Internal Mechanism Analysis of Modeling on Particles Size Distribution Characteristics of Impact Attrition Beryllium Powders

摘要:

基于铍（Be）冲击制粉颗粒的形貌特征，建立了一个描述Be粉颗粒尺寸分布的物理模型，该模型仅含一个物理意义明确的参数。模型中考虑了2种重要的内在影响机制：具有不同初始动能的颗粒在完成冲击后的存在状态应该遵从Maxwell-Boltzmann分布，即大颗粒具有高的能量，状态不稳定，在冲击过程中容易碎成小颗粒，这一影响可以用颗粒尺寸的负指数函数来描述；获得低表面能的倾向又使得颗粒尽可能具有大的体积，这一影响可以用颗粒尺寸的立方函数来描述。实际的颗粒尺寸分布是这2种影响竞争的结果。计算结果与实验数据符合得很好

Abstract:

Based on the particle morphology of beryllium (Be) powders produced by impact attrition, a physics model has been established for describing the particle size distribution, which has only one parameter with the definite physical meaning. Two important internal mechanisms are considered: firstly, the distribution of existing state of particles with different original kinetic energy should obey the Maxwell-Boltzmann distribution after impacting, which means that big particles are unstable for their being at higher energy level, therefore they are easy to be fractured into smaller pieces in impact attrition process, and this influencing factor can be described as the negative exponential function of particles size; secondly, the tendency to remain low surface energy requires that Be powders should keep big volume as much as possible, and this influencing factor is defined as the cube function of particles size. The actual size distribution of Be particles is resulted from the competition between these two factors. Calculating result from the model is in good agreement with data from measurement