6th International Congress on 3D Materials Science (3DMS 2022): 4D Data Analysis IV: Fatigue/Fracture
Program Organizers: Dorte Juul Jensen, Technical University of Denmark; Marie Charpagne, University of Illinois; Keith Knipling, Naval Research Laboratory; Klaus-Dieter Liss, University of Wollongong; Matthew Miller, Cornell University; David Rowenhorst, Naval Research Laboratory
Wednesday 8:20 AM
June 29, 2022
Room: Capitol B
Location: Hyatt Regency Washington on Capitol Hill
Session Chair: Dorte Jensen, DTU Risų
8:20 AM Invited
Ductile Damage UnderSshear Loading: Mechanisms Analysis Through In-situ Laminography Experiments for Dual-phase Steel and Aluminum Alloys: Dirk Mohr1; Thomas Tancogne-Dejean1; 1ETH Zurich
The nucleation, evolution and coalescence of voids is the well-established mechanism leading to ductile fracture under tension-dominated loading conditions. From a theoretical point of view, the same mechanism also applies to shear-dominated loading conditions. Using in-situ X-ray synchrotron laminography experiments, the failure mechanisms of two modern engineering materials (AA2024-T3 and FB600 steel) are investigated under low stress triaxialities. The mesostructural evolution is reconstructed through multiple loading steps, using 2D Digital Image Correlation of projected volumetric data. For both materials, it is found that preexisting second-phase particles acts as nucleation site through either cracking or debonding. The nucleated voids growth to micro-crack like feature leading to final failure. Fracture mechanisms are proposed based on these observations and assessed with representative volume element simulations, pointing towards the formation of a shear localization band during the final loading step.
8:50 AM
Searching for Life-limiting Localized Deformation in Inconel-718 using In-situ Cyclic Loading and High Energy X-rays: Dalton Shadle1; Kelly Nygren1; Matthew Miller1; 1Cornell University
To understand complex phenomena such as fatigue crack initiation in a ductile polycrystal, ideally, we would probe everywhere, all the time. Unfortunately, there is a trade-off between temporal and spatial resolution in 3D experimental techniques. Characterizations which prioritize temporal resolution must sacrifice the spatial resolution or dimensionality of data and can lose direct access to important microstructural features tied to mechanisms of interest. In this work, we employ spatially-resolved electron characterization techniques to inform time-resolved high-energy X-ray diffraction microscopy (HEDM) characterizations to identify grains exhibiting localized-deformation inside (Gremlins) through a signature of localized-deformation in an Inconel-718 sample subjected to fully reversed cyclic loading. We construct this signature by correlating the shape of single grain orientation distributions with high gradients of localized-deformation within a grain. With this signature, we focus on the evolution of stress and orientation of individual Gremlins to understand the potential for fatigue crack initiation within the material.
9:10 AM
Sub-grain-level Fatigue Crack Growth Insights via High Energy X-ray Diffraction Microscopy: William Musinski1; Paul Shade1; Mark Obstalecki1; David Menasche2; Joel Bernier3; Sirina Safriet4; Peter Kenesei5; Jun-Sang Park5; 1US Air Force Research Laboratory; 2Hamiltonian Group; 3Lawrence Livermore National Laboratory; 4University of Dayton Research Institute; 5Argonne National Laboratory
To advance microstructure-based fatigue lifing tools for aircraft engine components, crack growth data obtained at the relevant (microstructure) scale is needed. Towards this end, we present results from a high energy X-ray diffraction microscopy (HEDM) experiment coupling near field HEDM, far field HEDM, micro-computed tomography, and in-situ cyclic loading to study the evolution of sub-grain-level fatigue crack growth within a Ni-base superalloy at room temperature. A starter focused-ion beam notch was introduced within the specimen to concentrate damage within the characterized microstructure area of interest. Periodic micro-computed tomography and far field HEDM measurements were used to monitor the sporadic growth of the primary crack front, void formation in front of the crack front, and grain-level strains ahead of the crack front. Insightful correlations between 3D crack path, local microstructure, and grain boundary effect are elucidated and implications for microstructure-based fatigue lifing tools are discussed.
9:30 AM
Quantifying Microscale Drivers for Fatigue Failure via Coupled Synchrotron X-ray Characterization and Simulations: Sven Gustafson1; Wolfgang Ludwig2; Paul Shade3; Diwakar Naragani1; Darren Pagan4; Phil Cook2; Can Yildirim2; Carsten Detlefs2; Michael Sangid1; 1Purdue University; 2European Synchrotron Radiation Facility; 3Air Force Research Laboratory; 4Cornell High Energy Synchrotron Source
During cyclic loading, localization of intragranular deformation due to crystallographic slip acts as a precursor for crack initiation, often at coherent twin boundaries. A suite of high-resolution synchrotron X-ray characterizations, coupled with a crystal plasticity simulation, was conducted on a polycrystalline nickel-based superalloy microstructure near a parent-twin boundary in order to understand the deformation localization behavior of this critical, 3D microstructural configuration. For the first time, dark-field X-ray microcopy was spatially linked to high energy X-ray diffraction microscopy and X-ray diffraction contrast tomography in order to quantify, with cutting-edge resolution, an intragranular misorientation and high elastic strain gradients near a twin boundary. These observations quantify the extreme sub-grain scale stress gradients present in polycrystalline microstructures, which often lead to fatigue failure.
9:50 AM Break
10:10 AM
3D Aspects of Ice Compressive Failure During Ice-structure Interaction: Rocky Taylor1; 1Memorial University
During interactions between ice in the ocean and engineered structures, ice compressive failure plays a dominant role in governing local ice loads transmitted to the structure. Such ice is at a high homologous temperature and for interaction rates of interest for many engineering applications, the ice is highly brittle. Consequently, spalling fractures localize the contact into regions known as high pressure zones (hpzs) which typically comprise about 10% of the nominal interaction area and transmit about 80% of the loads. The processes that govern ice material behaviour in these hpzs result from a complex interplay between discrete fracture and continuum damage mechanisms associated with microcracking, dynamic recrystallization and localized pressure melting. In this paper, the three-dimensional dynamic nature of the physical phenomena that govern ice pressures during such interactions are reviewed, recent experimental results are discussed and challenges for measuring and modelling these processes are explored.
10:30 AM
3D Characterization of Grain-scale Cyclic Twinning and Detwinning in Magnesium Alloys using High Energy X-ray Diffraction: Duncan Greeley1; Mohammadreza Yaghoobi; Katherine Shanks2; Darren Pagan; Veera Sundararaghavan; John Allison; 1University of Michigan; 2Cornell High Energy Synchrotron Source, Cornell University
Magnesium is a promising material for lightweight structural parts in the transportation industries due to its low density and high specific strength. Cyclic deformation is a primary concern for structural components, and accurately modelling cyclic mechanical response in magnesium alloys requires a more detailed understanding of the impact of twinning on grain-scale deformation. In this study, we have developed an automated reconstruction procedure for identifying and tracking 3D grain-scale twin evolution in magnesium alloys using combined far-field and near-field High Energy X-Ray Diffraction Microscopy (HEDM). Twinning and detwinning were characterized using this reconstruction procedure in pure magnesium, Mg-4wt.%Al, Mg-7.5wt.%Y, and Mg-2.4wt.%Nd during single cycle compression-tension displacements experiments at the Cornell High Energy Synchrotron Source (CHESS). The impact of twinning and detwinning on the evolution of grain-resolved deformation and the role of binary alloying on twin activity were investigated, and grain-scale mechanical response was modelled using crystal plasticity finite element methods.
10:50 AM
3D Characterization of Damage in Spalled Tantalum: Toby Francis1; Paul Rottmann2; Andrew Polonsky1; Marie-Agathe Charpagne1; McLean Echlin1; William Lenthe3; Veronica Livescu4; David Jones4; George Gray4; Marc De Graef3; Tresa Pollock1; 1University of California, Santa Barbara; 2University of Kentucky; 3Carnegie Mellon University; 4Los Alamos National Laboratory
The use of electron backscatter diffraction (EBSD) to characterize damaged materials can provide significant insights into the microstructural mechanisms underlying failure. However, properly characterizing the nature of failure initiation sites requires three-dimensional data with high spatial resolution. In this talk, we discuss the use of a TriBeam multi-modal imaging experiment on plate-impacted tantalum which underwent partial spallation. Advancements in the processing of 3D-EBSD data, namely advanced pattern indexing and distortion correction techniques, will be shown to be crucial for successful characterization of heavily-deformed materials. The resulting statistics regarding the microstructural neighborhoods and plastic deformation surrounding voids provide critical insights into void nucleation and growth mechanisms. In particular, these analyses point towards cavitation as the micromechanism for ductile spallation in high-purity metals. Quadruple points will be shown to be crucial to understanding failure, exemplifying the necessity for 3D characterization of failed specimens.
11:10 AM Break