Dependence of Initial Grain Orientation on the Evolution of Anisotropy in FCC and BCC Metals Using Crystal Plasticity and Texture Analysis

by Daniel Selvakumar Raja

Institution: Southern Illinois University at Edwardsville
Year: 2015
Keywords: Mechanical engineering; Materials science
Posted: 02/05/2017
Record ID: 2083361
Full text PDF: http://pqdtopen.proquest.com/#viewpdf?dispub=1597933


Abundant experimental analyses and theoretical computational analyses that had been performed on metals to understand anisotropy and its evolution and its dependence on initial orientation of grains have failed to provide theories that can be used in macro-scale plasticity. Ductile metals fracture after going through a large amount of plastic deformation, during which the anisotropy of the material changes significantly. Processed metal sheets or slabs possess anisotropy due to textures produced by metal forming processes (such as drawing, bending and press braking). Metals that were initially isotropic possess anisotropy after undergoing forming processes, i.e., through texture formation due to large amount of plastic deformation before fracture. It is therefore essential to consider the effect of anisotropy to predict the characteristics of fracture and plastic flow performances in the simulation of ductile fracture and plastic flow of materials. Crystal plasticity simulations carried out on grains at the meso-scale level with different initial orientations (ensembles) help to derive the evolution of anisotropy at the macro-scale level and its dependence on initial orientation of grains. This paper investigates the evolution of anisotropy in BCC and FCC metals and its dependence on grain orientation using crystal plasticity simulations and texture analysis to reveal the mechanics behind the evolution of anisotropy. A comparison of anisotropy evolution between BCC and FCC metals is made through the simulation, which can be used to propose the theory of anisotropy evolution in macro-scale plasticity. Keywords: ensembles; grains; initial orientation; anisotropy; evolution of anisotropy; crystal plasticity; textures; homogeneity; isotropy; inelastic; equivalent strain