Microstructures Characterization of Quenched Rebars Using Electron Back-Scatter Diffraction Technique

Concrete reinforcing bars (rebars) produced through water quenching process exhibit composite microstructure due to different cooling rates experienced within the material cross section during processing. These bars are characterized by their higher strength and comparitively better corrosion resistance in concrete as compared to those produced through conventional hot rolling process. These characteristics are attributed to the composite microstructre of these rebars. The development of Electron Back-Scatter Diffraction (EBSD) method offers an innovative way to analyze such microstructures more effectively and efficiently than the traditional light microscopy or Scanning Electron Microscopy (SEM). The extensive measurement tools available with EBSD, such as image quality values and precise grain boundary misorientation angles, provide new approaches to characterize microstructures. The fact that the different ferrite morphologies, studied in this work, exist within the same sample though at different locations, reduces the effect of experimental set-up and specimen preparation on pattern quality. A thorough understanding of these complex microstructures is important to control the resultant mechanical properties and evaluate the corrosion behavior for such steel rebars.