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Vol.55, No.6, 386 ~ 396, 2017
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| Title |
| Microstructure and High Temperature Plastic Deformation Behavior of Al-12Si Based Alloy Fabricated by an Electromagnetic Casting and Stirring Process |
| 전경수 Kyung-soo Jeon , 노흥렬 Heung-ryeol Roh , 김목순 Mok-soon Kim , 김종호 Jong-ho Kim , 박준표 Joon-pyo Park |
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| Abstract |
| An as-received EMC/S (electromagnetic casting and stirring)-processed Al-12Si based alloy billet was homogenized to examine its microstructure and high temperature plastic deformation behavior, using compressive tests over the temperature range from 623 to 743 K and a strain rate range from 1.0×10-3 to 1.0×100s-1. The results were compared with samples processed by the direct chill casting (DC) method. The fraction of equiaxed structure for the as-received EMC/S billet(41%) was much higher than that of the as-received DC billet(6%). All true stress - true strain curves acquired from the compressive tests exhibited a peak stress at the initial stage of plastic deformation. Flow stress showed a steady state region after the appearance of peak stress with increasing strain. The peak stress decreased with increasing temperature at a given strain rate and a decreasing strain rate at a given temperature. A constitutive equation was made for each alloy, which could be used to predict the peak stress. A recrystallized grain structure was observed in all the deformed specimens, indicating that dynamic recrystallization is the predominant mechanism during high temperature plastic deformation of both the homogenized EMC/S and DC-processed Al-12Si based alloys.
(Received September 28, 2016; Accepted December 9, 2016) |
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| Key Words |
| Al alloy, deformation, compression test, transmission electron microscopy (TEM), recrystallization |
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