Origin and evolution of a fivefold twin on the surface of a nickel alloy

At present, one thinks that fivefold twins (FTs) are formed from the multiple partial dislocations emitted from the grain boundaries. This results in that there are no reports on the deformation twinning of FTs from a single crystal. In this study, deformation twinning of an FT is performed from a single crystal, which is induced on the surface of an alloy under nanoindentation. The origin and evolution of an FT is elucidated on the surface of a nickel alloy. Incoherent twin boundaries (ITBs) play the most important role during the formation of an FT.