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运用Compass力场的分子动力学方法,研究了含氧化层的纳米铝球颗粒熔点的变化规律。通过对铝球升温,探索了铝球粒径及氧化层厚度对其熔点的影响,以及含氧化层纳米铝球颗粒的熔化过程。铝粉粒径很小时,其表面形成的氧化层较薄,热膨胀作用使氧化层逐渐破裂。当粒径较大及氧化层较厚时,若温度升至氧化层熔点,由于铝球内核压力的协同作用导致氧化层突然破裂,铝原子与空气接触发生爆燃。结果表明:同一粒径的纳米铝粉,氧化层厚度越厚,氧化层熔化时爆裂现象越严重。
The molecular dynamics method of Compass force field is used to study the variation of the melting point of nano-alumina ball with oxide layer. By heating the aluminum ball, the effect of particle size and thickness of the aluminum ball on its melting point and the melting process of the oxide-containing nano-aluminum ball particles were explored. When the particle size of aluminum powder is very small, the oxide layer formed on the surface is thinner, and the thermal expansion gradually causes the oxide layer to crack gradually. When the particle size is larger and the oxide layer is thicker, if the temperature rises to the melting point of the oxide layer, the oxide layer suddenly breaks down due to the synergistic effect of the aluminum sphere core pressure, and the aluminum atoms deflagrate upon contact with the air. The results show that the thicker the oxide layer with the same particle size of nanoaluminum powder, the more serious the rupture occurs when the oxide layer melts.