Reliable evaluation of fracture toughness in ceramics via nanosecond laser notching method

As a new type of notching approach, laser notching method always neglecting the significant impact of equivalent notch angle ( θ ) on fracture toughness results, although it has successfully solved the problem of introducing sharp enough V-notches in ceramics. Here, porous ZrB 2 and dense ZrB 2 -SiC ceramics are taken as the experimental targets, and the effect of θ on the fracture toughness values of these typical ceramics is investigated. To measure the fracture toughness accurately, the θ should be less than 60°, namely, the laser notch depth should be larger than the traditional U-groove root radius. Nanosecond laser notching method shows great advantages in high notch depth (easy to reach 300 μm) and sufficient accuracy (tip radius less than 1 μm), and is deemed to have a good prospect of standardization.