Browsing by Author "Chen, S"

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    Neutron diffraction residual stress determinations on Intermetallic alloy components produced by wire-arc additive manufacturing (WAAM)
    (Australian Institute of Nuclear Science and Engineering (AINSE), 2018-11-01) Chen, S; Ma, Y; Li, HJ; Mark, R; Paradowska, AM
    Intermetallic alloys such as aluminides of titanium, nickel and iron exhibit an attractive combination of physical and mechanical properties such as high melting point, low density, high strength, good oxidation, and creep resistance, due to their strong internal order and mixed bonding. However, the properties of these materials are often obtained at a cost in terms of ease of manufacturing. In recent years the WAAM process has been successfully applied to in-situ produce TiAl and Fe3Al intermetallic components with designed chemical compositions. One of the major concern is residual stresses (RS) distribution in the WAAM fabricated components as it not only influences the part tolerance but also cause premature failure. The neutron diffraction technique has been recognised as the most precise and reliable method of mapping sub-surface RS in components for both academic and industrial-economic relevance. Considering the outstanding capability of obtaining RS non-destructively deep within the interior of components, our study utilised neutron diffraction technique to conduct RS measurement by the angular scanning instrument KOWARI. Furthermore, an averaging method has been developed for the WAAM multi-bead build up intermetallic alloys with large grain size. With the averaging method applied during experimental setup and data processing, reasonable residual stress results have been obtained from the acquired neutron diffraction data.
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    Novel low-strain layered/rocksalt intergrown cathode for high-energy Li-ion batteries
    (American Chemical Society (ACS), 2023-11-16) Xu, L; Chen, S; Su, Y; Shen, X; He, J; Avdeev, M; Kan, WH; Zhang, B; Fan, W; Chen, L; Cao, D; Lu, Y; Wang, L; Wang, M; Bao, L; Zhang, L; Li, N; Wu, F
    Both layered- and rocksalt-type Li-rich cathode materials are drawing great attention due to their enormous capacity, while the individual phases have their own drawbacks, such as great volume change for the layered phase and low electronic and ionic conductivities for the rocksalt phase. Previously, we have reported the layered/rocksalt intergrown cathodes with nearly zero-strain operation, while the use of precious elements hinders their industrial applications. Herein, low-cost 3d Mn4+ ions are utilized to partially replace the expensive Ru5+ ions, to develop novel ternary Li-rich cathode material Li1+x[RuMnNi]1-xO2. The as-designed Li1.15Ru0.25Mn0.2Ni0.4O2 is revealed to have a layered/rock salt intergrown structure by neutron diffraction and transmission electron microscopy. The as-designed cathode exhibits ultrahigh lithium-ion reversibility, with 0.86 (231.1 mAh g-1) out of a total Li+ inventory of 1.15 (309.1 mAh g-1). The X-ray absorption spectroscopy and resonant inelastic X-ray scattering spectra further demonstrate that the high Li+ storage of the intergrown cathode is enabled by leveraging cationic and anionic redox activities in charge compensation. Surprisingly, in situ X-ray diffraction shows that the intergrown cathode undergoes extremely low-strain structural evolution during the charge-discharge process. Finally, the Mn content in the intergrown cathodes is found to be tunable, providing new insights into the design of advanced cathode materials for high-energy Li-ion batteries. © 2024 American Chemical Society.