Anisotropy of Fracture Toughness of Stabilized Zirconia Investigated by Nano-Identation Method

Abstract

Nano-indentation tests with a Vickers-type diamond tip were carried out on the {100} surface of a single crystal of 10 mol% yttria-stabilized zirconia (10YSZ), (Y₂O₃)_0.1(ZrO₂)_0.9. By changing the contact angle of the indentation tip against the single crystal sample, the fracture toughness of 10YSZ was investigated as a function of the crystal orientation from <100> to <110> on the {100} surface. It was empirically shown that the fracture toughness of 10YSZ is anisotropic. The fracture toughness of 10YSZ was lowest in the direction of <100> among investigated orientations. This result suggests that mechanical failures in 10YSZ may occur preferentially along the direction of <100>.