Dynamic Phenomena at Mode-I Crack Front in Silicon Simulated by Extended Molecular Dynamics

Analytical-solution-controlled molecular dynamics that can simulate atomic-scale phenomena around a crack front has been extended so that it can also simulate phenomena caused dynamically by elastic/plastic waves. The result of the simulation for monocrystalline silicon shows that a quasi-statically opening crack creates voids around the crack front and leaves dimples on the fractured surfaces as in cases of ductile fracture. On the other hand, elastic/plastic waves emitted from around the crack front change the above phenomena such that various surfaces, from smooth to very rough ones, result. A smooth surface is created by a Rayleigh wave that travels along fractured surfaces, creating new surfaces at its wavefront, while a rough surface is made by a chain mechanism wherein a void is created by wave-driven cross slip and this void, in turn, emits new waves which cause voids.