Effects of Sc content on the microstructure of As-Cast Al-7 wt.% Si alloys

Journal Article · Sun Apr 15 04:00:00 EDT 2012 · Materials Characterization

DOI:https://doi.org/10.1016/J.MATCHAR.2011.11.005· OSTI ID:22066442

Jing, Yang; Jinzhi, Dang; Hong, Xu ^[1]; Zhenmin, Du ^[2]

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1. School of Materials Science and Engineering, North University of China, Taiyuan 030051 (China)
2. School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China)

The effects of Sc content on the microstructure of as-cast Al-Si alloys were investigated by adding 0.05, 0.1, 0.15, 0.2, 0.25, 0.3, and 0.4 wt.% Sc to hypoeutectic Al-7 wt.% Si alloys. The results show that there are significant changes in the microstructure when the Sc content is increased to 0.15%. The volume fraction of the primary {alpha}-Al phase increased nearly monotonically with increasing Sc content in the as-cast state. As the Sc content increased, the average length of the eutectic Si in the as-cast Al-7Si-xSc alloy decreased sharply from 150 {mu}m (without Sc content) to 20 {mu}m (0.4 wt.% Sc content). The Sc atoms are concentrated in the interdendritic regions. A fish-bone structure composed of Al, Si, Sc, and Fe, which might be the Fe-rich phase precipitated on the AlSc{sub 2}Si{sub 2} (V-phase) was detected adjacent to the grain boundary by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). - Highlights: Black-Right-Pointing-Pointer Significant changes in the microstructure when the Sc content is increased to 0.15%. Black-Right-Pointing-Pointer Volume fraction of the primary a-Al phase increased with increasing Sc content. Black-Right-Pointing-Pointer Average length of Si decreased sharply from 150 to 20 {mu}m with increasing Sc content. Black-Right-Pointing-Pointer The Sc atoms are concentrated in the interdendritic regions.

• OSTI ID: 22066442
• Journal Information: Materials Characterization, Journal Name: Materials Characterization Journal Issue: Complete Vol. 66; ISSN 1044-5803; ISSN MACHEX
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM BASE ALLOYS
CONCENTRATION RATIO
EUTECTICS
GRAIN BOUNDARIES
GRAIN REFINEMENT
LENGTH
MODIFICATIONS
SCANDIUM ADDITIONS
SCANNING ELECTRON MICROSCOPY
SILICON ALLOYS
X-RAY SPECTROSCOPY