Effects of Mold Rotation Speed and Cast Thickness on the Microstructure and Mechanical Properties of AZ80 Prepared by Centrifugal Casting

Centrifugal casting is an accepted method for the large-scale production of alloys and composites products. However, up to now, very few studies have been done on the fabrication of the Mg alloys utilizing this technology, especially the higher aluminum containing magnesium alloys. Therefore, an investigation of parameters influencing the properties of the Mg alloys using this approach is necessary. This study aims to investigate the effects of centrifugal casting variables on the microstructure and mechanical properties of AZ80 magnesium (Mg) alloy. The samples were cast with different centrifugal speeds of 800, 1000, and 1200 rpm. After optimizing the centrifugal speed, the effect of thickness on the properties of the samples was investigated. Besides, the mechanical properties of the samples were evaluated using microhardness, tensile, and compression tests. The microstructure and fracture surfaces of samples were analyzed using optical microscopy (OM) and scanning electron microscopy (SEM) images. OM images indicated that the microstructure of samples was composed of alpha-Mg phase and gamma-Mg17Al12 precipitates. A microstructural evolution was observed as a function of the diameter of the samples; i.e., the volume fraction of the gamma-Mg17Al12 precipitates decreased by increasing the diameter of the specimens. The findings also illustrated that for all samples, the highest mechanical properties were achieved at the inner layers due to the presence of more gamma-Mg17Al12 precipitates. On the other hand, the outer layers owing to their finer grains represented higher mechanical properties compared with the middle layer.