Influence of Preparation Methods on Anti-corrosion Performance of Alloy AZ91D+1.0%Sm

The influence of preparation methods (vacuum melting and ordinary melting)on micro-structure and corrosion resistance property of AZ91D+1.0% Sm alloy was studied by XRD,SEM with EDS,corrosion weightlessness experiment and electrochemical polarization curves,also the corrosion mechanism was analyzed. The results showed that a new phase Al3Sm in the ordinarily melted alloy was formed based on vacuum melted α-Mg,β-Mg17Al12 and Al2Sm. The rod-shaped Al3Sm had certain fragmentation effect on matrix microstructure,the corrosion rate of ordinarily melted alloy was about 35 times that of vacuum melted alloy. In contrast,the vacuum melted alloy had higher self corrosion potential,lower corrosion current density and bigger Tafel slope. So using vacuum melting can improve the anti-corrosion performance of alloys.