Crack tip process zone domain switching in a soft lead zirconate titanate ceramic

• Published in: Acta materialia Vol. 55; no. 16; pp. 5538 - 5548
• Main Authors: Jones, Jacob L., Motahari, S. Maziar, Varlioglu, Mesut, Lienert, Ulrich, Bernier, Joel V., Hoffman, Mark, Üstündag, Ersan
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01-09-2007; Elsevier Science
• Subjects: Applied sciences; Ceramics; Exact sciences and technology; Ferroelectricity; Fracture; Fracture mechanics; Fractures; Lattice strain; Lead zirconate titanates; Mathematical models; Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology; Metals. Metallurgy; Preferred orientation; Spatial distribution; Switching; Toughness; Wakes; X-ray diffraction (XRD); X-ray diffraction (XRD); Toughness; Fracture; Ferroelectricity; Ceramics; Lead titanates; Rupture; Mechanical properties; X ray diffraction; Switching; Lead zirconates; Fracture toughness; Crack tip; Ceramic materials
• ISSN: 1359-6454; 1873-2453
• DOI: 10.1016/j.actamat.2007.06.012

Non-180° domain switching leads to fracture toughness enhancement in ferroelastic materials. Using a high-energy synchrotron X-ray source and a two-dimensional detector in transmission geometry, non-180° domain switching and crystallographic lattice strains were measured in situ around a crack tip in a soft tetragonal lead zirconate titanate ceramic. At
K
I
=
0.71
MPa
m
1/2 and below the initiation toughness, the process zone size, spatial distribution of preferred domain orientations, and lattice strains near the crack tip are a strong function of direction within the plane of the compact tension specimen. Deviatoric stresses and strains calculated using a finite element model and projected to the same directions measured in diffraction correlate with the measured spatial distributions and directional dependencies. Some preferred orientations remain in the crack wake after the crack has propagated; within the crack wake, the tetragonal 0
0
1 axis has a preferred orientation both perpendicular to the crack face and toward the crack front.