On Achieving a Better Understanding of the Polygonal Ferrite Microstructure in IF Steel Using Image Quality Analysis

Abstract

The image quality of the diffraction pattern from EBSD has been used as an index distinguishing the degree of lattice imperfection. Since austenite decomposition products formed at different transformation temperatures have various dislocation or sub-grain boundary densities, this technique has been used to identify, group, and quantify the different types of ferrite. This article presents a study where the dislocation density variation, associated with different cooling rates from the austenite in a commercial IF steel, will be analyzed using this image quality analysis. Perhaps the most significant contribution of this work is the new insight into the strengthening mechanisms found in these steels.

Keywords:

• Dislocation density
• EBSD
• Ferrite
• IF Steel
• Image quality
• Microstructure
• Steel

ACKNOWLEDGMENTS

This work was supported by the Basic Metals Processing Research Institute (BAMPRI) of the Department of Materials Science and Engineering, University of Pittsburgh and their industrial sponsors as the Ph.D. research project of the first author. This generous support is greatly appreciated.