It was noted that the speeds of all observed dislocations in crystals were subsonic, and that there was a general view that the speed of dislocations could not be increased above the speed of sound because the energy required would be infinitely large. However, molecular dynamics simulations had shown that it was possible to generate dislocations with an initial speed that was greater than the velocity of sound in solids. This raised the question of what would happen when a supersonic dislocation met other defects in its path. Molecular dynamics simulations were made here of the interaction of a transonic dislocation with subsonic dislocations or with point-defect clusters. The results showed

that a vacancy cluster, such as a void, had an insignificant slowing effect upon the transonic dislocation, while a subsonic dislocation slowed the transonic dislocation to subsonic speeds. In some cases, the subsonic dislocation (or a subsonic part of a transonic dislocation) could overcome the traditional sound barrier.

Interaction of a Transonic Dislocation with Subsonic Dislocation and Point Defect Clusters. S.Q.Shi, H.Huang, C.H.Woo: Computational Materials Science, 2002, 23[1-4], 95-104