| Title |
A Study on Microstructure Formation during Directional Solidification of a Hypoeutectic Al-11.3Si-3.5Cu alloy |
| Authors |
서희식(Hee Sik Seo); 구지호(Ji Ho Gu); 박경미(Kyung Mi Park); 이정석(Jeong Seok Lee); 이재현(Je Hyun Lee); 정원섭(Won Sub Chung) |
| DOI |
https://doi.org/10.3365/KJMM.2012.50.12.897 |
| ISSN |
1738-8228(ISSN), 2288-8241(eISSN) |
| Keywords |
Al-Si alloy; directional solidification; solidification rate; segregation; dendrite spacing |
| Abstract |
Directional solidification experiments were carried out in a hypoeutectic Al-11.3Si-3.5Cu system to investigate the microstructural evolution with the solidification rate. At a fixed temperature gradient, a dendritic microstructure was observed at a constant speed of more than 25 ㎛s-1, a cellular interface developed at 5 ㎛s-1 and the growth rate of 0.5 ㎛s-1 led to the stability of the planar interface. The results revealed that primary silicon phases formed among cells, even though the studied Al-Si alloy system formed the composition within a hypoeutectic silicon composition. This suggests that the liquid concentration among cells during solidification reached a higher concentration, i.e., the eutectic concentration. It is, however, interesting that primary silicon phases did not form during a dendritic growth of more than 25 ㎛s-1. These experimental observations are explained using the theoretical models on the interface temperatures. |