Untersuchung von alpha -> gamma Mikrotransformationstexturen in Stahl mittels Orientierungsmikroskopie im hochauflösenden Rasterelektronenmikroskop

Ferrite to austenite transformation in a low carbon micro-alloyed steel was studied by SEM-EBSD (scanning electron microscope based electron back scattered diffraction). The former involved complete or partial transformation of ferrite to austenite to get access to different steps of the transformation. By means of a special preparation technique it was possible to stabilize the high temperature austenitic phase to enable EBSD measurements at room temperature. Local orientation measurements (EBSD) both before and after the transformations helped in establishing the two distinct steps of transformation - nucleation and growth. The material used was a hot strip of low carbon micro-alloyed steel cold rolled to different thickness reductions and finally annealed to obtain recrystallized microstructures with different grain sizes. Nucleation involved formation of austenite mostly at the triple points of the grain boundaries of the ferritic phase without any variant selection between the different possible orientations of nucleating austenite grains. The subsequent growth of austenite grains was often associated with multiple twinning and also possible selective/competitive grain growth. These mechanisms were the origin of the observed transformation texture. A simple transformation texture model based on nucleation at random triple points in ferrite is proposed. The model could offer better predictability, though a noticeable difference between predicted and experimental transformation textures was observed in cases of higher pre-transformation cold reduction. But even in such samples, predictability of the nucleation texture was established.

Grantor dc:publisher

Publikationsserver der RWTH Aachen University

Year dc:date

2004

Author dc:creator

• Park, Chel-Min

Contributors dc:contributor

• Gottstein, Günter

• info:eu-repo/classification/ddc/660
• Niedriglegierter Stahl
• Ferrit-Austenit-Gefüge
• Gefügeumwandlung
• Texturanalyse
• Rasterelektronenmikroskopie
• Technische Chemie
• Transformationstextur
• Phasenumwandlung
• EBSD
• Stahl

Statement dc:rights

• info:eu-repo/semantics/openAccess

Language dc:language

ger

Identifier

https://publications.rwth-aachen.de/search?p=id:%22RWTH-CONV-123650%22

OAI identifier oai:identifier

oai:publications.rwth-aachen.de:62052