The development of high-fidelity mechanical property prediction models for the design of polycrystalline materials relies on large volumes of microstructural feature data. Concurrently, at these same scales, the deformation fields that develop during mechanical loading can be highly heterogeneous. Spatially correlated measurements of 3D microstructure and the ensuing deformation fields at the micro-scale would provide highly valuable insight into the relationship between microstructure and macroscopic mechanical response.
View Article and Find Full Text PDFTwo-phase nanolaminates are known for their high strength, yet they suffer from loss of ductility. Here, we show that broadening heterophase interfaces into "3D interfaces" as thick as the individual layers breaks this strength-ductility trade-off. In this work, we use micropillar compression and transmission electron microscopy to examine the processes underlying this breakthrough mechanical performance.
View Article and Find Full Text PDFThe abrupt occurrence of twinning when Mg is deformed leads to a highly anisotropic response, making it too unreliable for structural use and too unpredictable for observation. Here, we describe an in-situ transmission electron microscopy experiment on Mg crystals with strategically designed geometries for visualization of a long-proposed but unverified twinning mechanism. Combining with atomistic simulations and topological analysis, we conclude that twin nucleation occurs through a pure-shuffle mechanism that requires prismatic-basal transformations.
View Article and Find Full Text PDFTungsten displays high strength in extreme temperature and radiation environments and is considered a promising plasma facing material for fusion nuclear reactors. Unlike other metals, it experiences substantial irradiation hardening, which limits service life and presents safety concerns. The origin of ultrahigh-irradiation hardening in tungsten cannot be well-explained by conventional strengthening theories.
View Article and Find Full Text PDFHigh-throughput atomistic simulations reveal the unique effect of solute atoms on twin variant selection in Mg-Al alloys. Twin embryo growth first undergoes a stochastic incubation stage when embryos choose which twin variant to adopt, and then a deterministic growth stage when embryos expand without changing the selected twin variant. An increase in Al composition promotes the stochastic incubation behavior on the atomic level due to nucleation and pinning of interfacial disconnections.
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