Self-organizing Nano-architectured Materials: Pattern Formation and Synthesis
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 8:30 AM
February 28, 2022
Room: 260C
Location: Anaheim Convention Center
Session Chair: Karen Chen-Wiegart, Stony Brook University / Brookhaven National Laboratory; Jonah Erlebacher, Johns Hopkins University
8:30 AM Invited
Self-organizing Gradient Nanostructures via Chemical Heterogeneities: Brad Boyce1; Khalid Hattar1; Remi Dingrevillie1; Doug Medlin1; Joseph Monti1; Alejandro Barrios1; James Nathaniel1; Zachary Milne1; David Adams1; 1Sandia National Laboratories
Gradient nanostructured metals possess unique combinations of properties achieved as a result of the heterogeneous grain structure. However, most efforts to produce gradient nanostructures have relied on differential severe plastic deformation confined to the near-surface regions, such as via surface mechanical attrition treatment or SMAT. Those techniques require line-of-sight access to the surface of interest, and can only produce the finest grain sizes at the surface. In contrast, by depositing a binary nanocrystalline alloy with gradient composition, it is possible to achieve self-stabilized gradient grain sizes through annealing. In this work, we employ phase field calculations to understand the thermodynamic and kinetic effects of the gradient composition and guide the selection of appropriate thermochemical parameters and validate this approach through annealing experiments and Chemi-STEM aberration corrected energy dispersive spectroscopy in the Pt-Au binary alloy system. This new compositional gradient approach offers a new potential for commercial processing of heterogeneous nanostructures.
9:00 AM Invited
Hierarchical Morphologies in Co-sputter Deposited Thin Films: Amit Misra1; 1University of Michigan
Self-organization during growth of elevated temperature sputter co-deposition of alloy thin films with immiscible elements could lead to monomodal or hierarchical phase-separated morphologies. Using transmission electron microscopy characterization of a series of immiscible alloy systems, (Cu-Mo, Cu-Ag, Cu-Fe, Cu-Ta, Mo-Ag, Cu-Mo-Ag), and phase-field modeling, indicate that hierarchical structures form with sufficient disparity in kinetic energy between the constituent atoms, one species being highly mobile (A) and the other relatively immobile (B). Typically, reduced deposition rate and large difference in homologous temperatures of the depositing elements tends to favor the formation of hierarchical morphology comprised of multiple phase-separated microstructure morphologies from nanometer to sub-micrometer scales. The observations are interpreted via a model incorporating material properties and process parameters. Thin films with hierarchical morphologies exhibit high flow strengths that are comparable to monomodal nanoscale morphology but significantly higher strain hardening rate, higher plastic deformability and higher fracture resistance.
9:20 AM
Microporous Nanoparticle Emulsion Thermosets for Multi-material, Multifunctional Porous Nano-composites: Yogin Patel1; Michael Grzenda1; Charm Nicholas1; Molla Hasan2; Jonathan Singer1; 1Rutgers–New Brunswick; 2Alfred University
We have developed microporous nanoparticle emulsion thermosets (MiNET), a new class of nano-composites made from epoxies and nanoparticles, a liquid porogen, and a small quantity of surfactant. These ingredients form an intermediate between a conventional surfactant a Pickering emulsion to create a bicontinuous network of oil and epoxy composite throughout the processing. After a room temperature cure and usage of different functional nanoparticles, based on the performance requirements of a given application, it is possible to design a composite with a range of functionality like flexibility, inertness, and conductivity. Further extraction of the oil phase through rinsing, MiNETs can be converted into porous (30~60% open volume) structures without considerable volume shrinkage (~1~5%). The pore size (between 100~10,000 nm) and chemical functionality of the nanopores is tunable by the constituent nanoparticles. These novel thermosets molded into various complex forms. For example, we have demonstrated parallel-processed electrospray emitters at micrometer scale.
9:40 AM Break
10:00 AM Invited
Nanoporous Nanoparticles: From Catalysis to 3D Printing: Jonah Erlebacher1; Alyssa Chuang1; Pheobe Appel1; Jodie Baris1; 1Johns Hopkins University
Dealloying provides a particularly facile route to the synthesis of high surface area nanoporous nanoparticles, i.e., particles with mesoscopic geometric diameter that themselves contain porosity with a ligament size an order of magnitude smaller. In our laboratory, we have developed a number of routes to make these materials include nanoporous Pt nanoparticles with ~3 nm pores inside 15 nm particles, and nanoporous Ta particles 10 microns in diameter possessing 100 nm pores. In this talk, we will discuss methods for the next level assembly of such particles into more complex architectures. We are addressing this problem by studying useful and novel dealloying systems guided by insights from kinetic Monte Carlo modeling. The central question is this: how can we organize these particles using the traditional levers of thermal and mechanical treatments (e.g., sintering or 3D printing), without destroying the functional porosity within the particles.
10:30 AM Invited
Grain Boundary Formation through Particle Detachment during Coarsening of Nanoporous Metals: Kate Elder1; W. Beck Andrews2; Markus Ziehmer3; Alexander Chadwick1; Erica Lilleodden3; Katsuyo Thornton2; Peter Voorhees1; 1Northwestern University; 2University of Michigan; 3Helmholtz-Zentrum Geesthach
Grain boundary formation during coarsening of nanoporous gold (NPG) is investigated wherein a nanocrystalline structure can form by particles detaching and reattaching to the structure. Experiments show that an in-grain orientation spread develops as NPG is coarsened. The volume fraction of the NPG sample is near the limit of bicontinuity, at which simulations predict that a bicontinuous structure begins to fragment into independent particles during coarsening. We predict that up to ~5% of the NPG structure detaches during coarsening. The total volume detached is highly dependent on the volume fraction and volume fraction homogeneity of the nanostructure. As the void phase in the experiments cannot support independent particles, they must fall and reattach to the structure, a process that results in the formation of new grain boundaries. This particle reattachment process, along with other classical processes, leads to the formation of grain boundaries during coarsening in nanoporous metals.
11:00 AM
Quasi-periodic Nanoarchitectures in Eutectic Thin Films: Lengthscales and Inherent Instabilities: Eli Sullivan1; Jonathan Skelton1; James Fitz-Gerald1; Jerrold Floro1; 1University of Virginia
Directional melting and solidification in eutectic alloys forms interdigitated bicrystals with regular, irregular or chaotic nanoarchitectures, with lengthscales that are controlled by the solidification speed. Eutectic nanostructures can be obtained in bulk, thin films and particles, and across metals, oxides and polymers. The resultant structure is of interest for studying interfacial scattering and anisotropy in energy transport, and as an alternative schema for nanostructured functional materials. In eutectic Al-Cu thin films, highly-regular, parallel phase lamellae with periodicities below 50 nm are readily obtained, and values below 20 nm should be achievable. Chaotic lamellar structures featuring continuous but tortuous lamellae may occur when composition deviates from the eutectic. Solitary tilt waves, oscillatory instabilities, and extreme lamellar branching events arise due to inherent instabilities associated with the moving solid-liquid interface during hypoeutectic solidification. Additional structural control may be afforded using pre-imposed patterning. Support of the NSF under grant DMR-1663085 is gratefully acknowledged.
11:20 AM
Elucidating the Kinetics for Three-dimensional Bicontinuous Structures Formation
in Molten Salt Dealloying via In Situ Synchrotron X-ray Nano-tomography
: Xiaoyang Liu1; Arthur Ronne1; Kaustubh Bawane2; Xiaoyin Zheng1; Yang Liu1; Lin-Chieh Yu1; Mingyuan Ge3; Phillip Halstenberg4; Xianghui Xiao3; Shannon Mahurin5; Sheng Dai6; Wah-Keat Lee3; James Wishart3; Lingfeng He2; Yu-chen Chen-Wiegart7; 1Stony Brook University; 2Idaho National Laboratory; 3Brookhaven National Laboratory; 4University of Tennessee; 5Oak Ridge National Laboratory; 6University of Tennessee/ Oak Ridge National Laboratory; 7Stony Brook University/ Brookhaven National Laboratory
Three-dimensional (3D) nanoporous metals have been drawing research interests both for intriguing fundamental sciences and for their potential applications in catalysts, sensors, battery and supercapacitor materials. To-date, numerous dealloying methods such as chemical/electrochemical dealloying, liquid metal dealloying, solid-state interfacial dealloying and vapor phase dealloying have been developed to fabricate various porous metals. The present study utilizes the corrosive nature of molten salts to create porous Ni forming from dealloying a Ni-20Cr alloy at 800℃ in molten chloride salts. With in situ synchrotron X-ray nano-tomography studies, the possible rate-determining step was determined to be the long-range diffusion. Further in situ study was conducted at lower temperatures (500 and 600℃) combined with high-resolution transmission electron microscopy characterization to understand the influence of temperature on the chemical dissolution and surface diffusion. This study provides new insights on molten salt dealloying for potential functional materials fabrication.