The 7th International Congress on 3D Materials Science (3DMS 2025): Time Resolved 3D Characterization II
Program Organizers: Henry Proudhon, Mines Paris Centre Des Materiaux; Can Yildirim, European Synchrotron Radiation Facility
Wednesday 9:00 AM
June 18, 2025
Room: Platinum Ballroom 2
Location: Anaheim Marriott
Session Chair: Andrew Polonsky, Sandia National Laboratories
9:00 AM Invited
Capturing the Emergence of Hierarchical Microstructures in Metallic Materials: Ashwin Shahani1; 1University of Michigan
Microstructure is the ‘fingerprint’ that identifies the unique characteristics of a material. Oftentimes that microstructure shows a hierarchy of length-scales, from point and line defects at the atomic scale to secondary phases at the mesoscale. This raises an important question about how various classes of defects emerge and interact with each other during processing. In this talk, I will focus on the microstructural complexity of metal matrix nanocomposites and shape memory alloys, highlighting efforts by my group in understanding and controlling that complexity to meet technological demands. Our work is made possible by real-time, three-dimensional imaging with synchrotron x rays, which enables us to obtain key insights on the evolution of microstructure, and ultimately, to test the predictions of simulations and theory. I will also explore future directions at the intersection of multimodal characterization and artificial intelligence to analyze next generation engineering materials and their hierarchical microstructures.
9:30 AM
Watching Real-Time Eutectic Solidification to Understand the Crystal Morphology Formation and Habit Plane Selection: Paul Chao1; Shanmukha Aramanda2; Xianghui Xiao3; Ashwin Shahani2; 1Sandia National Laboratories; 2University of Michigan; 3Brookhaven National Laboratory
Our study utilizes synchrotron transmission x-ray imaging at the nanoscale to observe the eutectic solidification dynamics of the Al-Al3Ni alloy in real-time. This process reveals the simultaneous emergence of two solid crystals from the liquid, forming a periodic pattern influenced by solute diffusion and capillary effects. The investigation focuses on the formation of facets under various freezing conditions, a critical aspect for understanding and technological applications. High-resolution imaging of dynamic interfaces presents challenges, prompting the development of alternative imaging strategies. We discuss how the growth front shapes of the Al-Al3Ni eutectic relate to the 3D shape of Al3Ni crystals in the solid state. Additionally, we explore the orientation relationship and habit planes between solid Al and Al3Ni crystals, using Electron Backscatter Diffraction (EBSD) for quantification. This research provides insights into the microstructural evolution during solidification, emphasizing the interplay between phase transformation dynamics and microstructure development.
9:50 AM
Study of Grain-Scale Plastic Events in Ti-7Al Alloys With Far-Field High-Energy Diffraction Microscopy and Graph Theory: Yuefeng Jin1; Xiongye Xiao2; Peiyu Zhang2; Wenxi Li1; Amlan Das3; Katherine Shanks3; Paul Bogdan2; Ashley Bucsek1; 1University of Michigan; 2University of Southern California; 3Cornell High Energy Synchrotron Source
Although plasticity is traditionally modeled as a smooth process in space and time, in some hexagonal close-packed materials like α-phase titanium-aluminum alloys, plasticity can occur in localized, grain-scale bursts, even before macroscopic yield. These grain-scale plastic events are important for understanding room-temperature creep and dwell fatigue. In this work, we use far-field high-energy diffraction microscopy (ff-HEDM) to characterize such events in a Ti-7Al sample during creep loading. To study the mechanisms, we apply graph analysis, where each node represents a grain, and the edge represent the grain connectivity. We analyze both local features of event-prone regions and global characteristics across the grain network. By examining the feature distributions and changes during loading, we gain insights into the initiation, propagation, and evolution of grain-scale plastic events, enhancing our understanding of how localized deformation contributes to material failure. This work is funded by the NSF STC Center of Complex Particle Systems (COMPASS).
10:10 AM
3D Characterization of Hydrogen-Induced Damage in X70 Steel Using Synchrotron X-Ray Tomography: Victor Okumko1; Thilo Morgeneyer2; Yazid Madi2; Henry Proudhon2; Andrew King1; 1Synchrotron Soleil; 2MINES Paris, PSL University, Centre Des Matériaux, CNRS UMR 7633, Evry, France.
Hydrogen embrittlement significantly degrades the mechanical properties of metals, affecting ductility, fracture toughness, and fatigue resistance. This study examines the initiation and propagation of hydrogen-induced damage in X70 stainless steel, utilizing smooth and round-notched tensile samples to evaluate stress triaxiality effects. High-resolution synchrotron X-ray tomography and Scanning Electron Microscopy were employed to analyse surface and internal damage under varying hydrogen pressures and strain rates. In-situ tensile tests at the PSICHE beamline facilitated simultaneous mechanical testing and imaging. Results from smooth tensile samples indicate that cracks primarily initiate at the surface under moderate strain rates, while low strain rates promote deeper hydrogen diffusion, leading to internal damage. The ongoing investigation of round-notched samples aims to elucidate geometry's role in stress concentrations and hydrogen impact on crack nucleation and growth. These findings will enhance the development of a multiscale numerical model for safer hydrogen infrastructure design under the European project HyWay.
10:30 AM Break
10:50 AM
Dynamics of Individual Dislocations During Plastic Deformation: Felix Frankus1; Adam Cretton1; Sina Borgi1; Albert Zelenika1; Anter El-Azab2; Henning Poulsen1; Grethe Winther1; 1Technical University of Denmark; 2Purdue University
The plasticity of metals is fundamental to manufacturing, yet our understanding of the micromechanics of work-hardening remains incomplete due to complex, multiscale interactions between dislocations. Validating theoretical dislocation interaction models requires time-resolved, 3D experimental datasets that represent bulk behaviour. Recently, Dark-Field X-Ray Microscopy (DFXM) has enabled the imaging of such datasets across hundreds of micrometres within in-situ strained, millimetre-sized specimens. We present DFXM movies of aluminium tensile specimens, capturing dislocation interactions combined with meso-scale structural evolution at low strain levels, including pileups and dislocation boundaries over volumes exceeding several hundred cubic micrometres. Analysis of strain fields around dislocation lines allowed extraction of line directions and Burgers vectors, providing a detailed description of dislocation structure.We tracked a dislocation pileup configuration from formation through rearrangement to dissolution. These identified configurations serve as input for discrete dislocation dynamics simulations, allowing comparisons between experimental observations and predictions for stress fields and dislocation velocities.
11:10 AM
Grain Boundary Migration in Mesoscale Polycrystals: Zipeng Xu1; Robert Suter1; Gregory Rohrer1; 1Carnegie Mellon University
During thermally activated grain growth, the grain boundary migrates to reduce the system's total excess free energy. Although the classical theory describes the migration behavior in bicrystals, recent studies show that this is not the case in polycrystals. In this talk, we will discuss grain boundaries’ migration behavior in polycrystals from impurities and energy anisotropy effects, using two high-energy diffraction microscopy (HEDM) measured polycrystals with multiple time steps. We found that, both on average and locally around the triple junction, grain boundary energy anisotropy affects the grain growth process such that low energy grain boundaries tend to replace and grow at the expense of neighboring high energy grain boundaries. With those observations, we proposed a new mechanism of grain boundary migration, which potentially can explain the inconsistency from the classical theory. The findings suggest the importance of energy anisotropy during grain growth.
11:30 AM
High Speed High-Energy Diffraction Microscopy During Ti64 Dwell Fatigue: Kenneth Peterson1; Kelly Nygren2; Sven E. Gustafson2; Arthur Woll2; Paul Shade3; Mark Obstalecki3; Darren C. Pagan1; 1Pennsylvania State University; 2Cornell High Energy Synchrotron Source; 3Air Force Research Laboratory
Dwell fatigue failure has been proposed to initiate from stress concentrations resulting from accumulated slip during dwell. However, to date, a challenge to determining precise conditions at failure nucleation stem from the difficulty of resolving the transient interplay of deformation mechanisms at appropriate time scales. Fortunately, the next generation of synchrotron-compatible load frames and wide dynamic-range X-ray area detectors have enabled diffraction data collection in situ with unprecedented speed and fidelity. This new capability allows for investigation into 3D deformation processes that had previously been inaccessible, like the subtle evolution of stress that occurs within individual grains during dwell. Here, we utilize these technological advancements to perform far-field high energy X-ray diffraction microscopy (ff-HEDM) continuously within individual dwell periods during dwell fatigue testing of Ti-6Al-4V at room temperature. FF-HEDM measurement times are reduced from approximately 10 minutes to 10 seconds, enabling unprecedented views of microscale deformation behavior during dwell.
11:50 AM
Investigating the Influence of Strain Rate on Hydrogen Embrittlement in Steel Sub-Size Tensile Specimens Using X-Ray 3D Tomography: Luciano Santana1; Victor Okumko2; Andrew King2; Thilo Morgeneyer1; Jacques Besson1; Yazid Madi1; 1Mines Paris PSL - Centre des Matériaux; 2Synchrotron SOLEIL
This study examines the effect of strain rate on hydrogen embrittlement in steel sub-size tensile specimens using X-ray 3D tomography. Tensile specimens were subjected to various strain rates in both air and a 100 bar hydrogen environment, with tests interrupted before fracture. High-resolution tomography revealed strain-rate-dependent differences in damage distribution and orientation. At moderate strain rates, damage initiates from the surface as flat ellipses perpendicular to the specimen's longitudinal axis, indicative of brittle hydrogen-induced cracking, and in the bulk as elongated ellipsoids aligned with longitudinal axis, typical of microvoid coalescence. At low strain rates, hydrogen diffuses more deeply, causing embrittlement throughout the specimen, with brittle damage parallel to the longitudinal axis observed both in bulk and at the surface. This research advances understanding of the mechanical response and damage progression in steel exposed to gaseous hydrogen.