Mesoscale Anisotropic Deformation and Damage Nucleation In Polycrystalline Ti Alloy

Friday, February 24, 2012 3:00 pm – 4:00 pm
Room 610, M&M Building

M. A. Crimp
Chemical Engineering and Materials Science
Michigan State University, East Lansing, MI

Abstract

A combination of experimental characterization and crystal plasticity finite element modeling(CPFEM) has been used to study the anisotropic deformation of a number of titanium alloys.Studies have been carried out in the near surface region of 4-point bend specimens, where theglobal stress can be approximated as uniaxial tension.  Specific microstructural patches havebeen characterized prior to deformation using electron backscattered electron diffractionorientation imaging microscopy (OIM).  Specimens have been deformed both in-situ in scanningelectron microscopy (SEM) and ex-situ, facilitating a range of experimental characterizationmethods including optical microscopy, atomic force microscopy, SEM based backscatteredelectron imaging, OIM, and channeling contrast imaging, as well as 3-D X-ray diffraction.  Thesestudies have allowed a comprehensive experimental characterization of the nature of plasticdeformation and damage nucleation in the microstructural patches.  To complement thesestudies, quasi 3-D FEM meshes, developed based the experimentally characterizedmicrostructural patches, have been computationally deformed.  While the simulations accuratelyreproduce significant aspects of the experimental studies, including some crystal rotations andsurface topography development, further work to include grain boundary behavior in thesimulations is needed.

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