Dynamic behavior of metals under laser-induced microparticle impact

Abstract

It is challenging to assess the dynamic mechanical behavior of metallic materials under ultra-high strain rates. In this study, we obtained the dynamic behavior of metallic materials, including copper, aluminum alloy, and steel alloy, at strain rates ranging from 10³ to 10⁸ s^-1 by laser-induced particle impact test (LIPIT) experiments and numerical simulations. By measuring the energy dissipation of the microparticles and the impact-induced craters of the metallic materials, we determined the dynamic hardness of the metallic materials at different strain rates. We observed that the strain-rate sensitivity of copper hardness increases significantly after exceeding the critical strain rate, which should be ascribed to the transformation of deformation mechanisms from the thermally activated mechanism to the dislocation drag mechanism at ultra-high strain rates. Based on the relationships between hardness and strain rate, we proposed a modified Johnson-Cook constitutive model, which is capable of describing the dynamic behavior of metallic materials under strain rates ranging from 10³ to 10⁸ s^-1. This study presents an effective method for assessing the dynamic mechanical behavior of metals under a wide range of strain rates.