Shape memory effect and pseudoelasticity behavior in tetragonal zirconia polycrystals: A phase field study

摘要

Martensitic tetragonal-to-monoclinic transformation in zirconia is a "double-edged sword", enabling transformation toughening or shape memory effects in favorable cases, but also cracks and phase degradation in undesirable scenarios. In stressed polycrystals, the transformation can burst from grain to grain, enabling stress field shielding and toughening in an autocatalysis fashion. This transformation strain can be recovered by an adequate thermal cycle at low temperatures (when monoclinic is stable) to provide a shape memory effect, or by unloading at higher temperatures (when tetragonal is stable) to provide pseudoelasticity.