Microstructures and corrosion resistance of as‐cast aluminum‐10 wt.% silicon and aluminum‐20 wt.% silicon alloys

Abstract

The microstructures and corrosion resistance of two as‐cast alloys, aluminum‐10 wt.% silicon hypoeutectic alloy and aluminum‐20 wt.% silicon (weight percent) hypereutectic alloy are investigated by conventional casting, the scanning electron microscope equipped with oxford X‐ray energy dispersive spectroscopy system and transmission electron microscope are applied for analysis. The results show that the microstructures change from the strip‐like into lump shape with the increase of silicon content from 10 % to 20 %. The electrochemical polarization curves prove that the aluminum‐20 wt.% hypereutectic silicon alloy had the better resistance with the corrosion potential of −1.414 V and corrosion current density of 5.41 ⋅ 10−5 ampere compared with the aluminum‐10 wt.% silicon hypoeutectic alloy.