| Summary: | 碩士 === 國立臺灣科技大學 === 機械工程系 === 104 === In this study, the cast AZ31 and AZ61 magnesium alloys were processed by equal channel angular pressing (ECAP) and were comminuted into chips by filing with a rasp to measure the properties of hydrogen storage. Effects of processing pass and route of ECAP on AZ series magnesium alloys hydrogen storage properties were investigated. In addition to studying the effects of ECAP on hydrogen storage properties, we also investigated the effects of additives on hydrogen storage properties by adding activated carbon (AC) and nickel powder (Nip). Different from high energy ball milling technique, the catalysts were added and mixed by gravity cast with mechanical stirring to prepare Mg-based composite materials for hydrogen storage. The materials were further comminuted into chips by filing with a rasp to measure the hydrogen storage properties of AZ metal matrix composites (MMCs). The absorption and desorption of hydrogen were measured by Sievert-type hydrogen measurement system in this research.
These results indicated that after the ECAP processing, the AZ alloys lead to severe dynamic recrystallization and achieved grain refinement. AZ31 processed by ECAP route BC with 8 passes provided the best result of the grain refinement, and elevated the absorption and desorption rate of hydrogen, exhibited high gravimetric hydrogen storage capacity of 7 wt.%. Furthermore, compared to the AZ alloys without any additives, AZ31-5C and AZ31-5C-0.5Ni significantly increased the absorption and desorption rate of hydrogen and the hydrogen storage capacity were 6.9 wt.% and 6.3 wt.%, respectively.
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