Calculation of crack tip phase transformation zones with the weight function method

Stabilized Zirconia ceramics can undergo a stress-induced tetragonal-to-mon oclinic phase transformation. This way, a transformation zone with compress ive stresses develops around crack tips, leading to an increase in fracture toughness. The increase in fracture toughness depends on the size of the t ransformation zone. Therefore, the ability to compute the phase transformat ion zone at a crack tip is crucial to determine the transformation tougheni ng due to phase transformation. In the case of subcritical phase transforma tion, the crack tip phase transformation zone has been calculated using the finite element method. In some Zirconia ceramics, such :Ls ceria-stabilize d TZP Zirconia ceramics, an autocatalytic phase transformation takes place, leading to large, elongated transformation zones. As this supercritical ph ase transformation cannot be computed with finite elements, several methods for investigating supercritical phase transformation have been developed. In this paper, a method based, on the weight function method will be descri bed. (C) 1999 Elsevier Science B.V. All rights reserved.