Supersonic Impact of Metallic Micro-particles
Abstract
Understanding material behavior under high velocity impact is the key to addressing a variety of fundamental questions in areas ranging from asteroid strikes and geological cratering to impact-induced phase transformations, spallation, wear, and ballistic penetration. Recently, adhesion has emerged in this spectrum since it has been found that micrometer-sized metallic particles can bond to metallic substrates under supersonic-impact conditions. However, the mechanistic aspects of impact-induced adhesion are still unresolved. Here we study supersonic impact of individual metallic microparticles on substrates with micro-scale and nanosecond-level resolution. This permits the first direct observation of a material-dependent threshold velocity, above which the particle undergoes impact-induced material ejection and adheres to the substrate. Our finite element simulations reveal that prevailing theories of impact-induced shear localization and melting cannot account for the material ejection. Rather, it originates from the propagation of a pressure wave induced upon impact. The experiments and simulations together establish that the critical adhesion velocity for supersonic microparticles is proportional to the bulk speed of sound.
Keywords
Cite
@article{arxiv.1612.08081,
title = {Supersonic Impact of Metallic Micro-particles},
author = {Mostafa Hassani-Gangaraj and David Veysset and Keith A. Nelson and Christopher A. Schuh},
journal= {arXiv preprint arXiv:1612.08081},
year = {2016}
}