The dynamic process whereby an edge dislocation in face-centered cubic Cu by-passed an impenetrable precipitate was investigated by means of molecular dynamics simulation. A mechanism that was quite different from the Orowan mechanism was observed, where a dislocation left 2 prismatic loops near to a precipitate (the Hirsch mechanism). It was found that the critical stress for the Hirsch mechanism was almost the same as the Orowan stress, while spatial inhomogeneity of the shear stress was essential to the Hirsch mechanism. It was also found that repetition of the Hirsch mechanism did not increase the critical stress.

Dynamics of a Dislocation Bypassing an Impenetrable Precipitate - the Hirsch Mechanism Revisited. T.Hatano: Physical Review B, 2006, 74[2], 020102 (4pp)