Department of Mechanical and Industrial Engineering, University of Massachusetts, Amherst, Massachusetts, 01002, USA.
Department of Physics, University of Massachusetts, Amherst, Massachusetts, 01002, USA.
Sci Rep. 2017 Jul 11;7(1):5073. doi: 10.1038/s41598-017-05104-7.
Metallic microparticles can acquire remarkable nanoscale morphologies after experiencing high velocity collisions, but materials science regarding the extreme events has been limited due to a lack of controlled experiments. In this work, collision dynamics and nonlinear material characteristics of aluminum microparticles are investigated through precise single particle collisions with two distinctive substrates, sapphire and aluminum, across a broad range of collision velocities, from 50 to 1,100 m/s. An empirical constitutive model is calibrated based on the experimental results, and is used to investigate the mechanics of particle deformation history. Real-time and post-impact characterizations, as well as model based simulations, show that significant material flow occurs during the impact, especially with the sapphire substrate. A material instability stemming from plasticity-induced heating is identified. The presented methodology, based on the use of controlled single particle impact data and constitutive models, provides an innovative approach for the prediction of extreme material behavior.
金属微颗粒在经历高速碰撞后可以获得显著的纳米级形态，但由于缺乏受控实验，关于极端事件的材料科学受到限制。在这项工作中，通过使用两种不同的基底（蓝宝石和铝）以精确的单颗粒碰撞，在 50 至 1100m/s 的广泛碰撞速度范围内，研究了铝微颗粒的碰撞动力学和非线性材料特性。基于实验结果，对经验本构模型进行了标定，并将其用于研究颗粒变形历史的力学特性。实时和碰撞后特性以及基于模型的模拟表明，在碰撞过程中会发生显著的材料流动，特别是与蓝宝石基底碰撞时更是如此。确定了一种源于塑性诱导加热的材料不稳定性。所提出的方法基于使用受控的单颗粒冲击数据和本构模型，为预测极端材料行为提供了一种创新方法。
