Applied Microscopy

Korean Society of Microscopy (한국현미경학회)
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A Correlative Approach for Identifying Complex Phases by Electron Backscatter Diffraction and Transmission Electron Microscopy

  • Na, Seon-Hyeong (Department of Materials Science and Engineering, Pohang University of Science and Technology) ;
  • Seol, Jae-Bok (National Institute for Nanomaterials Technology, Pohang University of Science and Technology) ;
  • Jafari, Majid (Department of Materials Science and Engineering, Pohang University of Science and Technology) ;
  • Park, Chan-Gyung (Department of Materials Science and Engineering, Pohang University of Science and Technology)
  • Received : 2017.01.09
  • Accepted : 2017.02.18
  • Published : 2017.03.30
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Abstract

A new method was introduced to distinguish the ferrite, bainite and martensite in transformation induced plasticity (TRIP) steel by using electron backscatter diffraction (EBSD) and transmission electron microscopy (TEM). EBSD is a very powerful microstructure analysis technique at the length scales ranging from tens of nanometers to millimeters. However, iron BCC phases such as ferrite, bainite and martensite cannot be easily distinguished by EBSD due to their similar surface morphology and crystallographic structure. Among the various EBSD-based methodology, image quality (IQ) values, which present the perfection of a crystal lattice, was used to distinguish the iron BCC phases. IQ values are very useful tools to discern the iron BCC phases because of their different density of crystal defect and lattice distortion. However, there are still remaining problems that make the separation of bainite and martensite difficult. For instance, these phases have very similar IQ values in many cases, especially in deformed region; therefore, even though the IQ value was used, it has been difficult to distinguish the bainite and martensite. For more precise separation of bainite and martensite, IQ threshold values were determined by a correlative TEM analysis. By determining the threshold values, iron BCC phases were successfully separated.

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References

  1. Calcagnotto M, Ponge D, and Raabe D (2008) Ultrafine grained ferrite/martensite dual phase steel fabricated by large strain warm deformation and subsequent intercritical annealing. ISIJ Int. 48, 1096-1101. https://doi.org/10.2355/isijinternational.48.1096
  2. De Cooman B C (2004) Structure-properties relationship in TRIP steels containing carbide-free bainite. Curr. Opin. Solid State Mater. Sci. 8, 285-303. https://doi.org/10.1016/j.cossms.2004.10.002
  3. Fischer F D, Reisner G, Werner E, Tanaka K, Cailletaud G, and Antretter T (2000) A new view on transformation induced plasticity (TRIP). Int. J. Plast. 16, 723-748. https://doi.org/10.1016/S0749-6419(99)00078-9
  4. Giannuzzia L A and Stevieb F A (1999) A review of focused ion beam milling techniques for TEM specimen preparation. Micron 30, 197-204. https://doi.org/10.1016/S0968-4328(99)00005-0
  5. Herrera C, Ponge D, and Raabe D (2011) Design of a novel Mn-based 1 GPa duplex stainless TRIP steel with 60% ductility by a reduction of austenite stability. Acta Mater. 59, 4653-4664. https://doi.org/10.1016/j.actamat.2011.04.011
  6. Humphreys F J (2001) Grain and subgrain characterisation by electron backscatter diffraction. J. Mater. Sci. 36, 3833-3854. https://doi.org/10.1023/A:1017973432592
  7. Matsumura O, Sakuma Y, and Takechi H (1987a) Enhancement of elongation by retained austenite in intercritical annealed 0.4C-1.5Si-0.8Mn Steel. ISIJ Int. 27, 570-579. https://doi.org/10.2355/isijinternational1966.27.570
  8. Matsumura O, Sakuma Y, and Takechi H (1987b) TRIP and its kinetics aspects in austempered 0.4C-1.5Si-0.8Mn steel. Script Metall. 21, 1301-1306. https://doi.org/10.1016/0036-9748(87)90103-7
  9. Matsumura O, Sakuma Y, and Takechi H (1991) Mechanical properties and retained Austenite in intercritically heat treated bainite-transformed steel and their variations with Si and Mn additions. Metall. Trans. A 22A, 489-498.
  10. Mujica L, Weber S, Pinto H, Thomye C, and Vollertsene F (2010) Microstructure and mechanical properties of laser-welded joints of TWIP and TRIP steels. Mater. Sci. Eng. A 527, 2071-2078. https://doi.org/10.1016/j.msea.2009.11.050
  11. Petrov R, Kestens L, Wasilkowska A, and Houbaert Y (2007) Microstructure and texture of a lightly deformed TRIP-assisted steel characterized by means of the EBSD technique. Mater. Sci. Eng. A 447, 285-297. https://doi.org/10.1016/j.msea.2006.10.023
  12. Pinard P T, Schwedt A, Ramazani A, Prahl U, and Richter S (2013) Characterization of dual-phase steel microstructure by combined submicrometer EBSD and EPMA carbon measurements. Microsc. Microanal. 19, 996-1006.
  13. Wilson A W and Spanos G (2001) Application of orientation imaging microscopy to study phase transformations in steels. Mater. Charact. 46, 407-418. https://doi.org/10.1016/S1044-5803(01)00140-1
  14. Wu J, Wray P, Garcia C, Hua M, and Deardo A (2005) Image quality analysis: a new method of characterizing microstructures. ISIJ Inter. 45, 254-262. https://doi.org/10.2355/isijinternational.45.254
  15. Zaefferer S, Ohlert J, and Bleck W (2004) A study of microstructure, transformation mechanisms and correlation between microstructure and mechanical properties of a low alloyed TRIP steel. Acta Mater. 52, 2765-2778. https://doi.org/10.1016/j.actamat.2004.02.044