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摘要: 用分子动力学方法模拟计算了在冲击波加载条件下,单晶铁中的结构相变(由体心立方结构相到六角密排结构相),相互作用势采用铁的嵌入式原子势(EAM),单晶铁样品的尺寸为28.7 nm22.9 nm22.9 nm,总原子数为1.28106个。通过推动一个运动活塞对静止靶的作用来产生冲击压缩,加载方向沿单晶铁的[100]晶向。通过对原子位置的追踪,揭示了铁的冲击相变机制,计算结果表明相变机制包括两步:首先是在{011}面上的原子受到沿〈100〉晶向的压缩,使{011}面转化成正六角形密排面;然后是在{011}面上原子沿〈0-11〉晶向的滑移,完成由bcc结构到hcp结构的相变。同时发现滑移面只出现在与冲击波加载方向平行的(011)和(0-11)面上。Abstract: Shock-induced phase transformation (body-centered cubic phase to hexagonal close-packed phase) in single crystal iron has been investigated by means of molecular dynamics (MD) simulations using an embedded atom method (EAM) potential. The simulated dimension is 28.7 nm22.9 nm22.9 nm in size with 1.28106 atoms. The shock wave is generated by using a piston impact on the sample along the [100] direction. By analyzing the motion history of atoms under shock compression, the phase transformation mechanism has been outlined. The simulation results show that the phase transformation mechanism contains two steps: the atoms on the {011} planes are compressed along the 〈100〉 direction to form a hexagon in the first step, and then the atoms on {011} planes in the 〈0-11〉 direction are slipped to create the hcp structure in the second step. The results also show that the slip planes are only the (011) and (0-11) planes which are parallel with the shock wave propagation.
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Key words:
- phase transformation /
- shock wave /
- molecular dynamics
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