Tuning the mechanical properties of materials often depends upon changing the competition/cooperation between fundamental material deformation modes. In this study, novel methods of characterizing atomic strain and classifying atomic environments are described with applications to nanocrystalline materials (NMs). In NMs, variations in material strength with grain size are generally attributed to a transition in the governing deformation mechanisms from dislocation to interface-based. Kinematic strain metrics are leveraged to identify operative deformation modes. Higher-order structural descriptors are utilized to identify and classify grain boundary (GB) structures on the atomic scale, improving the current approaches for GB classification and behavioral prediction. By leveraging this set of descriptors, we then classify GBs into more appropriate behavioral groups based on their atomic composition, further aiding the connection of GB structure to properties. A new understanding emerges regarding the competition of nanoscale mechanisms and is tied to transitions in material strength. This is subsequently utilized to ascertain the fundamentals of alloy strengthening, allowing for precise tuning of mechanical response based on alloy content and grain size.
Dr. Garritt Tucker
Mechanical Engineering Department at Mines in the summer of 2017 as an Assistant Professor and has been active in the interdisciplinary Materials Science program and the Alliance for the Development of Additive Processing Technologies. Before joining Mines, he spent 4 years as an Assistant Professor in the Department of Materials Science and Engineering at Drexel University (Philadelphia, PA), and 2 years as a Postdoctoral Research Appointee at Sandia National Laboratories (Albuquerque, NM) in the Computational Materials and Data Science group. While at Drexel, he was awarded the Outstanding Teacher Award in 2015 and the TMS Young Leader Professional Development Award in 2016. Professor Tucker earned his Ph.D. in 2011 from Georgia Tech, and a B.S. in 2004 from Westminster College majoring in both Physics and Mathematics. At the core of Prof. Tucker’s research group approach is to develop collaborations and programs that effectively mesh computation with experiments to tailor functional materials.