Please consider attending the following: MATERIALS ENGINEERING SEMINAR "Deformation Twinning in Nanocrystalline Al" By Yifan Zhang Purdue MSE Ph.D. Preliminary Exam Advisor: Professor Xinghang Zhang ABSTRACT Deformation twinning is one of the major deformation mechanisms in metallic materials to accommodate shear strain and plastic deformation. As widely accepted, Al rarely deforms via deformation twinning because of its high stacking fault energy (142-165 mJ/m2). Only under certain conditions, such as cryogenic temperature, extremely high strain rate, addition of solutes as well as nanoscale grain size, can deformation twins form in Al. Experimental studies and molecular dynamic simulations have revealed the important roles of grain boundaries on the deformation twinning in nanocrystalline (NC)Al. Several GB-mediated twinning mechanisms will be discussed in this work. Date: Monday, November 6, 2017 Time: 11:30 A.M. Place: ARMS B071