Effect of crystallographic orientation on the extrusion of silicon surface during an impact: Molecular dynamics simulation

Molecular dynamic simulation was applied in analyzing the effect of crystallographic orientation on the extrusion formation of silicon surface during the impact of a large silica cluster in dry and wet condition, respectively. The crystallographic orientation would have no obvious influence on the cross-section of crater created by the impact in either dry or wet conditions. The cross-section of crater appeared to be trapezoid shape and semicircular shape after the dry and wet impact, respectively. The inner layer of the crater after a wet impact was smoother than that after a dry impact. The extrusion patterns on the surfaces of (0 0 1)-, (0 1 1)- and (1 1 1)-oriented silicon single crystals had four, two, and threefold symmetries, respectively. Moreover, the critical velocity of the extrusion formation on Si(1 1 0) substrate under the dry impact would be the largest, followed by Si(1 1 1) substrate, and Si(0 0 1) substrate was the smallest. The critical velocity reached to its minimum when the impact had an incidence angle of 45°. However, the crystallographic orientation would have no influence on the critical velocity of the extrusion under the wet impact, and the critical velocity reached its minimum at the incidence angle of 30°.