A grain boundary transition from a bilayer to an intrinsic (nominally clean) boundary was observed in Si-Au. An atomically abrupt transition between the two complexions (grain boundary stabilized phases) implied the occurrence of a first-order interfacial phase transition associated with a discontinuity in the interfacial excess. This observation supports a grain-boundary complexion theory with broad applications. This transition was atypical in that the monolayer complexion was absent. A model was proposed to explain the bilayer stabilization and the origin of this complexion transition.

A Grain Boundary Phase Transition in Si-Au. S.Ma, K.M.Asl, C.Tansarawiput, P.R.Cantwell, M.Qi, M.P.Harmer, J.Luo: Scripta Materialia, 2012, 66[5], 203-6