precipitate density and morphology on the strength of the alloy provided by the LIFT
Simulation of precipitate hardening in alloys includes full elastic interactions between dislocations, the evolution of dislocation networks, and the treatment of the precipitates as finite nanoscale objects locally interacting with the dislocations.
Execute large-scale dislocation dynamics simulations on supercomputing facilities at LLNL to sweep the potential parameter space of the precipitate microstructure, to provide sufficient statistical information to the LIFT team.
ResultsResults show up to 8x higher strength of Al-Li alloys compared to pure Al• Development of new dislocation mobility law
for Aluminum materials• Development of new dislocation mobility law
for Al/Li alloys• Execute pure aluminum large-scale
simulations• Creation of ellipsoidal precipitates of
different kinds• Periodic arrays of precipitates • Large-scale simulations of aluminum with
lithium precipitates
This research was supported by the High-Performance Computing for Manufacturing Project Program (HPC4Mfg), managed by the U.S. Department of Energy Advanced Manufacturing Office within the Energy Efficiency and Renewable Energy Office. It was performed under the auspices of the US Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. Release number: LLNL-POST-725841
Comparison of the stress/strain response between pure aluminum and aluminum with 1% to 5% lithium.
Precipitate strengthening
0
50
100
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450
0 0.0005 0.001 0.0015 0.002 0.0025 0.003 0.0035 0.004
Stre
ss (M
Pa)
Plastic Strain
Aluminum with 1% LithiumAluminum with 2% LithiumAluminum with 3% LithiumAluminum with 4% LithiumAluminum with 5% Lithium
Different types of precipitates: spherical, T, and θ’
Dislocation dynamics using the ParaDiS capability
TEM visualization of precipitates in Al/Li alloys
Fan blade in aircraft engine
Provide yield strength data as a function of particle size, shape and density that can be used to determine the functional forms for crystal plasticity models developed at UM and UTRC as part of the ICME effort tooptimize the processing of these alloys for aircraft engine environments.
lithium alloys to replace heavier titanium components in aircraft engine parts