Multi-length scale design of deformation processes for control of orientation (texture) dependent properties

Abstract

Design of deformation (thermo-mechanical) processes to achieve desired structural response will be addressed. Plastic deformation is assumed to be accommodated through crystallographic slip and reorientation of crystals. Conventional methodologies towards polycrystal plasticity use an aggregate of single crystals and this choice of the aggregate affects the response of the polycrystal. In order to address this issue, a continuum approach will be presented for the representation of polycrystals through an orientation distribution function over the orientation space. In addition, conventional polycrystal plasticity models do not consider strain rate and temperature effects on the mechanical response of a crystal. In this effort, a constitutive framework for thermo-elastic-viscoplastic response will be described along with a coupled macro-micro, fully implicit algorithm [1]. Numerical examples that highlight the benefits of the proposed approach will be detailed. Design/control problems, relevant to industry, and involving microstructure sensitive-design of processes will be addressed. A novel, coupled macro-micro continuum sensitivity analysis [2] has been developed for the thermo-mechanical deformation process and is used in a gradient based optimization framework [3]. The design problems are posed as optimization problems with design variables chosen to characterize macro-scale deformation. Through these complex examples, we aim to show that accurate modeling and control of microstructure-sensitive material response is indeed feasible.