Microstructure and Creep Behavior of CaO added Mg-Al-Si Alloys

For automotive parts used at elevated temperatures, such as transmission cases and engine blocks, it is necessary to improve the creep resistance of magnesium alloys. For this reason, various magnesium alloys have been developed for elevated temperature applications. In this study, the microstructure and creep behavior of CaO added Mg-Al-Si alloys (Mg-5.0Al-0.7Si, Mg-5.0Al-0.7Si-0.5CaO, Mg-5.0Al-0.7Si-0.5CaO-0.3Sr) were investigated. The microstructures were observed by OM, SEM and TEM. To evaluate the mechanical properties, tensile tests were carried out at room and high temperature, and creep tests were performed at 150 degrees C with applied loads from 50 to 80 MPa.