It was recalled that deformation twins often met each other to form multi-fold twins in nanostructured face-centered cubic metals. Two types of mechanism were proposed here for the nucleation and growth of four different single and multiple twins. These mechanisms permitted the continuous generation of twinning partials for the growth of the twins after nucleation. A relatively high stress or high strain rate was required to activate the mechanisms; thus making them more prevalent in nanocrystalline materials than in coarse-grained ones. Experimental observations supported the proposed mechanisms.

Formation of Single and Multiple Deformation Twins in Nanocrystalline FCC Metals. Y.T.Zhu, J.Narayan, J.P.Hirth, S.Mahajan, X.L.Wu, X.Z.Liao: Acta Materialia, 2009, 57[13], 3763-70