The Indian Institute of Technology Bombay organised an Institute Lecture by Prof. Peter Voorhees, Frank C Engelhart, Professor of Materials Science and Engineering Northwestern University, Evanston, IL, USA on Solidification in 4D: from Dendrites to Eutectics.
Understanding the role of materials processing is central to the materials science engineering paradigm of linking the composition of a material with its properties. Unfortunately, establishing this link has been hampered by the inability to follow the evolution of the microstructure of a material in three dimensions and as a function of time (4D). With the advent of high-energy X-ray sources, it is now possible to follow solidification processes in three dimensions and as a function of time. The ability to observe and quantify the solidification process in metals on sub-second time scales and micron spatial scales in three dimensions provide fundamentally new insights into this complex phase transformation. For example, using this approach, we are able to follow and quantify the evolution of dendrites in four dimensions. These complex tree-like structures are inherent to the solidification of metal alloys from steel to aluminum. The factors controlling their morphology and evolution, along with other solidification structures, were discussed.
About the Speaker:
Prof. Peter Voorhees is the Frank C. Engelhart Professor of Materials Science and Engineering and (by courtesy) Professor of Engineering Sciences and Applied Mathematics. He is elected to the American Academy of Arts and Sciences in 2016. His other recognitions include Fellow, The Minerals, Metals and Materials Society (2013), J. Willard Gibbs Phase Equilibria Award, ASM International (2013), Fellow, American Physical Society, Material Physics Division (2005), Highly Cited Researcher, Institute for Scientific Information (2002), Fellow, ASM International (2001), and, Materials Science and Engineering Teacher of the Year (1999). His research group is focused on the kinetics of phase transformations using experiment, simulation, and theory. These phase transformations range from the growth of nanowires from the vapor and graphene, to the solidification of alloys. They measure the evolution of interfacial morphology during phase transformations using techniques such as time resolved three-dimensional X-ray tomography and automated serial sectioning. Their recent studies on simulations of phase transformations include work on a method to follow the atomic structure of a material on diffusional time scales and the growth of oxides on metal surfaces. His research work also combines the experiments with simulations by using the measured three-dimensional interfacial morphologies as initial conditions in simulations and then comparing the results of the simulations and experiment at some later time. Through their involvement in Northwestern’s Center for Hierarchical Materials Design, they use these models to design materials with novel properties, such as Si-based in situ composite materials