Transformation Plasticity of CeO2‐Stabilized Tetragonal Zirconia Polycrystals: II, Pseudoelasticity and Shape Memory Effect

Publisher Website
Google Scholar
Abstract
A macroscopic shape memory effect is demonstrated by first deforming a CeO2‐stabilized tetragonal zirconia polycrystal (Ce‐TZP) between the Mb and As temperatures and then recovering the shape change by heating above Ab. Shape changes effected above Ab are immediately recoverable during unloading, giving rise to a pseudoelastic behavior. Deformation texture is reversible when the shape strain recovers. Both Mb and Ab, along with the associated temperature range for these effects, are depressed to lower temperatures by grain refinement. Prior deformation widens the gap between the transformation temperatures. These observations demonstrate that the shape accommodation in Ce‐TZP arises from twinning and elastic distortions. The operation of pseudoelasticity and shape memory effect is rationalized in terms of martensitic nucleation statistics, the stability of thermoelastic martensite, and internal stresses at the martensitic interface. The implications on transformation plasticity and transformation toughening are explored.