Compositional Dependence of <scp> <i>R</i> </scp> ‐curve Behavior in Soft <scp> <scp> Pb(Zr _{1− <i>x</i>} Ti _<i>x</i> )O ₃ </scp> </scp> Ceramics

Abstract

The compositional dependent fracture behavior of soft PZT ( Pb 0.99 Ba 0.01 (Zr 1− x Ti x ) 0.98 Nb 0.02 O 3 ) ceramics in the vicinity of the morphotropic phase boundary was characterized using compact‐tension specimens. The compositions with 0.40 ≤ x ≤ 0.55 displayed an increasing fracture resistance with crack extension ( R ‐curve behavior). It was observed that the rhombohedral composition and the compositions near the morphotropic phase boundary showed the largest toughness enhancement. R ‐curve behavior was found to be influenced by the ferroelastic coercive stress, saturated remanent strain, and elastic modulus, which were experimentally measured for each composition. X ‐ray diffraction measurements were performed and compared to the fracture results to investigate the impact of phase and lattice distortion on ferroelastic toughening behavior.