Prediction of tensile stiffness and strength of Ti-6Al-4V using instantiated volume elements and crystal plasticity

Based on simulations of tensile tests, the macroscopic stiffness and strength of the a phase of Ti-6Al-4V are estimated. Sets of virtual samples are instantiated using characterization data from three-dimensional electron back-scattered diffraction (EBSD) scans collected with the TriBeam microscope and local properties extracted from in situ loading high-energy x-ray diffraction (HEXD) experiments. The simulations use a crystal-scale finite element framework to compute the mechanical response of the virtual samples under tensile loading. From the simulation data, mechanical properties are extracted from volume elements ranging in size from a fraction of the gage section to its entire length. To detect macroscopic yield, a flood-fill algorithm is used to identify a zone of plastically deformed finite elements extending through a volume element. Trends in the estimated properties as functions of the volume element size are examined. The lower bound of volume element size necessary to replicate experimentally measured macroscale properties is indicated. The technique and results provide a guideline for estimating macroscale property values in components designed with size smaller than the lower bound due to constraint. (C) 2018 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.