Bouncing window for colliding nanoparticles: Role of dislocation generation.
Bouncing window for colliding nanoparticles: Role of dislocation generation.
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DOI：
10.1103/physreve.99.032904
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发表时间：
2019-03
期刊：
影响因子：
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通讯作者：
Maureen L. Nietiadi;E. N. Millán;E. Bringa;H. Urbassek
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文献类型：
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作者：
Maureen L. Nietiadi;E. N. Millán;E. Bringa;H. Urbassek
可用的宏观理论--如Johnson-Kendall-Roberts（JKR）模型--预测球形粒子以较小的碰撞速度v相互粘附;高于弹跳速度v_{B}，它们弹跳。我们使用分子动力学模拟的晶体纳米粒子，原子通过Lennard-Jones势相互作用的弹跳阈值的细节进行了研究。我们发现，弹跳速度强烈依赖于碰撞过程中的纳米粒子的取向;对于某些取向，纳米粒子坚持在所有的速度。弹跳对取向的依赖性是由位错活动过程中的能量耗散引起的。弹跳速度随着纳米颗粒半径的增加而减小，与JKR理论合理一致。对于存在弹跳的取向，纳米颗粒以更高的速度再次粘附，即熔合速度v_{f}，使得弹跳仅发生在有限的速度范围内-弹跳窗口。聚变速度与纳米粒子半径无关。
Available macroscopic theories-such as the Johnson-Kendall-Roberts (JKR) model-predict spherical particles to stick to each other at small collision velocities v; above the bouncing velocity, v_{b}, they bounce. We study the details of the bouncing threshold using molecular dynamics simulation for crystalline nanoparticles where atoms interact via the Lennard-Jones potential. We show that the bouncing velocity strongly depends on the nanoparticle orientation during collision; for some orientations, nanoparticles stick at all velocities. The dependence of bouncing on orientation is caused by energy dissipation during dislocation activity. The bouncing velocity decreases with increasing nanoparticle radius in reasonable agreement with JKR theory. For orientations for which bouncing exists, nanoparticles stick again at a higher velocity, the fusion velocity, v_{f}, such that bouncing only occurs in a finite range of velocities-the bouncing window. The fusion velocity is rather independent of the nanoparticle radius.