Al-Mg-Si계 주조용 합금의 주조성 및 기계적 특성에 미치는 Fe, Mn 함량의 영향

Abstract

Eeffects of iron and manganese contents on castability and mechanical properties have been studied in Al-4Mg-0.9Si casting alloys. Fraction of α compounds increased as Mn content increased and fraction of β compounds increased as Fe content increased. Crystallization temperatures of α-Al5(Fe,Mn)3Si2 and β-Al5FeSi compounds were elevated and higher than that of eutectic Mg2Si, by 20℃. Castability was affected α and β compounds. Fluidity decreased as Fe and Mn contents increased in Al-4Mg-0.9Si melts. Micro-shrinkage increased as Fe and Mn contents increased but macro-shrinkage decreased as Fe and Mn contents increased in Al-4Mg-0.9Si melts. As Fe content in Al-4Mg-0.9Si-0.3Mn melts increased from 0.1wt.% to 0.4wt.%, tensile strength decreased about 4.2% and elongation remarkably decreased by 22.5%. As Mn content in Al-4Mg-0.9Si-0.3Fe melts increased from 0.3wt.% to 0.5wt.%, however, tensile strength increased by 7%, but elongation was nearly same.