Yanfei Gao's blog
Nanoindentation and Related Materials Phenomena at Small Scales - Symposium for SES 2013 at Brown UniversitySubmitted by Yanfei Gao on Mon, 2012-12-24 03:21.
You may have heard that Brown University will host the SES 50th Annual Technical Meeting and ASME-AMD Annual Summer Meeting (July 28-31, 2013). It is our great pleasure to welcome you to submit abstracts to a symposium -- Nanoindentation and Related Materials Phenomena at Small Scales. Attached is the call for abstract document.
Please visit http://www.brown.edu/Conference/ses2013/ for important dates, abstract submission, and conference registration information.
Yanfei Gao and George M. Pharr
University of Tennessee & Oak Ridge National Laboratory
Postdoctoral Research Associate in Materials Joining Science and Technology at Oak Ridge National LaboratorySubmitted by Yanfei Gao on Fri, 2011-10-14 15:15.
(An opening from a colleague's group at Oak Ridge National Laboratory:)
Postdoctoral research associate positions are available in the area of materials joining and associated science and technology. The research emphases are expected to focus on computational modeling of welding phenomena including heat transfer, stress and distortion, and non-equilibrium phase transformation/microstructure evolution. The successful applicant should have a strong background and interest in materials joining with demonstrated capability of innovative and independent research.
Additional information can be found in the attached, as well as at webpage: https://www3.orau.gov/ORNL_TOppS/Posting/Details/210
Applications and nominations are invited for the position of Professor and Head of the Department of Materials Science and Engineering (MSE) at The University of Tennessee, Knoxville (UTK), College of Engineering (http://www.engr.utk.edu/mse/). A detailed Announcement is enclosed.
We show that it is possible to distinguish between homogeneous and heterogeneous dislocation nucleation on the basis of differences in experimentally measured theoretical strengths. From nanoindentation tests, the critical shear stress for dislocation nucleation in two different Mo-alloy single crystals (Mo-3Nb and Mo-10Al-4Ni) is found to be ~1/8 of the shear modulus. The corresponding stress in uniaxially compressed Mo-10Al-4Ni micropillars is ~1/26 of the shear modulus. This strength difference is due to the higher critical stress required to nucleate a full dislocation loop homogeneously in the bulk as opposed to a half or quarter loop heterogeneously at a surface or edge. PRB 77, 060103(R), 2008.
Symposium on "Mechanics of Nanofabrication and Nanostructure Growth" at the 2007 IMECE (ASME Meeting)Submitted by Yanfei Gao on Thu, 2007-01-25 22:22.
(Please also refer to http://imechanica.org/node/711 for the introduction of this ASME meeting and some important changes. )
Mechanics has been playing a critical role in understanding the fabrication and reliability of nanostructured material systems, such as the self-assembly of quantum dots during heteroepitaxial thin film growth. Sponsored by the Elasticity Committee of Applied Mechanics Division, this symposium will identify opportunities and challenges in mechanics of materials that are motivated from a variety of novel and emerging nanofabrication and nanostructure growth methods. Presentations in experimental, theoretical, and computational studies are solicited in the following areas (but not limited to):
Nanoscale incipient asperity sliding and interface micro-slip assessed by the measurement of tangential contact stiffnessSubmitted by Yanfei Gao on Thu, 2006-11-02 13:13.
Experiments with a multidimensional nano-contact system (Lucas, Hay, and Oliver, J. Mater. Res. 2004) have shown that, prior to kinetic frictional sliding, there is a significant reduction of the tangential contact stiffness relative to the elastic prediction. The reduction occurs at contact sizes below about 50~200nm for aluminum single crystals and several other materials. Using a cohesive interface model, we find that this reduction corresponds to a transition from a small-scale-slip to large-scale-slip condition of the interface.