An emerging insight in materials science is that interfaces, including grain boundaries and interphase boundaries, may be treated as distinct thermodynamic phases called complexions. This has been a useful new concept to explain abnormal grain growth in ceramic systems such as Al2O3. The purpose of this study is to explore the possible existence of complexions in the Fe-Si system which exhibits some strong similarities in the grain growth behavior to that shown by Al2O3. High resolution electron microscopy (HRTEM) and Scanning Transmission Electron Microscopy (STEM) with Energy dispersive X-ray (EDX) analysis was carried out to understand the nature of grain boundaries and the existence of any possible complexions by comparing both abnormal and normal grain boundaries types. We will also report kinetic studies on the nucleation density of abnormal grains in Fe-Si as a function of temperature since this has been found to be a strong indicator of the occurrence of complexions in ceramic systems. This work was done in collaboration with Carnegie Mellon University, Pittsburg, Pa. USA.
Subba Rao Karavadi studied undergraduate degree in Physics major and Chemistry minor from Nagarjuna University, India and Masters Degree in Physics from Andhra University, India. He received his PHD in Physics from Max-Plank-Institute for Chemical Physics of Solids, Dresden / Technical University of Dresden in 2006. He spent 2 years as a postdoctoral research associate before coming to Rutgers in 2008.