Universität duisburg-essen-raabe-dd ch-kolloquium

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How to nanostructure 100 thousand tons

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Universität duisburg-essen-raabe-dd ch-kolloquium

  1. 1. Nanostructuring of 100 thousand tonsD. Ponge, J. Millan, L. Yuan, S. Sandlöbes, A. Kostka, P. Choi, T. Hickel, J. Neugebauer, D. Raabe Düsseldorf, Germany WWW.MPIE.DE d.raabe@mpie.de 30. Nov. 2011 Dierk Raabe GDCh Kolloquium Universität Duisburg-Essen
  2. 2. Nanostructures in 100 thousand tons www.mpie.de
  3. 3. The Düsseldorf Local Electrode Atom Probe (LEAP) LaboratoryLEAP 3000X HR, IMAGO Sci. Instr.(since February 2009)• High spatial resolution (Dx ~ 0.2 nm, Dz ~ 0.1 nm)• High mass resolution (Dm/m = 1100, FWHM at 27 Da)• Fast data acquisition rate (max. ~ 2 Mio ions / min)• Large probed volumes (max. ~ 200 x 200 x 1000 nm3)• High detection sensitivity (min. ~ 10 ppm)• Pulsed laser (l = 532 nm, ~ 10 ps) 2/55
  4. 4. New materials for key technologies: Aero-space 3
  5. 5. New materials for key technologies: mobility on land and water 4
  6. 6. New materials for key technologies: Power plants 5
  7. 7. New materials for key technologies: Green energy 6
  8. 8. New materials for key technologies: Health 7
  9. 9. From atomistic understanding towards designing new materials D. Raabe et al. Scripta Materialia 60 (2009) 1141 8
  10. 10. Effect of aging on ductility 1400 aged 450°C/48h 2 Precipitation 1200 hardeningEngineering Stress (MPa) as-quenched 1000 increase of austenite ? 800 2 fraction during aging 1 strain 0% strain 15% 600 400 200 01 0 5 10 15 20 Engineering Strain (%) -Fe (Martensite) -Fe (Austenite), vol. fraction 15-20% D. Raabe et al. Scripta Materialia 60 (2009) 1141 9
  11. 11. Effect of cold rolling after aging 20 12MnPH 18 Why so much austenite 120 K below equilibrium transformation? X-Ray 16Fraction of Austenite (%) ->’ (TRIP) 14  12 formation aged 10 during (450°C/48h) aging 8 450°C/48h 6 4 quenched 2 0 0 5 10 15 20 25 30 Cold Rolling Reduction, % D. Raabe et al. Scripta Materialia 60 (2009) 1141 10
  12. 12. APT results: Atomic map (12MnPH aged 450°C/48h) Martensite decorated by precipitations Austenite ? ?Mn atoms 70 million ionsNi atoms Laser modeMn iso-concentration: 18 at.% (0.4nJ, 54K) 11 Dmitrieva et al. Acta Mater 59 (2011) 11
  13. 13. Aging-induced austenite reversion Mn layer 1 Mn layer 2 Thermo-Calc  equilibrium Mn-conc.: M A 27 at. % Mn in austenite (A) nominal 12 at.% Mn 3 at. % Mn in ferrite (martensite) (M) depletion zone Mn layer 2 Mn layer 1 M A M Mn iso-concentration (18 at.% Mn) Dmitrieva et al. Acta Mater 59 (2011) 12
  14. 14. Aging-induced austenite reversion Mn layer 1 Mn layer 2 Thermo-Calc  Can I push this idea further ? equilibrium Mn-conc.: M A A M 27 at. % Mn in austenite (A) nominal 12 at.% 3 at. % Mn in ferrite (martensite) (M) aging Excellent agreement between phase boundary DICTRA experiment & simulation ! Kinetic freezing and associated austenite reversion ! Dmitrieva et al. Acta Mater 59 (2011) 13
  15. 15. Growth of retained austenite 450°C/48h. 12MnPH 1D. Conc. Profile - Manganese Maraging – TRIP Steel. APT 14
  16. 16. Martensite relaxation & aging & nanoscale austenite reversion650 MPa to 2 GPa Ultra high strength and corrosion resistance 400°C aging: Ms-relaxation + prec. (aging) + austenite reversion Fe-13.6Cr-0.44C (wt.%) 15
  17. 17. Martensite relaxation & aging & nanoscale austenite reversion at 5.45 at.% C, austenite forms at 400°CC has ‘/’ shape in austenite layer: inheritance from austenite, Gibbs adsorption isotherm; C on martensite grain boundariesC has ‘V’ shape in austenite layer: austenite reversion through partitioning and kinetic freezing 16
  18. 18. Self-repair steels 17
  19. 19. Answering societies grand challenges with complex alloys 70% of all industrial innovations are associated with progress in materials science and engineering Specifically, metallic materials occupy key roles (energy, transportation, health, safety, infrastructure) Our mission: Designing new metallic alloys from first principles - Multiscale simulation - Multiscale characterization starting from the atomic scale - Synthesis, processing, testing www.mpie.de

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