Deformation twinning was observed in room-temperature rolled nanocrystalline Ni. The growth of the deformation twins via the emission of partial dislocations from a grain boundary was examined in detail. Partial dislocations on neighbouring slip planes may migrate for different distances and then remain in the grain interior, leading to the formation of a step-like twin boundary. With continued twin growth, the twin boundaries become gradually distorted and lose their coherent character due to accumulated high stresses. Moreover, it was proposed that micro-twins may form near such twin boundaries due to the emission of partial dislocations from the twin boundary.

Growth of Deformation Twins in Room-Temperature Rolled Nanocrystalline Nickel. X.Y.Zhang, X.L.Wu, A.W.Zhu: Applied Physics Letters, 2009, 94[12], 121907