振动条件下的晶粒弥散细化效应及其能量判据

Scattering Phenomenon and Its Energy Criterion for Grain Refinement under Vibration

采用透明模型合金NH4Cl-70%H2O考察不同振动条件下激冷表面的激发形核特性及晶粒剥离行为。实验结果表明:振动频率f一定时,晶粒的剥离速度与细化程度随振动加速度a的增加而增加。基于能量的定义用来描述实验中振动参数和能量之间的关系,实验发现晶粒的细化效果存在能量准则,并给出细化晶粒的优化参数和判据为a2/f≥200m2/s3。

The crystal detachment behaviors from a chilling solid surface with vibration were investigated using a transparent NH4Cl-70 wt% H2O alloy. The results indicate that the crystal detach rate increases and the grains refine with the increase of vibration acceleration under a certain vibration frequency. A power-based definition was introduced 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 effects. A phenomenon of scattering crystal refinement effect can be observed in the current system when a condition of a2/f≥200 m2/s3 is satisfied.