Abstract A mechanical model of a metal nanopowder compaction is proposed. It takes into account the change in the shape of nanoparticles during mutual indentation, the action of surface tension, elastic stresses and plastic deformation of particles. The plastic deformation is the key point of compaction; the dislocation approach is used to incorporate the plasticity into the model. The model considers the stage of free relaxation, when the nanoparticles are mutually attracted due to the surface tension and mutually repulsed due to the elastic stresses, and the stage of compaction, when the interplay between elastic deformation and plasticity defines the mechanical response of the powder. The model provides a kinetic form of the constitutive equations for nanopowder and is intended for use in macroscopic modeling of the shock-wave processes in the calculation of installations for dynamic compaction of nanopowders to describe the local mechanical reaction and estimate the degree of compaction in each finite element. Molecular dynamics (MD) simulations of the dynamic compaction of Al nanopowders with particle diameters in the range of 6–30 nm are carried out. Comparison with the results of MD shows that the proposed model adequately describes both the relaxation stage and the powder compression stage. The effects of temperature, strain rate and nanoparticles piling are considered.

中文翻译：

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铝纳米粉体动态压缩塑性变形：分子动力学模拟和力学模型

摘要 提出了金属纳米粉体压实的力学模型。它考虑了相互压痕过程中纳米颗粒形状的变化、表面张力的作用、颗粒的弹性应力和塑性变形。塑性变形是压实的关键点；位错方法用于将可塑性纳入模型。该模型考虑了自由松弛阶段，即纳米颗粒因表面张力相互吸引并因弹性应力相互排斥，以及压实阶段，即弹性变形和塑性之间的相互作用定义了粉末的机械响应. 该模型提供了纳米粉末本构方程的动力学形式，旨在用于对纳米粉末动态压实装置计算中的冲击波过程进行宏观建模，以描述局部机械反应并估计每个过程中的压实程度。有限元。进行了粒径在 6-30 nm 范围内的 Al 纳米粉末的动态压实的分子动力学 (MD) 模拟。与 MD 结果的比较表明，所提出的模型充分描述了松弛阶段和粉末压缩阶段。考虑了温度、应变率和纳米粒子堆积的影响。