Abstract
Gravity die castings of AZ31B magnesium alloy with mechanical vibration were conducted. Columnar rod specimens (20mmφ × 30mmL) were cast under various vibration conditions to investigate the effects of each vibration parameter, such as frequency, amplitude, velocity and acceleration, on cooling rate and grain refinement of gravity die castings. There was poor correlation between cooling rate and frequency. Under the same frequency conditions, the cooling rate indicated different values according to other vibration conditions. As well as the frequency, amplitude and velocity showed poor correlation with cooling rate. However, acceleration correlated clearly with cooling rate. The cooling rate increased with increase acceleration, and the same acceleration conditions led the similar cooling rate regardless of other vibration conditions. On the other hand, the grain size was most affected by the amplitude. When the amplitude was 0.4mm (the maximum value in this study), the grains became fine. In these specimens, grains less than 100μm and of several hundred μm were found to coexisted.
