Fig. 4: High-resolution TEM observations of an impact-induced bonded interface.
a Cross-sectional SEM image of a 40 µm bonded Al particle to Al at 821 m/s along with the TEM images at the interface. High magnification views of the specific locations from the impact center to the edge showing b native oxide layers and localized bonding, c fractured oxide layers and few-hundred-nanometer-long metallic bonds, d–f 5-µm long continuous bonding with isolated oxide particles and debris, g continuous bonding interrupted by fractured oxide layers, h extruded metal bonding with both particle and substrate and a transition from i the last detectable bonded region to j non-bonded region close to the edge. The native oxide layers, particles, and debris are highlighted with orange lines and arrows, and the regions with no discernable native oxide are highlighted with blue lines and arrows.
