Estimated and Evaluated Residual Stress by Vickers Indentation in Several Structural Ceramics
Tarou TOKUDA, Takahiro DOTE, Rongguang WANG and Mitsuo KIDO
Abstract:In this study, residual stress was generated in several structural ceramics by sintering and grinding, then estimated using the Vickers indentation method. First, we investigated the appropriate pretreatment for measuring fracture toughness (basis value, KC), while prevently any influence of residual stress. This is important in estimating residual stress using the Vickers indentation method. Based on that value, the residual stress in Al2O3 and Si3N4 ceramics was estimated by the Vickers indentation method. Next, several problems in estimating residual stress using the indentation method on ZrO2 ceramics were discussed focusing on phase transformation. Results show that residual stress in Al2O3 and Si3N4 can almost be eliminated by annealing the specimen after hand grinding. Consequently, it is thought that this treatment method is effective for determining the basis value KC. The estimated residual stress value on Al2O3 and Si3N4 obtained by the Vickers indentation method at 98N corresponded closely to the values obtained by X-rays. Compared with Al2O3 and Si3N4, residual stress in ZrO2 estimated by the indentation method was larger than that found by the X-ray method. This is assumed to be the influence of phase transformation. Key Words:Ceramics, Residual stress, Fracture toughness, Vickers indentation, X-ray diffraction