Neutron and X-ray Scattering in Materials Science: Techniques, Instrumentation, and Facilities
Sponsored by: TMS Functional Materials Division, TMS: Chemistry and Physics of Materials Committee
Program Organizers: Michael Manley, Oak Ridge National Laboratory; Chen Li, University of California-Riverside; Jennifer Niedziela, Oak Ridge National Lab; Hillary Smith, Swarthmore College
Tuesday 2:30 PM
March 21, 2023
Room: Aqua 311B
Location: Hilton
Session Chair: Jennifer Niedziela, Oak Ridge National Laboratory
2:30 PM Invited
Neutron Scattering Opportunities for Materials Science at Oak Ridge National Laboratory: Georg Ehlers1; Kenneth Littrell1; 1Oak Ridge National Laboratory
Neutron scattering is an important and impactful experimental technique for materials science. Oak Ridge National Laboratory operates two neutron sources as user facilities, HFIR and SNS. These sources offer peer-reviewed access to beam time with several instruments optimized for the needs of the materials community. A third source is currently being planned and designed, the SNS Second Target Station. This presentation highlights some recent instrument upgrades and future plans for new instruments.
3:00 PM Invited
In Situ High Pressure Neutron Scattering for Materials Characterization: Bianca Haberl1; Mary-Ellen Donnelly1; Malcolm Guthrie1; Garrett Granroth1; Reinhard Boehler1; 1Oak Ridge National Laboratory
While high pressure enables the formation of novel materials with unique properties, in situ neutron scattering gives unique insight into their formation mechanisms and characteristics. In situ high pressure neutron scattering has, however, been limited in maximum pressures due to large sample volumes required. Recent developments at the Spallation Neutron Source aim to overcome these limitations and I will highlight two recent key breakthroughs here. First, high pressure spectroscopy was performed at the ARCS spectrometer in a Paris-Edinburgh cell up to 16 GPa. Interesting insights into the pressure-induced metallization of germanium and the subsequent formation of a useful metastable polymorph with desirable electronic properties are discussed. Secondly, neutron diamond anvil cell developed for the SNAP diffractometer and capable of megabar diffraction, are used to characterize metal superhydrides under pressure. This is of particular relevance in the understanding of record-breaking high Tc superconductivity in superhydrides and recent results will be reported.
3:30 PM
Initial Instruments at the Second Target Station: Leighton Coates1; 1Oak Ridge National Laboratory
The Second Target Station (STS) of the Spallation Neutron Source (SNS) will provide intense neutron beams with smaller cross sections to explore samples of newly discovered or synthesized materials under extreme conditions and enable simultaneous measurements of hierarchical architectures across an unprecedented range of length scales. The science enabled by these instruments will provide new capabilities to study quantum materials, soft matter, energy materials, biology, and structural materials. In this talk, the eight selected instrument concepts will be introduced, and an update on the progress of the STS project will be provided.
3:50 PM
PIONEER and VERDI, Two Next Generation Neutron Diffractometers for Materials Science at the Second Target Station: Yaohua Liu1; 1Oak Ridge National Laboratory
The Second Target Station (STS) at the Spallation Neutron Source (SNS) will provide a world-leading capability in high-brightness cold neutron beams with broad energy/wavelength ranges to meet challenges at the frontiers of matter and energy. Two next-generation neutron diffractometers - PIONEER and VERDI - are currently under design using advanced optics to leverage the STS source characteristics. These instruments will offer new science opportunities in materials science and technology that can lead to breakthrough discoveries. PIONEER is a high Q-resolution, single-crystal neutron diffractometer capable of significantly lowering the sample size barrier for neutron diffraction. VERDI is a wide-wavelength bandwidth diffractometer with full polarization analysis capabilities for complex magnetic structure studies in powders and single crystals. Both instruments will support various sample environments, including low and high temperatures, magnetic fields, and pressure. We will present the instrument development status and introduce their transformative capabilities using virtual experiment examples.
4:10 PM Break
4:25 PM
Operando Neutron Diffraction Reveals Insights into Transient Phases and Residual Stresses during Directed Energy Deposition Additive Manufacturing: Chris Fancher1; Kyle Saleeby1; Ke An1; James Haley1; Guru Madireddy1; Thomas Feldhausen1; Yousub Lee1; Dunji Yu1; Clay Leach1; Alex Plotkowski1; 1Oak Ridge National Laboratory
Additive Manufacturing (AM), often called 3D printing, offers the unique opportunity to transform how materials are consolidated into bulk 3D structures. The localized melt strategies in metal AM introduce non-equilibrium thermal conditions that can affect the microstructure and phase evolution in as-fabricated parts. ORNL has developed an AM sample environment to study transient phases and bulk stress evolution during metal DED using the engineering diffractometer VULCAN-X at the Spallation Neutron Source. This paper will present the system's system capabilities by capturing the phase evolution during deposition of low-temperature transition and mild steels in operando. Differences in the temperature dependences of phase transitions significantly impact as-fabricated residual strains and stresses. Measured operando diffraction data provide critical information needed for material model validation mechanics, including the use of diffraction data as a bulk temperature probe.
4:45 PM
Polychromatic Multiplexing Stress-strain Diffractometer: Sean Fayfar1; Boris Khaykovich1; Theodore Cremer2; 1Massachusetts Institute of Technology; 2Adelphi Technology
The development of new materials for advanced technologies such as electric cars and clean energy production requires new characterization techniques, especially with in-situ measurements during synthesis. Neutron scattering techniques have gained in popularity with the development and improvements of beamline instruments at national facilities. Current engineering beamlines with stress-strain diffractometers require long measurement times due to small gauge volumes in samples. We present our development of a stress-strain diffractometer intended to be optimized for improved efficiency compared with current designs. The diffractometer will utilize a polychromatic beam to illuminate all the lattice planes within the sample at a fixed angle and focusing bent-perfect silicon analyzers placed after the sample. Silicon analyzers are transparent to neutrons which allows the placement of subsequent analyzers for multiplexing capabilities. We will present our results from both experimental testing and ray-tracing simulation and report on the current state of the construction at the MIT Reactor.
5:05 PM
Coded Apertures for Depth Resolved Diffraction: Dina Sheyfer1; Doga Gursoy1; Wenjun Liu1; Jon Tischler1; Michael Wojcik1; 1Argonne National Laboratory
We develop a rapid data acquisition and reconstruction method to image the internal structure of crystalline materials using non-destructive X-ray Laue diffraction microscopy. Our method relies on scanning a coded-aperture across the diffracted beams, and a decoding algorithm to extract Laue patterns as a function of depth along the incident illumination path. This method provides rapid access to full diffraction information at sub-micrometer volume elements in bulk materials and thus can resolve locally in 3D crystal structure, its orientation and strain. Here we present the underlying theory and demonstrate the utility of this approach with micrometre-resolution depth resolving measurements of grain orientations and sizes in polycrystalline Nickel foil.
5:25 PM
Scalable Rietveld Refinements of Diffraction: Daniel Savage1; Christopher Biwer1; Michael McKerns1; Cynthia Bolme1; Sven Vogel1; 1Los Alamos National Laboratory
Diffraction experiments often result in tens to thousands of patterns from which information can be extracted ranging from microstructure to equation of state. The extraction happens by fitting models of the diffraction process which describe the instrument (e.g. sample-to-detector distances and angles), the sample’s crystal structure (e.g. crystallographic space group and lattice parameters), and the microstructure (e.g. phase fractions and texture). Finding the set of parameters that best describes a measurement is hard to do in a robust way without expert intervention and in a way that leverages parallel resources (critical for real-time analysis). We will demonstrate how complex Rietveld of in-situ shocked Titanium can be broken down into a limited decision tree and a set of multilevel optimization schemes. A newly-developed opensource python scripting framework for MAUD Rietveld software (MILK) will be presented with a new python Rietveld optimization package (Spotlight) which together enable the scalable Rietveld optimization strategy.
5:45 PM
Evaluation of Boron Carbide’s Full Elasticity Tensor via Thermal Diffuse X-ray Scattering: Arezoo Zare1; B. Wehinger2; A. Mirone2; D.J. Magagnosc3; M.R. He1; M. Straker4; M. Spencer4; T.C. Hufnagel1; K.T. Ramesh1; 1Johns Hopkins University; 2European Synchrotron Radiation Facility; 3Army Research Laboratory; 4Morgan State University
As an ultrahard and lightweight material with high Hugonoit elastic limit, boron carbide is a promising candidate for protective applications against impact conditions. Knowledge of the elasticity tensor is essential for describing elastic waves/sound velocities in boron carbide and is also an important input parameter for multi-scale models that describe the material’s performance in extreme dynamic environments. Because of the strong anisotropy in the elasticity of boron carbide, which originates from its rhombohedral crystal lattice with trigonal symmetry, it is crucial to obtain the full elasticity tensor without making simplifying assumptions about the crystal symmetry. In the present work, monochromatic x-rays are used to study the elastic anisotropy of B4.9C single crystals. Measurements of thermal diffuse scattering in the proximity of Bragg reflections are performed at two temperatures and a model-free data analysis approach is employed to evaluate the 6 elastic constants of boron carbide for the first time.