Contribution from Ferroelastic Domain Switching Detected Using X‐ray Diffraction to R ‐Curves in Lead Zirconate Titanate Ceramics

In Pb(Zr,Ti)O 3 ceramics, which are characterized by different magnitudes of coercive tensile stress, the ferroelastic domain switching induced during crack growth was measured using X‐ray diffraction, and was compared with the R ‐curve behavior. The following correlation was established: material with smaller coercive stress has a larger amount of domain switching, and a higher toughness increment in the R ‐curve. The half‐width of the process zone was determined for one of the four studied compositions from the spatial distribution of domain switching measured using X‐ray diffraction from synchrotron source. Its value, 60–80 μm, was in good agreement with the estimate from fracture mechanics.