DATE: Wednesday, October 10, 2018
TIME: 12:00 – 1:00pm
Topic: Quantitative In-Situ Study of Low Dimensional Materials and Related Interfaces
Dept. of Materials Science & NanoEngineering
Rice University, Houston, Texas
This talk presents some of our past efforts to quantitatively study the nanomechanical behaviors of low dimensional materials and related systems inside electron microscopes. In the first example, we will show that, under uni-axial tensile loading, single crystalline ultrathin gold nanowires might fracture in two modes, displaying distinctively different fracture morphologies and ductility. In situ HRTEM study suggests that the unexpected brittle-like fracture was closely related to the observed twin structures, which is very different from surface dislocation nucleation/propagation mediated mechanism in ductile fracture mode. In the second example, we will discuss our recent studies to probe the important interfaces in several graphene and CNT based hybrid systems including nanocomposites and three-dimensional carbon nanostructures. The implications of such studies on designing nanocomposites and hybrid systems with better performances will also be discussed. In the third and final example, we will report our recent efforts to determine the engineering relevant fracture toughness of graphene with pre-existing defects, rather than the intrinsic strength that governs the uniform breaking of atomic bonds in perfect graphene. Strategies on how to improve the fracture resistance in graphene are explored.
Jun Lou obtained B.E. and M.S. degrees in Materials Science and Engineering from Tsinghua University and Ohio State University, respectively, and his Ph.D. degree from the Department of Mechanical and Aerospace Engineering and Princeton Materials Institute at Princeton University. After a brief postdoc at Brown University he joined Rice University, and directs the Nanomaterials, Nanomechanics and Nanodevices Lab (N3L). He is currently a full professor and the associate chair of the department of Materials Science and NanoEngineering. Lou is an AFOSR Young Investigator and a recipient of Charles Duncan Award for Outstanding Academic Achievement at Rice. He is currently the Editor-in-Chief of Materials Today, the Elsevier flagship journal (Impact factor: 24.537) covering original research and reviews in the broader materials science community. Lou has extensive experience in the synthesis and design of 2D materials beyond Graphene; mechanical and multi-physics characterization, and fabrication of advanced material systems and devices. He currently serves as the site director for the NSF industry university collaborative research center (IUCRC) of Atomically Thin Multifunctional Coatings (ATOMIC) that has 13 member companies, exploring potential applications of 2D materials in different industries with commercial partners.