Characterization of Minerals, Metals and Materials 2021: Advanced Microstructure Characterization
Sponsored by: TMS Extraction and Processing Division, TMS: Materials Characterization Committee
Program Organizers: Jian Li, CanmetMATERIALS; Mingming Zhang, Baowu Ouyeel Co. Ltd; Bowen Li, Michigan Technological University; Sergio Monteiro, Instituto Militar de Engenharia; Shadia Ikhmayies, The University of Jordan; Yunus Kalay, Middle East Technical University; Jiann-Yang Hwang, Michigan Technological University; Juan Escobedo-Diaz, University of New South Wales; John Carpenter, Los Alamos National Laboratory; Andrew Brown, Devcom Arl Army Research Office; Rajiv Soman, Eurofins EAG Materials Science LLC; Alex Moser, Naval Research Laboratory
Monday 2:00 PM
March 15, 2021
Room: RM 15
Location: TMS2021 Virtual
Session Chair: John Carpenter, Los Alamos National Laboratory; Mingming Zhang, ArcelorMittal Global R&D
2:00 PM
A Comparison between ZnO Cauliflowers on Glass and Aluminum Substrates: Shadia Ikhmayies; 1
Zinc oxide (ZnO) thin films are produced by the spray pyrolysis method on glass and Aluminum substrates. The films are characterized by X-ray diffraction (XRD), scanning, electron microscopy (SEM), and X-ray energy dispersive spectroscopy (EDS). The SEM images of some films in both cases showed caulflowers. A comparison between these two sets of films is performed and discussed.
2:20 PM
Plastic Behavior and Texture Anisotropy in Dynamically Loaded Tin: Veronica Anghel1; Carl Trujillo1; Ramon Martinez1; George Gray III1; 1Los Alamos National Laboratory
Past materials research efforts have focused on developing constitutive laws and numerical solvers for representing material behavior, but less attention has been paid to the representation of material microstructure. The mechanisms of deformation and damage are strongly dependent on material microstructure. We investigate the plastic behavior and texture anisotropy in tin under dynamic loading over a range of strains. A set of tin Taylor cylinders tested to different strains is studied. The microstructural changes along the Taylor cylinders depend on the strain imposed. Detailed Electron Backscatter Diffraction analysis allow us to understand better the texture evolution with dynamic strain in tin and helps improve models that capture the physics of high-rate material response during highly dynamic events. Statistical distributions of microstructurally relevant features in tin will be discussed in relation to the localization of plastic deformation and damage nucleation and evolution, with focus on grain boundaries and crystallographic orientations.
2:40 PM
Effect of Misorientation Development Near Grain and Twin Boundaries in Pure Copper and Copper-aluminium Alloy: Sandhya Verma1; Prita Pant1; M P Gururajan1; 1Indian Institute of Technology Bombay
Bulk deformation of polycrystalline materials show limitations imposed by the boundary due to requirements of compatibility across boundaries. Here, pure copper (Cu) having coarser twins and copper-8 wt.%-aluminium (Cu8Al) having finer twins are deformed to various strains and then misorientation and orientation gradient development near grain boundaries and twin boundaries is studied. The microstructure is procured using electron backscattered diffraction (EBSD) where misorientation development is explained by kernel average misorientation (KAM). We have shown the variation of misorientation development with boundaries. Misorientation development is also influenced by presence of nearby boundaries and triple junction. We have observed for Cu and Cu8Al that KAM values near boundaries does not behave monotonically. For Cu, it increases as well as decreases in values in one case, while in other case, it remains constant and for Cu8Al it reduces in values for most of cases and increases or remains constant sometimes with strain.
3:00 PM
Rapid Irradiation and Characterization of HT9: Gabriella Bruno1; Kevin Field1; Li He2; T.M. Kelsy Green1; Todd Allen1; 1University of Michigan; 2University of Wisconsin-Madison
Advanced nuclear reactor designs call for unprecedently high damage levels when compared to traditional reactors. Simulating the expected damage can be done with ion irradiations, which achieves damage levels greater than reactors while also capturing the physics of the radiation damage processes. Here, we demonstrate this methodology using HT9, a 12 wt.% chromium, ferritic-martensitic steel. Dual-ion (Fe3+ & He2+) irradiations were controlled to 445+/-15°C, 460+/-15°C, 570+/-15°C at a damage level of 26 dpa and 4 appm He/dpa with an estimated He production of 0.22 appm He/dpa. STEM imaging and composition mapping were used. The cavity number density peaks around 460°C. Dislocation loops decreased in number density and increased in size with increasing temperature. Segregation to the grain boundaries are evident below 460°C and decreases at temperatures above 460°C. Overall, we will show how the present trends based on ion irradiation temperature replicate the expected behavior during fast reactor service.
3:20 PM
The Influence of Alloying in Stabilizing a Faceted Grain Boundary Structure: Jonathan Priedeman1; Gregory Thompson1; 1University of Alabama
Grain boundary structures have long been known to depend on factors such as solutes and temperature. In this work, in-situ atomic scale imaging was used to observe the faceting of a Σ21a [1 1 1]-tilt-axis boundary at 600 and 800 degrees Celsius in a Pt-5Au (at. %) nanocrystalline alloy. With an increase in temperature, we observe an evolution from many, shorter facets to fewer, longer facets. The preferred facets are shown to be symmetrically equivalent tilt boundaries, via the fundamental zone formalism. Simulation of Pt bicrystals reveals that these preferred facets do not lie in an energy minimum (of the tilt boundaries that the grain boundary misorientation could access); however, calculation of the segregation enthalpy of Au to these grain boundary lattice sites indicates a greater preference of Au, reducing the grain boundary energy, and explaining the facet stabilization observed.
3:40 PM
Crystal Mosaicity and Local Alloy Chemistry of Low Angle Grain Boundaries in Ni-based Superalloys: Felicitas Scholz1; Junyang He2; Oliver Horst1; Pascal Thome1; Gunther Eggeler1; Baptiste Gault2; Jan Frenzel1; 1Ruhr-Universitat Bochum; 2Max-Planck-Institut für Eisenforschung GmbH
We report on the formation of crystal mosaicity during seeded single crystal Bridgman solidification and heat treatments of Ni-based superalloys, and its impact on the local alloy composition. In general, single crystals contain low angle misorientation defects referred to as crystal mosaicity. These small sub-grains with misorientations up to a few degrees are inherited from the dendritic growth process. We combine a new tomographic serial sectioning method, cross-correlation based electron back scatter diffraction and atom probe tomography to provide microstructure and local alloy composition analysis. We show that the presence of low angle grain boundaries (LAGBs) between slightly misoriented dendrites is associated with segregation phenomena. For the first time, rhenium segregation is reported for the as-cast and heat-treated states. Rhenium segregate to the dislocation networks building up LAGBs. We discuss our results in light of the present understanding of how rhenium partitions during processing and how it interacts with dislocations.
4:00 PM Cancelled
Insights into the Formation of Al-Cu Intermetallic Compounds during the Solid-liquid Reaction by High-resolution Transmission Electron Microscopy: Jie Chen1; Yongqiong Ren1; Bingge Zhao2; 1Yonggu Group Corporation Co., Ltd.; 2Shanghai University
During Al/Cu solid-liquid reaction, different intermetallic compound (IMCs) are expected, which can affect the mechanical and electrical properties of Al/Cu joints. To tackle this challenge, it is then necessary to tune the interface structure, which requires an insight into the formation mechanism of IMCs. In the current study, Al/Cu liquid-solid reaction was used to fabricate different IMCs. With the aid of focused ion beam (FIB) and high-resolution transmission electron microscopy (HRTEM), the orientation relationship between different IMCs and Cu was identified. Accordingly, the formation mechanism, especially the growth trajectory of Al/Cu IMCs, was addressed. This study provides fundamental understanding on the mechanism behind Al/Cu reaction, which may guide the performance improvement of Al/Cu dissimilar weld.