DISLOCATION-RELATED PLASTICITY OF CERIA-STABILIZED ZIRCONIA POLYCRYSTALS

Much higher plastic strain of 4% in Ce-TZP ceramics was produced by a novel thermal-mechanical process below 450 degrees C, Observation by T EM showed that there were abundant dislocation pile-ups associated wit h a few martensitic laths in the deformed samples, The density of disl ocations increased with thermal-mechanical cycles, These suggested tha t dislocation multiplication was caused by the high local stress conce ntration in front of a martensitic lath during the thermal-mechanical deformation, The generation and movement of dislocations introduced ex tra plasticity beside the transformation plasticity caused by martensi te, Meanwhile, movement of dislocations relaxes the interface stress a t martensitic laths to prevent reverse martensitic transformation and early cracking of the specimens, The results are discussed in terms of thermal-mechanical action and dislocation multiplication.