Mechanical Response of Materials Investigated through Novel In-situ Experiments and Modeling: Poster Session
Sponsored by: TMS Structural Materials Division, TMS Functional Materials Division, TMS: Advanced Characterization, Testing, and Simulation Committee, TMS: Thin Films and Interfaces Committee
Program Organizers: Saurabh Puri, VulcanForms Inc; Amit Pandey, Lockheed Martin Space; Dhriti Bhattacharyya, Australian Nuclear Science and Technology Organization; Dongchan Jang, Korea Advanced Institute of Science and Technology; Shailendra Joshi, University of Houston; Minh-Son Pham, Imperial College London; Jagannathan Rajagopalan, Arizona State University; Robert Wheeler, Microtesting Solutions LLC; Josh Kacher, Georgia Institute of Technology
Tuesday 5:30 PM
March 21, 2023
Room: Exhibit Hall G
Location: SDCC
L-51: Development and Applications of a Fiber-based Instrument for In-situ Thermal Property Measurements: Zilong Hua1; Robert Schley1; Colby Jensen1; Austin Fleming1; Jorgen Rufner1; Michael Short2; David Carpenter3; David Hurley1; 1Idaho National Laboratory; 2MIT; 3MIT nuclear reactor laboratory
The thermal conductivity of nuclear fuels is a critical physical property that is directly related to reactor efficiency and safety. During the reactor operation, all sorts of microstructure defects will be generated by neutron irradiation and significantly reduce the thermal conductivity of fuels. Currently, experimental efforts to capture such thermal conductivity degradation is primarily through post-irradiation-examination (PIE). It has been speculated that point defects may anneal or cluster into larger scale defects prior to PIE, making the ex-situ measured properties different from the ones measured in-situ. Here we present the latest progress of the development and deployment of a fiber-based photothermal radiometry instrument to in situ measure thermal conductivity of benchmark samples. A similar instrument to be deployed in additive/advanced manufacturing apparatus is also under developing with the purpose to measure thermal properties in the real-time manner, which can be used as an index of the microstructure evolution.
Cancelled
Forward Model Based Strain Analysis in Highly Deformed Metallic Systems Using EBSD Patterns: Chenxi Yu1; Marc De Graef1; 1Carnegie Mellon University
Electron backscatter diffraction (EBSD) has in recent years become a quantitative technique for the analysis of local deformations in crystalline materials; the determination of local orientation changes and strains within a material can provide insights leading to an increased understanding of the properties of deformed materials. Detection of these small lattice rotations and strains requires an analysis capability that can robustly handle low quality EBSD patterns. In this project, we address this issue by improving the EBSD modality by means of whole pattern matching and performing large area low voltage insitu heating experiments on samples that have undergone a carefully controlled amount and mode of deformation. This combination will make it possible to study abnormal sub-grain growth at the early stages of recrystallization process. Our work may provide an efficient approach for improving the spatial resolution of EBSD and more advanced EBSD pattern simulation tools.
L-67: KRaStk – A Multi-scale Toolkit to Compute Fibrous Material Properties: Adnan Taqi1; Mujan Seif1; Matthew Beck1; 1University of Kentucky
Fiber based ablative materials are used in thermal protection systems (TPS) for atmospheric entry of spacecrafts. Connecting macro-scale bulk properties to underlying micro-structural features in these materials is complicated by the intrinsic complexity and randomness of their porous structure. To address this issue—linking complex and random micro-structure to bulk effective properties—we have developed the Kentucky Random Structures Toolkit (KRaSTk), a high-throughput approach to generate and compute properties of model representative volume elements (mRVEs). mRVEs are generated from a physics-based geometric seed description that captures the structure and complexity of fibrous materials. FEM calculations of the properties of many mRVEs allow determination of bulk effective properties, probability distributions of local properties, and structure-property relationships relating specific local structural features to bulk effective properties. We describe and demonstrate KRaSTk capabilities by exploring the structure-property relationships governing fiber based TPS materials, particularly the role of fiber-fiber bonding, fiber bending and sagging.
Ligament Aspect Ratio Effects on Elastic Properties of Porous Network Materials: Naji Mashrafi1; Ryan Griffith1; Mujan Seif1; Matthew Beck1; 1Department of Materials Engineering
Porous network materials are challenging to model due to their inherent complexity and randomness. The recently developed Kentucky Random Structures Toolkit (KRaSTk) implements a high-throughput approach to generate and compute properties of model representative volume elements (mRVEs) based on physics-based geometric seed descriptions capturing relevant structural complexity. Using this toolkit we have computed bulk effective properties, and distribution of length-scale dependent local properties, of porous network structures as a function of aspect ratio of connecting ligaments. Results suggest that changes in aspect ratio of ligaments do affect the stiffness of the material, but this effect cannot be separated from changes in the reduced density of the porous material. These results demonstrate the potential of the KRaSTk approach for exploring structure-property relationships of complex, randomly-structured materials.
L-52: Micromechanics, Kleindiek Manipulators for Increased Flexibility: Olof Baecke1; Ren Qiu1; Magnus Colliander1; 1Chalmers University of Technology
Two limitations that most conventional nanoindenters labour under is that force can only be applied in one direction and a specimen can only be approached along the direction of motion of the actuator of the indenter. These limitations will be a problem if a situation calls for measuring in a plane perpendicular to the axis of actuation. One solution to this is to use a micromanipulator instead for micromechanical testing in-situ. A micromanipulator permits movement in three dimensions for a probe and makes approaching and performing tests on a feature of interest much more flexible. However, the increase in flexibility will lead to worse stiffness and precision. In this work, the possibility of performing micromechanical testing in a scanning electron microscope using a micromanipulator has been explored. Two different tests were performed, cyclic bending of cantilevers and bending of micropillars. Complementary measurements for both tests were performed using a nanoindenter.
L-53: Modeling of the Bending Behavior to Study Nested-Cylinder Structure in Spicules: Olivia Lowe1; Michael Melly1; Alyssa Napora1; Christian Peco1; Fariborz Tavangarian1; 1Pennsylvania State University
The spicule structure of the Euplectella aspergillum sponge (EA) looks promising in the search for mechanical enhancements of brittle materials. Researchers have explored how the various structural levels of the EA affect the properties of the material. Specifically, the nested-cylinder structure of the EA’s spicules increases the strength and toughness of the sponge. However, there is limited research on this structural level of the sea sponge. This research uses finite element analysis (FEA) to model the spicule structure in COMSOL, setting the stage for further research into this bio-inspired material. The results of the initial bending tests prove this procedure of analysis is useful in the study of the spicule structure.
L-54: Tensile Deformation of Polycrystalline Pure Cobalt Studied by In-situ High Energy X-ray Diffraction: Takumi Suzumura1; Si Gao1; Shuhei Yoshida1; Nobuhiro Tsuji1; 1Kyoto University
Pure cobalt is well-known to have HCP structure at room temperature. However, small amount of high temperature FCC phase of pure cobalt has been always found to retain at room temperature, which could transform to HCP phase upon subsequent deformation. In this study, tensile tests with in-situ X-ray diffraction were performed at SPring-8 in Hyogo, Japan on a polycrystalline pure cobalt having HCP matrix phase and a few amounts of retained FCC phase to investigate the role of FCC to HCP transformation in the tensile deformation. It was found that the internal stress in the FCC phase quickly leveled off after yielding while that in the HCP phase increased continuously during deformation. The results suggested that the strain hardening of the specimen was mostly contributed by the HCP phase. The detailed analysis on the diffraction profiles and microstructure evolution will be discussed in the presentation.
Variation in the Bulk Elasticity of Nanoporous Materials from Solid Structure Mechanical Properties: Ryan Griffith1; Naji Mashrafi1; Matthew Beck1; 1University of Kentucky
The nanoscale mechanical properties of porous materials have long been questioned as representatives of the bulk properties on the macroscale and vice versa. As solid structures become porous, the alignment of ligaments and voids within the matrix contributes to the overall mechanical properties. This study aims to observe whether or not the bulk stiffness and Poisson’s ratio of a solid material can serve as predictors of the elasticity of a porous structure. It was found that variation in the mechanical properties resulted in a positively linear relationship with the elasticity.