R-Curve Behavior and Flexural Strength of Zirconia-toughened Alumina and Partially Stabilized Zirconia Composite Laminates

Reference	Presenter	Authors (Institution)	Abstract
09-124	Marcelo Daniel Barros	Blaese, D.(Hamburg University of Technology); Benitez, T.(Federal University of Santa Catarina); Barros, M.D.(Federal University of Santa Catarina); Jelitto, H.(Hamburg University of Technology); Travitzky, N.(University of Erlangen-Nuremberg); Hotza, D.(Federal University of Santa Catarina); Janssen, R.(Hamburg University of Technology);	A composite-laminate formed by thick layers (~320 µm) of zirconia-toughened alumina (ZTA) with thin (~50 µm) interlayers of zirconia partially stabilized (Y-PSZ) has been fabricated by tape casting and pressureless sintering. Fracture behavior and strength has been investigated and compared to a monolithic reference, e.g. a stack of zirconia-toughened alumina (ZTA) without interlayers. The fracture behavior has been analyzed using stable crack growth in V-notched specimens loaded in 3-point bending. The ZTA+Y-PSZ composite laminate presented a rising crack resistance with maximum values between 6 and 14 MPa.${\mathrm{m}}^{\raisebox{1ex}{$1$}\!\left/ \!\raisebox{-1ex}{$2$}\right.}$. In contrast, the monolithic ZTA laminate shows a plateau R-curve behavior at 2.7 MPa.${\mathrm{m}}^{\raisebox{1ex}{$1$}\!\left/ \!\raisebox{-1ex}{$2$}\right.}$. Several toughening mechanisms were identified in the ZTA+Y-PSZ composite laminate, such as, crack arrest/slow down, micro cracking and bifurcation. These toughening mechanisms are most likely caused by high tensile residual stresses that were estimated theoretically.
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