Using high-resolution transmission electron microscopy, a new deformation-twinning mechanism, zero-strain twinning via nucleation and the migration of a Σ3{112} incoherent twin boundary was observed in polycrystalline Ag films. This twinning mechanism produced a near-zero macroscopic strain because the net Burgers vectors either equalled zero or were equivalent to a Shockley partial dislocation. This observation provided new insight into the understanding of deformation twinning and confirmed a previous hypothesis: that de-twinning could be accomplished via the nucleation and migration of Σ3{112} incoherent twin boundaries. The zero-strain twinning mechanism may be unique to low staking fault energy metals with implications for their deformation behavior.

High Resolution Transmission Electron Microscope Observation of Zero-Strain Deformation Twinning Mechanisms in Ag. L.Liu, J.Wang, S.K.Gong, S.X.Mao: Physical Review Letters, 2011, 106[17], 175504