The cubic-to-β martensitic transformation in ZrO₂-Sc₂O₃

Abstract

The nature of the cubic-to-β (c-β) transformation and the microstructure of theβ-phase were examined in ZrO₂-10.5 and 12.5 mol % Sc₂O₃ alloys. The c -β transformation is induced during cooling from the high-temperature cubic phase region by martensitic transformation. The microstructure of theβ-phase usually has a herring-bone appearance, which is made of a unique array of four orientation variants. Two types of interfaces are formed in the structure; long straight interfaces and short interfaces. The former and the latter interfaces are nearly parallel to the {011} _β and {012} _β type planes, respectively, which correspond to the {001}_c and {011}_c planes in the parent cubic phase. The {011} _β and {012} _β type interfaces are fully coherent, low-energy interfaces. The herring-bone structure is likely to be a favourable one for minimizing the strain energy and interfacial energy associated with the c -β transformation, which is a characteristic microstructure developed by martensitic transformation.