A5047295763- Microstructure and mechanical properties
- Advanced X-ray Imaging Techniques
- Microstructure and Mechanical Properties of Steels
- Nuclear Materials and Properties
- Additive Manufacturing Materials and Processes
- Machine Learning in Materials Science
- Advanced Electron Microscopy Techniques and Applications
- Welding Techniques and Residual Stresses
- Hydrogen embrittlement and corrosion behaviors in metals
- Metallurgy and Material Forming
- Composite Material Mechanics
- High Temperature Alloys and Creep
- Advanced X-ray and CT Imaging
- Nuclear reactor physics and engineering
- Additive Manufacturing and 3D Printing Technologies
- Model Reduction and Neural Networks
- Integrated Circuits and Semiconductor Failure Analysis
- Digital Holography and Microscopy
- Advanced Materials Characterization Techniques
- High-Velocity Impact and Material Behavior
- High-pressure geophysics and materials
- Fatigue and fracture mechanics
- High Entropy Alloys Studies
- Nuclear Physics and Applications
- Metal and Thin Film Mechanics
Los Alamos National Laboratory
2016-2025
Government of the United States of America
2020
Naval Research Laboratory Materials Science and Technology Division
2020
Carnegie Mellon University
2011-2015
Lawrence Livermore National Laboratory
2014
The response of polycrystals to plastic deformation is studied at the level variations within individual grains, and comparisons are made theoretical calculations using crystal plasticity (CP) . We provide a brief overview CP review literature, which dominated by surface observations. motivating question asks how well does represent mesoscale behavior large populations dislocations (as carriers strain). literature shows consistently that only moderate agreement found between experiment...
Scintillators are important materials for radiographic imaging and tomography (RadIT), when ionizing radiations used to reveal internal structures of materials. Since its invention by R\"ontgen, RadIT now come in many modalities such as absorption-based X-ray radiography, phase contrast imaging, coherent diffractive high-energy X- $\gamma-$ray radiography at above 1 MeV, computed (CT), proton (IT), neutron IT, positron emission (PET), electron muon tomography, etc. Spatial, temporal...
The evolution of the crystallographic orientation field in a polycrystalline sample copper is mapped three dimensions as tensile strain applied. Using forward-modeling analysis high-energy X-ray diffraction microscopy data collected at Advanced Photon Source, ability to track intragranular variations demonstrated on an ∼2 µm length scale with ∼0.1° precision. Lattice rotations within grains are tracked between states ∼1° Detailed presented for cross section before and after ∼6% strain....
Abstract The nucleation and propagation of dislocations is an ubiquitous process that accompanies the plastic deformation materials. Consequently, following first visualization over 50 years ago with advent transmission electron microscopes, significant effort has been invested in tailoring material response through defect engineering control. To accomplish this more effectively, ability to identify characterize structure strain external stimulus vital. Here, using X-ray Bragg coherent...
We present a novel adaptive machine-learning based approach for reconstructing three-dimensional (3D) crystals from coherent diffraction imaging. represent the using spherical harmonics (SH) and generate corresponding synthetic patterns. utilize 3D convolutional neural networks (CNNs) to learn mapping between volumes SH, which describe boundary of physical they were generated. use CNN-predicted SH coefficients as initial guesses, are then fine-tuned model-independent feedback improved...
We present a physics-constrained neural network (PCNN) approach to solving Maxwell’s equations for the electromagnetic fields of intense relativistic charged particle beams. create 3D convolutional PCNN map time-varying current and charge densities J(r, t) ρ(r, vector scalar potentials A(r, φ(r, from which we generate according equations: B = ∇ × A E −∇φ − ∂A/∂t. Our PCNNs satisfy hard constraints, such as · 0, by construction. Soft constraints push φ toward satisfying Lorenz gauge.
With the advent of additive manufacturing, manipulation typical microstructural elements such as grain size, texture, and defect densities is now possible at a faster time scale. While processing–structure–property relationship in manufactured metals has been well studied over past decade, little work done understanding how this process affects dynamic behavior materials. We postulate that manufacturing can be used to alter material microstructure enhance its strength. In work, 316L...
A microstructure-based capability for forecasting microcrack nucleation in the nickel-based superalloy LSHR is proposed, implemented, and partially verified. Specifically, gradient crystal plasticity applied to finite-element models of experimentally measured, 3D microstructure wherein a known have nucleated along coherent Σ3 boundary. The framework used analyze this particular event conduct an extensive grain boundary analysis study, results which underpin importance that elastic anisotropy...
Abstract Microstructure-aware models are necessary to predict the behavior of material based on process knowledge or extrapolate mechanical properties materials environmental conditions which not easily reproduced in laboratory, e.g. , nuclear reactor environments. Elemental Ta provides a relatively simple BCC system develop microstructural understanding deformation processes can then be applied more complicated alloys. In situ neutron diffraction during compressive and subsequent heat...