| Summary: | 碩士 === 義守大學 === 材料科學與工程學系碩士班 === 98 === In this study, Al-12Si alloy repeatedly pressing, hot pressing to change the material conditions of pre-expansion, to understand the impact of the expansion ratio. Through the foaming, the foam material of the hot pressing of pre-foam, the foam parameters and the relationship between magnification. And compression testing, and evaluating different hot pressing conditions, the foaming properties and the nature of the relationship between compression.
After several hot pressing, when the pressing temperature and pressing pressure increases, the expansion ratio will increase. But with the increase in the times of hot pressing, the expansion ratio will graduall decline. Part of the nature of the foam, with the foaming time increased, the foam from the holes in the shape of circular holes into the holes in the polygon, while the internal collapse of the behavior will occur. Compressed nature of the part of the lower foam expansion ratio greater stress should be reduced, but the stress of a short flat area; the expansion ratio and a large foam and vice versa. Compression is mainly by the pore shape and size of the expansion ratio.
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