Fracture toughness of 3Y‐TZP ceramic determined by modified SCF method based on femtosecond laser

Abstract

AbstractIn this work, the femtosecond laser was used to replace the traditional indentation to process ultra‐sharp defects on the test bars for the fracture toughness testing of 3 mol% yttria‐stabilized tetragonal zirconia polycrystals (3Y‐TZP) ceramic materials by a modified SCF method. Finite element (FE) analysis shows that the positions of the maximum stress on the crack tip of the two types of defects are almost the same. Thus, the fracture toughness is calculated based on classical beam deflection theory by comparing their stress intensity factors. Results show that the ratio of the stress intensity factors almost keeps constant when the length and depth of the defects are controlled in a certain range. 3Y‐TZP ceramic material is used as a typical material to study fracture toughness for the verification of this method. The fracture toughness of 3Y‐TZP ceramics determined by this method is 4.4 MPa·m1/2 which coincides with the fracture toughness values tested by traditional SCF method, SEPB method, and SEVNB method. This method exhibits an obvious advantage in good high accuracy and operability for reliable fracture toughness testing of structural ceramics with a smaller defect.