LAUSR

Abstract In this paper, we aim at determining the actual fracture toughness of three difference yttria concentrations (3 mol%, 5 mol% and 8 mol%) zirconia ceramics by single-edge V-notched beam (SEVNB) method. The notch root radius (ρ≈0.25 μm) introduced by femtosecond laser is smaller than the grain size of 3YSZ. As obtained KIc values for the three zirconia samples are 4.4±0.12, 2.8 ±0.11 and 1.6±0.05 MPa m1/2 for 3YSZ, 5YSZ and 8YSZ, respectively. However, for a notch root radius of 9 µm cut by a razor blade, the KIc value of 3YSZ is 6.2±0.47 MPa m1/2. The volume fraction of m-ZrO2 on fractured surface determined by XRD is found to be nearly equal to that of SENB method. Specifically, the load-deflection curves of SEVNB method under the loading rate of 0.05 mm/min, 0.03 mm/min and 0.01 mm/min exhibit a stable crack propagation behavior.