Brown University School of Engineering

Joint Materials/Solid Mechanics Seminar Series “In Situ Materials Science: Probing Microstructural Evolution of Deforming Materials in Real-Time”

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Monday, December 03, 2012 4:00pm - 5:00pm

Joint Materials/Solid Mechanics Seminar Series “In Situ Materials Science: Probing Microstructural Evolution of Deforming Materials in Real-Time” N. Chawla Fulton Professor of Materials Science and Engineering Arizona State University Tempe, AZ 85287-6106 Abstract: The field of materials science and engineering (MSE) is based on the fundamental principle that microstructure controls properties. Traditionally, the study of material structure has been limited by sectioning and post mortem observations. This approach is often inaccurate or inadequate for solving many cutting-edge problems. It is also often laborious and time-consuming. Advances in experimental methods, analytical techniques, and computational approaches, have now enabled the development of in situ techniques that allow us to probe the behavior of materials in real-time. The study of microstructures under an external stimulus (e.g., stress, temperature, environment) as a function of time is particularly exciting. Examples include an understanding of time-dependent deformation structures, phase transformations, compositional evolution, magnetic domains, etc. X-ray synchrotron tomography, for example, provides a wonderful means of characterization damage in materials non-destructively. In this talk, I will describe experiments and simulations that address the critical link between microstructure and deformation behavior, by using a three-dimensional (3D) virtual microstructure obtained by x-ray synchrotron tomography. The approach involves capturing the microstructure by novel and sophisticated in situ tensile testing in an x-ray synchrotron, followed by x-ray tomography and image analysis, and 3D reconstruction of the microstructure. Case studies on fundamental deformation phenomena in aluminum and tin-based materials will be presented and discussed. In addition, in situ deformation behavior can be conducted inside a scanning electron microscope (SEM). We have conducted indentation experiments in Sn-based films to investigate the fundamentals of Sn whiskering in these materials. The influence of indentation environment, as well as the compressive stresses in the film will be discussed. Monday, December 3, 2012 4:00-5:00 p.m. B&H Room 190