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  1. Free, publicly-accessible full text available April 1, 2025
  2. Free, publicly-accessible full text available March 1, 2025
  3. Martensitic phase transformation of zirconia (ZrO2), when realized from the superelastic effect, has immense potential in energy applications, such as micro‐actuation and high‐energy dissipation/damping. In this study, martensitic transformation in ZrO2is studied using a newly developed microscale phase field model, which is scale‐independent and contains an averaged gradient term. The model is implemented using the FEniCS package in Python. With a thorough explanation of the model construction, the mechanics of phase transformation are detailed, and the material behaviors under different stress conditions are discussed. Mesh sensitivity, multivariant evolution, and the effect of particle size are analyzed to understand the martensite evolution in superelastic ZrO2. This work provides new insight into the martensitic phase transformation behaviors of micron‐sized spherical ZrO2particles.

     
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  4. Polymer-derived ceramic (PDC) nanocomposites enable access to a large library of functional properties starting from molecular design and incorporating nanofillers. Tailoring preceramic polymer (PCP) chemistry and nanofiller size and morphology can lead to usage of the nanocomposites in complex shapes and coatings with enhanced thermal and mechanical properties. A rational design of targeted nanocomposites requires an understanding of fundamental structure–property–performance relations. Thus, we tailor our discussions of PCP design and nanofiller integration into single source precursors as well as pyrolytic processing for functionalizing PDCs. We also discuss the promises and limitations of advanced characterization techniques such as 4D transmission electron microscopy and pair distribution functions to enable in situ mapping structural evolution. The feedback loop of in situ monitoring sets the foundation for enabling accelerated materials discovery with artificial intelligence. This perspective assesses the recent progress of PDC nanocomposite research nanocomposites and presents scientific and engineering challenges for synthesis, fabrication, processing, and advanced characterization of PDC nanocomposites for enhanced magnetic, electrical, and energy conversion and storage properties. 
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  5. Abstract

    This study focuses on the early stage of polymer‐derived SiOC ceramic conversion. We demonstrate that the perceived SiOC phase separation is nonexistent. Instead, SiO2and free carbon clusters form first and then carbothermal reduction sets in to induce SiOC formation. Such fundamental understanding is supported by both synchrotron X‐ray diffraction study and reactive force field simulation. This work for the first time unifies the understanding of atomic evolution process of polysiloxane‐based polymer to ceramic conversion.

     
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  6. null (Ed.)
    In this study, bulk and porous SiOC materials were synthesized via a polymer-derived ceramic (PDC) method from a base polysiloxane (PSO) precursor and an iron (Fe) catalyst under an inert pyrolytic atmosphere. Fe catalyzes not only the formation and nucleation of β-SiC at lower temperatures but also promotes phase separation of the amorphous SiO x C y phase, compared to PDCs without the Fe catalyst. Samples with Fe pyrolyzed at 1100 °C have an appreciable β-SiC content compared to a negligible/unobservable β-SiC content in the corresponding Fe-less samples. Selective etching of the SiO 2 phase shows that Fe also induces segregation of the amorphous SiO x C y phase, yielding larger specific surface areas and gas sorption capability below 1300 °C. At 1500 °C, the pore structure changes to form interconnected networks due to the highly phase separated SiO 2 and β-SiC microstructure. A Gibbs free energy minimization method was used to determine the relative phase content of the pyrolyzed samples, with the effect of Fe quantified with simplified vapor–liquid–solid (VLS), solid–liquid–solid (SLS), and classical nucleation theories. 
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