Summary: | 碩士 === 國立高雄第一科技大學 === 機械與自動化工程所 === 94 === Abstract
The Magnesium alloys are considered as the alternative materials of the plastics
for thecate of 3C products due to their properties such as low density, high strength to
density to ratio, able to be recycled, high thermal conductivity etc.. At present, the
manufacturing of the case is almost conducted by die casting process. However, the
metal forming process such as stamping and forging is considered as the best method
instead of the die casting process and is used in researched of various types of
magnesium gradually. The percentage of market share will be expected to become
larger and larger at the same time. Not only casting but also metal forming, the amount
of scrap are tremendous, which will result in the problems of environment. Therefore,
the way to recycle the scraps is worth researching.
The recycling process in solid state of the AZ31B magnesium scraps from
stamping process is investigated in this study by using the hybrid process of hot
pressing and extrusion. In addition, the information relative to the recycling process of
the AZ31B magnesium scraps from stamping process is expected to be built up and is
provided to the industry as reference during mass production. As the scrap particles of
1mm3 , 125mm3 and 1000mm3 are prepared as the prepared to investigate the
solid-state recycled process, the results show that the optimum process variables such as
1000mm3 for the particle size of scrap, and 300℃for hot pressing will be obtained with
247MPa in tensile strength, 150MPa in yield strength and 20% in Elongation, which
conform to the requirements of specification. The mechanical properties of the recycled
materials hot-pressed in vacuum are better than those of hot-pressed in air.
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