Publications
Prof. Zonghoon Lee’s Atomic-Scale Electron Microscopy Lab
Prof. Zonghoon Lee’s Atomic-Scale Electron Microscopy Lab
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Publications in Nature | Science | their sister journals
Nature, 629, 348-354,2024 / Nature Communications, 14:4747, 2023 / Nature Communications, 13:4916, 2022 / Nature Communications, 13:2759, 2022 / Nature, 596, 519-524, 2021 / Nature, 582, 511-514, 2020 / Nature Nanotechnology, 15, 289-295, 2020 / Nature Nanotechnology, 15, 59-66, 2020 / Science Advances, 6 (10), eaay4958, 2020 / Nature Electronics, 3, 207-215, 2020 / Nature Communications, 11 (1437), 2020 / Nature Energy, 3, 773-782, 2018 / Nature Communications, 8:1549, 2017 / Nature Communications, 6:8294, 2015 / Nature Communications, 6:7817, 2015 / Nature Communications, 5:3383, 2014
Abstract
The microstructural evolution during processing and tensile deformation of a nanocrystalline Al-Ti-Cu alloy was investigated using transmission and scanning electron microscopy. Grain refinement was achieved by cryomilling of elemental powders, and powders were consolidated by hot isostatic pressing (“HIPing”) followed by extrusion to produce bulk nanocrystalline Al-Ti-Cu alloys. In an effort to enhance ductility and toughness of nanocrystalline metals, multiscale structures were produced that consisted of nanocrystalline grains and elongated coarse-grain (CG) bands of pure aluminum. Examination of bulk tensile fracture samples revealed unusual failure mechanisms and interactions between the CG bands and nanocrystalline regions. The ductile CG bands underwent extensive plastic deformation prior to fracture, while nanocrystalline regions exhibited nucleation and growth of voids and microcracks. Cracks tended to propagate from nanocrystalline regions to the CG bands, where they were effectively arrested by a combination of crack blunting and crack bridging. These processes were instrumental in enhancing the toughness and ductility of the nanocrystalline alloy.