Self-organizing Nano-architectured Materials: Poster Session
Program Organizers: Yu-chen Karen Chen-Wiegart, Stony Brook University / Brookhaven National Laboratory; Ian Mccue, Northwestern University; Erica Lilleodden, Fraunhofer Insitute for Microstructure of Materials and Systems (IMWS); Pierre-Antoine Geslin, CNRS / INSA-Lyon; Qing Chen, Hong Kong University of Science & Technology

Monday 5:30 PM
February 28, 2022
Room: Exhibit Hall C
Location: Anaheim Convention Center

Session Chair: Yu-chen Karen Chen-Wiegart, Stony Brook University / Brookhaven National Laboratory; Ian McCue, Northwestern University; Erica Lilleodden, Helmholtz-Zentrum hereon; Pierre-Antoine Geslin, CNRS / INSA-Lyon; Qing Chen, Hong Kong University of Science & Technology


H-14: Characterization of Dealloyed Gradient Nanoporous Foams: Karina Hemmendinger1; Andrea Hodge1; 1University of Southern California
     Nanoporous metal foams possess an interesting combination of properties including good electrical and thermal conductivity, surface-to-volume ratio and yield strength. Individual properties can be tuned through changes in the foam morphology, including ligament and pore size. Dealloying, a selective corrosion process, is a versatile synthesis method for nanoporous materials as it is compatible with a wide range of alloy compositions and electrolytic solutions, and is capable of producing a wide range of pore sizes. Gradient nanoporous metal foams present an opportunity for novel combinations of chemical and mechanical properties, although further study is needed to establish the stability and properties of the microstructure at the interface. A variety of techniques such as SEM, TEM and nanoindentation will be used to characterize the foam morphology, microstructure, and mechanical behavior of these materials.

H-15: In-situ Observation of Ligament Coarsening in Nanoporous Gold: Kerry Baker1; T Balk1; 1University of Kentucky
    Nanoporous gold has a high surface area to volume structure that, combined with its material properties, makes it attractive for catalytic, sensing, and capacitance applications. The size of the ligament structure influences the mechanical behavior of nanoporous gold, as an increase in ligament size decreases the strength of the networked structure. Typically, a smaller ligament size is preferred due to the high surface area to volume ratio and enhanced mechanical properties; however, the structure is not thermally stabilized at elevated temperatures. Thin film nanoporous gold films were coarsened in a scanning electron microscope, with in-situ observations during the annealing process. It was found that ligament coarsening kinetics agreed with a surface diffusion mechanism, as expected. However, electron beam imaging was observed to influence the coarsening behavior significantly. These findings will be discussed in relation to electron beam effects on gold ligament surfaces and diffusion.

H-16: Kinetics of Peritectic Melting: Mingwang Zhong1; Longhai Lai1; Alain Karma1; 1Northeastern University
    Recent experiments and a phase-field modeling study presented in another talk in this symposium have demonstrated that melting of a peritectic alloy can produce bicontinuous structures of two interpenetrating phases analogous to those obtained by other dealloying methods. This talk will present the results of additional phase-field simulations that further explore the kinetics of this process in the Ti-Ag alloy system that, at the peritectic temperature, exhibits a Ag-rich liquid at equilibrium with a Ti-rich solid α phase and a Ti50Ag50 solid β phase. The melting kinetics of the β phase is studied as a function of temperature and material parameters. The results reveal that depending on the superheating above the peritectic temperature and the excess free-energies of the solid-solid and solid-liquid interfaces, melting can occur by two distinct mechanisms that include the known mechanism of liquid film migration and a novel mechanism of liquid channel growth.

H-19: Unveiling Phase Transition in Solid-state Dealloyed Thin Films Using Autonomous Synchrotron X-ray Characterization: Cheng-Chu Chung1; Chonghang Zhao1; Marcus Noack2; Kedar Manandhar3; Joshua Lynch4; Hui Zhong1; Ming Lu4; Mingzhao Liu4; Jianming Bai4; Philip Maffettone4; Daniel Olds4; Masafumi Fukuto4; Ichiro Takeuchi3; Sanjit Ghose4; Thomas Caswell4; Kevin Yager4; Yu-Chen Chen-Wiegart1; 1Stony Brook University; 2Lawrence Berkeley National Laboratory; 3University of Maryland; 4Brookhaven National Laboratory
    Thin-film solid-state interfacial dealloying (SSID) recently emerged as an attractive method for forming bi-continuous metal-metal composites and nano-porous metal films. This offers the potential to create nano-architectured materials with a broader range of elemental composition, at a lower processing temperature compared with the liquid metal dealloying. However, the processing-structure relationship in thin-film SSID remains unclear due to the limitations of a large parameter space, such as the parting limit, thin-film thickness, dealloying time, and temperature. In this work, we applied machine learning-augmented methods to analyze the phase compositions resulting from these parameters. Through synchrotron X-ray diffraction (XRD) where the conventional grid scanning, Gaussian process (gpCAM), crystallography companion agent (XCA) methods were tested, we explored the three-dimensional parameter space of potential dealloying systems. Such an autonomous experimental approach can be further combined with other machine learning-driven methods for materials design, providing valuable insights into the thin-film SSID process.