Dehydrogenation and Sintering of TiH2: An In Situ Study
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This first-ever study investigated dehydrogenation and microstructural evolution of TiH2 during sintering under vacuum using in situ neutron diffraction, in situ transmission electron microscopy, and ex situ neutron tomography. The densification behavior, microstructure, hydrogen concentration, and in situ phase transformation were reported. The shrinkage, weight loss percentage, and densification of the TiH2 powder compact monotonically increase with sintering temperature, while the open porosity behaves differently; porosity first increases at the initial sintering stage and then decreases during further sintering. The in situ phase transformation observations reveal that dehydrogenation starts from the outer area of either a particle or a powder compact and progressively carries forward into the interior of the particle or the compact. A shrinking core model was proposed to elucidate the dehydrogenation process for a single particle and a powder compact.
KeywordsDehydrogenation Neutron Diffraction Titanium Hydride Shrink Core Model Neutron Tomography
We would like to thank the financial support from the Ministry of Business Innovation and Employment (MBIE), New Zealand. We acknowledge the support of the Bragg Institute, Australian Nuclear Science and Technology Organisation (ANSTO), in providing the neutron research facilities used in this work. The authors also wish to thank the Australian Institute of Nuclear Science and Engineering (AINSE) Ltd. for providing financial assistance (award No. P3430) to us for conducting work on WOMBAT and DINGO. The University of Queensland is acknowledged for providing the access to the Tecnai F20 TEM facility. GC also appreciates the funding from Shaanxi Youth Science and Technology New Star Project (No.: 2016KJXX-78), and Shaanxi Science and Technology Co-ordination and Innovation Project (No.: 2016KTCQ01-113). This work is also supported by State Key Laboratory for Powder Metallurgy, Central South University, Changsha, P.R. China.
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