High plastic strains (4%) in 12mol%Ce-stabilized ceramics were produced by using a new thermo-mechanical process at temperatures below 450C. Transmission electron microscopic observations showed that abundant dislocation pile-ups were associated with a few martensitic laths in the deformed samples. The dislocation density increased with continued thermo-mechanical cycling. This suggested that dislocation multiplication was caused by high local stress concentrations ahead of martensitic laths during thermo-mechanical deformation. The generation and movement of dislocations introduced an extra plasticity in addition to the transformation plasticity that was caused by martensite. The movement of dislocations relaxed interface stresses at martensitic laths, prevented reverse martensitic transformations, and delayed cracking.

X.Zhe, C.Wang, A.Hendry: Journal of the American Ceramic Society, 1996, 79[6], 1726-8