Twinning mechanism via synchronized activation of partial dislocations in face-centered-cubic materials

  In situ straining in a high-resolution transmission electron microscope and molecular dynamics simulations reveal a new deformation twinning mechanism in the face-centered-cubic structure. A twin forms via the simultaneous and cooperative activation of different Shockley partial dislocations on three (1 1 1) layers. The synchronized slip produces a zero net Burgers vector; such twining relieves local stress concentration in a shear confined to adjacent atomic layers, but induces no macroscopic shape change of the surrounding crystal.