In situ phase transformation of Laves phase from Chi-phase in Mo-containing Fe-Cr-Ni alloys

An in situ phase transformation of the Chi (chi) phase to the Laves phase was observed in a Fe-Cr-Ni-Mo model alloy. The morphology, composition, and crystal structure of the chi and Laves phases, and their orientation relationship with the matrix austenite phase were investigated. The resulted Laves phase has larger lattice mismatch with the matrix phase than the chi phase, leading to the increase of local strain fields and the formation of dislocations. This finding is helpful to understand the precipitation behavior of the intermetallic phases in the Mo-containing austenitic stainless steels. (C) 2015 Elsevier B.V. All rights reserved.