Most deformation twins in nanocrystalline face-centered cubic metals were observed to form from grain boundaries. The growth of such twins requires the emission of Shockley partials from the grain boundary on successive slip planes. However, it was statistically improbable for a partial to exist on every slip plane. Here, a dislocation reaction and cross-slip mechanism on the grain boundary was proposed that would supply a partial on every successive slip plane for twin growth. This mechanism could also produce a twin with a macrostrain smaller than that caused by a conventional twin.

Twinning Partial Multiplication at Grain Boundary in Nanocrystalline FCC Metals. Y.T.Zhu, X.L.Wu, X.Z.Liao, J.Narayan, S.N.Mathaudhu, L.J.Kecskés: Applied Physics Letters, 2009, 95[3], 031909