5th International Congress on 3D Materials Science (3DMS 2021): Process Microstructure Properties II
Program Organizers: Dorte Juul Jensen, Technical University of Denmark; Erica Lilleodden, Fraunhofer Insitute for Microstructure of Materials and Systems (IMWS); Scott Barnett, Northwestern University; Keith Knipling, Naval Research Laboratory; Matthew Miller, Cornell University; Akira Taniyama, The Japan Institute of Metals and Materials; Hiroyuki Toda, Kyushu University; Lei Zhang, Chinese Academy of Sciences

Thursday 2:10 PM
July 1, 2021
Room: Virtual D
Location: Virtual

Session Chair: Yubin Zhang, Technical University of Denmark

Investigation of Grain Boundary Behavior Using Crystal Based Finite Element Method on a 3D Characterized Oligocrystal Aluminum: Eralp Demir1; 1Sabanci University
    Grain boundary behavior has been studied up to date due to its complex behavior; acts as a sink or a source, low-angle grain boundaries allowing dislocation transmission, etc. In this study a columnar-like aluminum sample with large grain sizes reaching over millimeters was fully characterized by using EBSD technique from the two opposite side surfaces. The sample was tensile tested and strains were measured using DIC method. To better understand grain boundary effects, crystal-based finite element models with three different constitutive laws were developed including a phenomenological model, dislocation density based model and a non-local flux based dislocation density model. The amount of grain boundary strengthening was found to be a function of the amount of slip inside grains, misorientation between the grains, and grain boundary normal. Non-local dislocation flux based model revealed significantly better strain distributions near the grain boundary, even though the sample scale was relatively large.

Microstructures and Properties of As-Cast Al2.7CrFeMnV, Al2.7CrFeTiV, and Al2.7CrMnTiV High Entropy Alloys: Keith Knipling1; Patrick Callahan1; Richard Michi2; David Beaudry3; 1Naval Research Laboratory; 2Northwestern University; 3University of Florida
    High entropy alloys (HEAs) typically contain five or more principal elements in nearly equiatomic proportions, significantly expanding the composition space and achievable properties of novel metallic materials. Here we present the complex microstructures of as-cast Al2.7CrFeMnV, Al2.7CrFeTiV, and Al2.7CrMnTiV HEAs. All alloys are predominantly body-centered cubic (BCC). Al2.7CrFeMnV is single-phase BCC with lattice parameter (a) of 0.2968 nm. Al2.7CrFeTiV is multiphase, with a high volume fraction of Al-rich G-phase precipitates and Laves phases in a BCC matrix (a = 0.3006 nm). Al2.7CrMnTiV contains micron-scale AlTi (L10) precipitates as well as coherent, nanoscale cuboid B2 precipitates in a BCC matrix (a = 0.3946 nm). In each of the alloys, atom-probe tomography is used to visualize the nanoscale microstructures in three dimensions and assess atomic-scale clustering and ordering. These experimental results are compared with the equilibrium phases predicted by thermodynamic modeling.

Investigation of Microstructural Evolution during Compression of Ni Foam Using Micro-CT and FEM: Jaehyung Cho1; Jun-Ho Lee1; Geon Young Lee1; Jong-Joo Rha1; 1Korea Institute of Materials Science
    Metal foams have been widely used in many applications ranging from weight-saving structures and heat exchange to functional applications, due to low density, high ratio of weight to strength, and large surface area. In this study, mechanical responses and microstructural evolution of porous Ni with approximately 92% porosity are investigated using micro-CT and finite element method. During uni-axial compression, flow curves consist of linear elastic, quasi-plateau and densification stages. Using micro-CT, three-dimensional model was reconstructed and was used for FE modeling of compression. Stress relaxation observed near transition between linear elastic and quasi-plateau stages was associated with buckling of narrow ligament structures. Thick ligaments revealed high stress distribution and few buckling. Similar pore distribution but thicker ligament resulted in decrease in porosity and little stress relaxation. With increase in porosity, energy absorption decreased but ideal efficiency of energy absorption increased. The stress relaxation somewhat improved ideal efficiency of energy absorption.

OOF: Modular, Extensible Finite Element Analysis for Materials Science : Andrew Reid1; 1National Institute of Standards and Technology
    The OOF object-oriented finite element software, developed at the National Institute of Standards and Technology, provides an interactive finite-element modeling tool which packages sophisticated mathematical capabilities with a user-interface that speaks the language of materials science. Users can construct finite-element meshes directly from material images in either 2D or 3D, and then perform virtual experiments to explore structure-property relationships within the microstructure, including effective properties. The 3D version of the software has recently been extended to include crystal plasticity, demonstrating the flexibility of the software architecture. The development team is also interested in integrating this software into emerging data-driven analytical and modeling workflows, ingesting constitutive data from on-line materials data repositories, with the ultimate aim of particpating in a closed materials optimization loop.