A Study on the High-Strain-Rate Superplasticity and Injection Molding of Zn-22 % Al Alloys Produced by Reciprocating Extrusion
碩士 === 國立清華大學 === 材料科學工程學系 === 87 === Reciprocating extrusion was applied to processed super-plastic Zn-22 % Al alloys. In order to discuss the effect of extrusion times on microstructure and grain size, reciprocating processes were performed on the billets with 1, 5 and 10 times at 200℃, respective...
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ndltd-TW-087NTHU01590782016-07-11T04:13:20Z http://ndltd.ncl.edu.tw/handle/09229367437928304329 A Study on the High-Strain-Rate Superplasticity and Injection Molding of Zn-22 % Al Alloys Produced by Reciprocating Extrusion 往復式擠製Zn-22%Al合金高速超塑性及射出成型性之研究 Y. C. Huang 黃元璋 碩士 國立清華大學 材料科學工程學系 87 Reciprocating extrusion was applied to processed super-plastic Zn-22 % Al alloys. In order to discuss the effect of extrusion times on microstructure and grain size, reciprocating processes were performed on the billets with 1, 5 and 10 times at 200℃, respectively. Increasing extrusion times can refine the grain of alloys to 0.3 m and obtain high angle grain structure. Furthermore, increasing extrusion times can effectively promote superplastic elongation. The optimum superplastic condition is the extrusion at 200℃ for 10 times combining with testing at 200℃ and strain rate at 2×10-2 s-1. The elongation can attain to 2510%, is almost the same with the best result in the memorials. Secondly, the high temperature fracture surfaces at low m values are dimple structure, and those at high m values are grain boundary sliding structure. It reveals that the behavior of grain boundary sliding is more active at high m values. In addition, the component of strain induced grain growth at high strain rate is more than that at low strain rate. At last, the injection molding processes were performed at 8×10-2 s-1 to form a disk with two raised ring. There were no cracks in these products. The results reveal that the Zn-22 % Al alloys pro-duced by reciprocating extrusion have the ability of near net shape forming. J. W. Yeh 葉均蔚 1999 學位論文 ; thesis 128 zh-TW |
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碩士 === 國立清華大學 === 材料科學工程學系 === 87 === Reciprocating extrusion was applied to processed super-plastic Zn-22 % Al alloys. In order to discuss the effect of extrusion times on microstructure and grain size, reciprocating processes were performed on the billets with 1, 5 and 10 times at 200℃, respectively.
Increasing extrusion times can refine the grain of alloys to 0.3 m and obtain high angle grain structure. Furthermore, increasing extrusion times can effectively promote superplastic elongation. The optimum superplastic condition is the extrusion at 200℃ for 10 times combining with testing at 200℃ and strain rate at 2×10-2 s-1. The elongation can attain to 2510%, is almost the same with the best result in the memorials. Secondly, the high temperature fracture surfaces at low m values are dimple structure, and those at high m values are grain boundary sliding structure. It reveals that the behavior of grain boundary sliding is more active at high m values. In addition, the component of strain induced grain growth at high strain rate is more than that at low strain rate. At last, the injection molding processes were performed at 8×10-2 s-1 to form a disk with two raised ring. There were no cracks in these products. The results reveal that the Zn-22 % Al alloys pro-duced by reciprocating extrusion have the ability of near net shape forming.
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author2 |
J. W. Yeh |
author_facet |
J. W. Yeh Y. C. Huang 黃元璋 |
author |
Y. C. Huang 黃元璋 |
spellingShingle |
Y. C. Huang 黃元璋 A Study on the High-Strain-Rate Superplasticity and Injection Molding of Zn-22 % Al Alloys Produced by Reciprocating Extrusion |
author_sort |
Y. C. Huang |
title |
A Study on the High-Strain-Rate Superplasticity and Injection Molding of Zn-22 % Al Alloys Produced by Reciprocating Extrusion |
title_short |
A Study on the High-Strain-Rate Superplasticity and Injection Molding of Zn-22 % Al Alloys Produced by Reciprocating Extrusion |
title_full |
A Study on the High-Strain-Rate Superplasticity and Injection Molding of Zn-22 % Al Alloys Produced by Reciprocating Extrusion |
title_fullStr |
A Study on the High-Strain-Rate Superplasticity and Injection Molding of Zn-22 % Al Alloys Produced by Reciprocating Extrusion |
title_full_unstemmed |
A Study on the High-Strain-Rate Superplasticity and Injection Molding of Zn-22 % Al Alloys Produced by Reciprocating Extrusion |
title_sort |
study on the high-strain-rate superplasticity and injection molding of zn-22 % al alloys produced by reciprocating extrusion |
publishDate |
1999 |
url |
http://ndltd.ncl.edu.tw/handle/09229367437928304329 |
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