Crystallographic Analysis of Isothermally Transformed Bainite in 0.2C-2.0Mn-1.5Si-0.6Cr Steel Using EBSD
来源期刊：JOURNAL OF MATERIALS SCIENCE TECHNOLOG2013年第4期
论文作者：Pasi P.Suikkanen Anthony J.DeArdo L.Pentti Karjalainen
文章页码：359 - 366
摘 要：<正>The crystallography of bainite,transformed isothermally at 450℃in 0.2C-2.0Mn-1.5Si-0.6Cr steel,was investigated by electron backscatter diffraction（EBSD） analysis.The orientation relationship（OR） was found to be closer to Ntshiyama-Wassermann（N-W） than Kurdjumov—Sachs orientation relationship.Bainite microstructure consisted of parallel laths forming a morphological packet structure.Typically,there were three different lath orientations in a morphological packet.These orientations were dictated by a three specific N—W OR variants sharing the same {111} austenite plane.A packet of bainite laths with common {111} austenite plane was termed as crystallographic packet.Generally,the crystallographic packet size corresponded to the morphological packet size.Locally,crystallographic packets with only two dominant orientations were observed.This indicates strong local variant selection during isothermal bainite transformation.The relative orientation between the variants in crystallographic packets was found to be near 60°/<110>.This appears to explain the strong peak observed in the grain boundary misorientation distribution near 60°.Bainite also contained pronounced fraction of boundaries with their misorientation in the range of 2.5°—8°with quite widely dispersed rotation angles.Spatially these boundaries were found to locate inside the bainite laths,forming lath-like sub-grains.
Pasi P.Suikkanen1,2，Anthony J.DeArdo4，L.Pentti Karjalainen5
2. Department of Mechanical Engineering,University of Oulu,P.O.Box 4200,90014 University of Oulu,Finland4. CEA,LITEN,17 rues des Martys,38054 Grenoble,France5. Department of Mechanical Engineering and Materials Science,University of Pittsburgh,848 Benedum Hall,Pittsburgh,PA 15261-2285,USA
摘 要：<正>The crystallography of bainite,transformed isothermally at 450℃in 0.2C-2.0Mn-1.5Si-0.6Cr steel,was investigated by electron backscatter diffraction（EBSD） analysis.The orientation relationship（OR） was found to be closer to Ntshiyama-Wassermann（N-W） than Kurdjumov—Sachs orientation relationship.Bainite microstructure consisted of parallel laths forming a morphological packet structure.Typically,there were three different lath orientations in a morphological packet.These orientations were dictated by a three specific N—W OR variants sharing the same {111} austenite plane.A packet of bainite laths with common {111} austenite plane was termed as crystallographic packet.Generally,the crystallographic packet size corresponded to the morphological packet size.Locally,crystallographic packets with only two dominant orientations were observed.This indicates strong local variant selection during isothermal bainite transformation.The relative orientation between the variants in crystallographic packets was found to be near 60°/<110>.This appears to explain the strong peak observed in the grain boundary misorientation distribution near 60°.Bainite also contained pronounced fraction of boundaries with their misorientation in the range of 2.5°—8°with quite widely dispersed rotation angles.Spatially these boundaries were found to locate inside the bainite laths,forming lath-like sub-grains.
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