Transformational Superplactisity is a phenomenon of an anomalous weakness of a polycrystalline material which undergoes a phase transformation while being subjected to a low deviatoric stress.
Most polycrystalline materials exhibit superplasticity of various degrees in a particular environment, for example, during temperature cycling of a material with anisotropic thermal expansion or during cycling of a composite through a solid-solid phase transformation. The large elongations in metals and alloys and increased creep rate in some ceramics are produced by imposing a small deviatoric stress on a transforming material. This phenomenon was also observed during a phase transformation structurally analogous to Earth's olivine-spinel phase transformation.

I begun investigating the superplactisity after taking my Generals Exam at MIT. A member of my scientific committee, Tom Jordan - then Head of the Department, asked a couple of questions on phase transformations as a main "sourse" of the density increase with depth. I would say that he inspired my interest in that area. Exchange of numerous e-mails with Slava Solomatov (now Professor at WUSTL) helped me a lot in understanding the phase transformations and their physics. Together with my thesis advisor Bradford Hager we investigated transformational superplasticity in application to Earth's polycrystallines to determine the factors and parameters it depends on, to estimate the amplitude of the softening at the deep phase change regions, and to analyze its possible impact on large-scale mantle flow. We presented results of this research in the GJI paper.