DÖKÜM Al-10Mg2Si İN-SİTÜ KOMPOZİTLERİN KOROZYON

Abstract

The hypoeutectic Al-10Mg2Si (wt%) composites, also denoted as Al-6.3Mg-3.7Si (wt%) alloy, were cast in a steel step mould, in which different solidification rates were obtained. The microstructural characterizations were made by optical microscope and XRD. Corrosion performances were measured by immersion and electrochemical corrosion tests in 3.5% NaCl solution. Microstructure analysis showed that all the alloys consisted of -Al, Chinese script type Mg2Si and needle-like Al5FeSi phases. Increasing solidification rate resulted in a remarkable refinement of Chinese script-like eutectic Mg2Si phases. Corrosion tests revealed that increasing solidification rate improved the corrosion resistance of Al-10Mg2Si composites due to the more uniform distribution of Mg2Si phases and the stabilization of protective oxide films on the sample surface.