| Title |
Microstructure and High Temperature Plastic Deformation Behavior of Al-12Si Based Alloy Fabricated by an Electromagnetic Casting and Stirring Process |
| Authors |
전경수(Kyung-soo Jeon); 노흥렬(Heung-ryeol Roh); 김목순(Mok-soon Kim); 김종호(Jong-ho Kim); 박준표(Joon-pyo Park) |
| DOI |
https://doi.org/10.3365/KJMM.2017.55.6.386 |
| ISSN |
1738-8228(ISSN), 2288-8241(eISSN) |
| Keywords |
Al alloy; deformation; compression test; transmission electron microscopy (TEM); recrystallization |
| 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) |