Paper Title
Effect of Cooling Rate and 2 Wt % Silicon Addition on Microstructure and Mechanical Properties of Az91 Mg Alloys

Abstract
In this study, the effects of silicon addition and different cooling rates on the microstructure and mechanical properties of AZ91 magnesium alloys which are used in various industries have been investigated. For this aim, the AZ91 alloys have been poured to a step-like mold. Additionally, silicon element has been added in the 2 wt. % to AZ91 to obtain AZ91+2 wt. % Si alloy and changes of different cooling rates have been observed. Results showed that hardness of alloys has been increased with cooling rates increase and silicon addition to this alloy. Also, with silicon addition in the 2 wt. % to AZ91 that have been occurred Mg2Si phases. Depending on change in the cooling rate, phase of Mg17Al12 has been changed and thinner grains have been obtained. The distance between the α-Mg particles is narrowed. Index Terms- AZ91, Cooling Rate, Mg Alloys, Mg2Si, Microstructure.