Seminar by Jian WANG (University of Nebraska-Lincoln) “PURE-SHUFFLE MECHANISMS IN SOLID-SOLID PHASE TRANSFORMATION”


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Date | Time
06/06/2016 | 2 h 00 min

Location
Salle Klepaczko

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Seminar by Jian WANG (University of Nebraska-Lincoln)

“PURE-SHUFFLE MECHANISMS IN SOLID-SOLID PHASE TRANSFORMATION”

Mechanical and Materials Engineering, University of Nebraska-Lincoln, Lincoln, NE 68588-0526; Los Alamos National Laboratory, Los Alamos, NM 87544 USA

Keywords: Pure-shuffle, Phase transformation, Deformation twin, Atomic scale

Abstract:

Solid-solid phase transformation, such as the transformation between different crystal structures (i.e., face centered cubic vs. body centered cubic, hexagonal close-packed vs. face centered cubic, etc.) and the reorientation of one crystal structure (i.e. twinning), often occurs associated with either temperature change or mechanical loading. Under mechanical loading, the formation of new phase can accommodate plastic deformation which is referred to as phase transformation induced strain or twin induced strain with respect to the transformation type. The created boundaries consequently act as barriers for dislocation motion, in turn, strengthening materials. Using high-resolution transmission electron microscopy (HRTEM) and atomistic simulations (density function theory and molecular dynamics), we explored pure-shuffle transformation mechanisms for nucleation of (i) a face-centered cubic titanium in hexagonal close packed titanium, (ii) zinc-blende InAs in wurtzite InAs nanowires, and (iii) deformation twin {10-12} in hexagonal metals and growth or annealing twins in face-centered cubic metals. The growth of these structures can be accomplished through either shear shuffle or pure shuffle mechanisms, depending on whether marco-scale shear strains will be resulted.

Bio:

Dr. Jian Wang is an Associate Professor at Mechanical and Materials Engineering at University of Nebraska-Lincoln. He received his Ph.D in Mechanical Engineering, Rensselaer Polytechnic Institute, Troy, NY, USA, in 2006. After that, He joined Los Alamos National Laboratory and has been working as Technical Staff Member for 9 years. Currently, his research interests are focused on more quantitative exploring the structure-properties relationships of structural and nanostructured materials. He was awarded International Journal of Plasticity Young Research Award, 2015; TMS MPMD Young Leader Professional Development Award, 2013; the LDRD/Early Career Award (2011); and the LANL Distinguished Postdoctoral Performance Award in 2009. He was leading two DoE BES Core programs with focus on (1) Deformation Physics of Ultra-fine Materials and (2) Multiscale Constitute Laws for HCP materials; and two LDRD-ER Award (2013), Los Alamos National Laboratory, USA. He has ~2000 peer-reviewed publications (>4600 citations and H-index = 42, 25 papers selected as 25 Hottest Articles in Materials Science), two book chapters in Dislocations in Solids and 55+ invited/keynote presentations. He is serving as Editorial Boards for several materials journals.