Experiment and dynamic analysis of grain refining effects with vibration and chilling

Mechanism of grain nucleation and detachment on chilling metal surface by vibration was examined using NH₄Cl-70H₂O analogue alloy. Experimental results reveal that acceleration can be used as the e-valuation criteria of grain detachment under a fixed frequency. Effects of grain detachment were enhanced with increasing in acceleration. However, it should be noted that, at a constant vibration acceleration, grain detachment was restrained with the increase of vibration frequency. A vibration dynamic model was proposed to describe the effects of vibration parameters on the grain detachment behavior, which shows that the frequency response curve is determined by the co-action of viscous drag force with sympathetic vibration effects.