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arXiv · 1612.08081

Supersonic Impact of Metallic Micro-particles

Mostafa Hassani-Gangaraj·David Veysset·Keith A. Nelson·Christopher A. Schuh
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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.

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Mostafa Hassani-Gangaraj, David Veysset, Keith A. Nelson, Christopher A. Schuh. 2016-12-23. Supersonic Impact of Metallic Micro-particles. https://arxiv.org/abs/1612.08081

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