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The crystal detachment behaviors from a chilling solid surface with vibration were investigated using a transparent NH4Cl-70%H2O alloy.The nucleation experiments of NH4Cl-70%H2O alloy were performed on a chilling surface generator with various vibration frequency from 20 to 1 000 Hz and vibration acceleration from 10 to 100 m/s2.The results indicate that the crystal detach rate increases and the grains are refined with increasing vibration acceleration under a certain vibration frequency.It is interesting to note that,when the frequency is 50 Hz,acceleration is 100 m/s2,the crystal detach rate increases sharply and the grain refinement effect is strengthened.A special grain refinement phenomenon can be observed,when the vibration acceleration and frequency are up to a critical value.A power-based definition was introduced in order to describe the relationship between the vibration parameters and imposed power on the system.It is found that a power criterion exists for the grain refinement in the current system.
The crystal detachment behaviors from a chilling solid surface with vibration were investigated using a transparent NH4Cl-70% H2O alloy. The nucleation experiments of NH4Cl-70% H2O alloy were performed on a chilling surface generator with various vibration frequencies from 20 to 1 000 Hz and vibration acceleration from 10 to 100 m / s2. the results indicate that the crystal detach rate increases and the grains are refined with increasing vibration acceleration under a certain vibration frequency. It is interesting to note that when the frequency is 50 Hz, acceleration is 100 m / s2, the crystal detach rate increases sharply and the grain refinement effect is strengthened. A special grain refinement can be observed, when the vibration acceleration and frequency are up to a critical value. A power-based definition was introduced in order to describe the relationship between the vibration parameters and imposed power on the system. It is found that a power criterion exists for the grain refinem ent in the current system.