High manganese conference Korea ECCI

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Imaging of dislocations and twins in TWIP steels using electron channeling contrast imaging under controlled diffraction conditions in a scanning electron microscope

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High manganese conference Korea ECCI

  1. 1. Imaging of dislocations and twins in TWIP steels using electron channeling contrast imaging under controlled diffractionconditions in a scanningelectronmicroscope<br />IvanGutierrez-Urrutia, Stefan Zaefferer, Dierk Raabe<br />Düsseldorf, Germany<br />WWW.MPIE.DE<br />d.raabe@mpie.de<br />Dierk Raabe<br />
  2. 2. Overview<br /><ul><li>Motivation
  3. 3. Electronchannelingcontrastimaging
  4. 4. Dislocationandtwinstructures in Fe-22 wt.%Mn-0.6 wt.% C duringtensiletesting
  5. 5. Conclusions</li></ul>Dierk Raabe (d.raabe@mpie.de)<br />1<br />www.mpie.de<br />
  6. 6. 2<br />EBSD: Workhardeningof TWIP steels, Fe-22Mn-0.6C (wt%)<br />Kippwinkel<br />I. Gutierrez-Urrutia, S. Zaefferer, D. Raabe; ScriptaMaterialia 61 (2009),pp. 737-740<br />I. Gutierrez-Urrutia, S. Zaefferer, D. Raabe; Materials Science and Engineering A 527 (2010), pp. 3552-3560<br />www.mpie.de<br />
  7. 7. Overview<br /><ul><li>Motivation
  8. 8. Electronchannelingcontrastimaging
  9. 9. Dislocationandtwinstructures in Fe-22 wt.%Mn-0.6 wt.% C duringtensiletesting
  10. 10. Conclusions</li></ul>Dierk Raabe (d.raabe@mpie.de)<br />3<br />www.mpie.de<br />
  11. 11. EBSD: Workhardeningof TWIP steels, Fe-22Mn-0.6C (wt%)<br />twins<br />40%<br />TA<br />TA<br />step size: 50 nm<br />10%<br />tensile test, room temperature<br />20%<br />YS: yieldstrength; UTS: ultimatetensilestrength<br />4<br />I. Gutierrez-Urrutia et al. Scripta Mater. 61 (2009) 737-740<br />
  12. 12. ECCI: Workhardeningof TWIP steels, Fe-22Mn-0.6C (wt%)<br />hardening stage: <br />2%<e< 10%<br />-Planar slip structures + wavy structures<br />-Few mechanical twins<br />YS: yieldstrength; UTS: ultimatetensilestrength<br />5<br />I. Gutierrez-Urrutia et al. Scripta Mater. 61 (2009) 737-740<br />
  13. 13. ECCI: Workhardeningof TWIP steels, Fe-22Mn-0.6C (wt%)<br />hardening stage: <br />2%<e< 10%<br />6<br />I. Gutierrez-Urrutia et al. Scripta Mater. 61 (2009) 737-740<br />
  14. 14. ECCI: Workhardeningof TWIP steels, Fe-22Mn-0.6C (wt%)<br />hardening stage: <br />10%<e< 25%<br />-Wavy structures: dislocation cells<br />-Mechanical twins<br />-3 types of grains<br />YS: yieldstrength; UTS: ultimatetensilestrength<br />7<br />I. Gutierrez-Urrutia, et al. Mater. Sc. Engin. A 527 (2010) 3552<br />
  15. 15. ECCI: Workhardeningof TWIP steels, Fe-22Mn-0.6C (wt%)<br />hardening stage: <br />10%<e< 25%<br />8<br />I. Gutierrez-Urrutia, et al. Mater. Sc. Engin. A 527 (2010) 3552<br />
  16. 16. ECCI: Workhardeningof TWIP steels, Fe-22Mn-0.6C (wt%)<br />hardening stage: <br />10%<e< 25%<br />Type I<br />9<br />I. Gutierrez-Urrutia, et al. Mater. Sc. Engin. A 527 (2010) 3552<br />
  17. 17. ECCI: Workhardeningof TWIP steels, Fe-22Mn-0.6C (wt%)<br />hardening stage: <br />10%<e< 25%<br />Type II<br />10<br />I. Gutierrez-Urrutia, et al. Mater. Sc. Engin. A 527 (2010) 3552<br />
  18. 18. ECCI: Workhardeningof TWIP steels, Fe-22Mn-0.6C (wt%)<br />hardening stage: <br />10%<e< 25%<br />Message:<br />Not only isotropic: <br />BUT: <br />implement in tensorial solver<br />Type III<br />11<br />I. Gutierrez-Urrutia, et al. Mater. Sc. Engin. A 527 (2010) 3552<br />
  19. 19. ECCI: Workhardeningof TWIP steels, Fe-22Mn-0.6C (wt%)<br />5th hardeningstage: <br /> 35%<e< 50%<br />12<br />I. Gutierrez-Urrutia, et al. Mater. Sc. Engin. A 527 (2010) 3552<br />
  20. 20. Overview<br /><ul><li>Motivation
  21. 21. Electronchannelingcontrastimaging
  22. 22. Dislocationandtwinstructures in Fe-22 wt.%Mn-0.6 wt.% C duringtensiletesting
  23. 23. Conclusions</li></ul>Dierk Raabe (d.raabe@mpie.de)<br />13<br />www.mpie.de<br />
  24. 24. Overview<br /><ul><li>ECCI: excellentformappingdislocations, twins, andinteractionsatwidefieldofview
  25. 25. Meanfreedislocationpathandstrainhardeningdeterminedbydeformationtwinspacing
  26. 26. <111>//deformation axis: multiple twins, planar dislocation fields, cells
  27. 27. <112>//deformation axis: single twin dominance, planar dislocation fields, cells
  28. 28. <001>//deformation axis: wavy dislocation substructures, no twins
  29. 29. 0.1 true strain: less than 20% of all grains contain deformation twins
  30. 30. 0.3 true strain: 90% of all grains contain deformation twins
  31. 31. Orientation dependence: type I grains: low deformation twinning activity; type II grains: well-developed twin substructure along one active twinning system (primary twin system); type III grains: well-developed twin substructure along more than one active twinning system (primary and secondary twin systems).</li></ul>14<br />www.mpie.de<br />

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