전자기주조법으로 제조된 Al-12Si계 합금의 미세조직 및 고온 소성변형 거동 |
전경수1, 노흥렬1, 김목순1, 김종호2, 박준표2 |
1인하대학교 신소재공학과 2포항산업과학연구원 금속소재연구그룹 |
Microstructure and High Temperature Plastic Deformation Behavior of Al-12Si Based Alloy Fabricated by an Electromagnetic Casting and Stirring Process |
Kyung-Soo Jeon1, Heung-Ryeol Roh1, Mok-Soon Kim1, Jong-Ho Kim2, Joon-Pyo Park2 |
1Division of Materials Science and Engineering, Inha University, Incheon 22212, Republic of Korea 2Avanced Metallic Materials Research Group, Research Institute of Industrial Science & Technology, Pohang 37655, Republic of Korea |
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Received: 28 September 2016; Accepted: 9 December 2016. Published online: 1 June 2017. |
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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. |
Keywords:
Al alloy, deformation, compression test, transmission electron microscopy (TEM), recrystallization |
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