Effect of molten zone ablated by femtosecond laser on fracture toughness of oxide ceramics

In this paper, an ultra-sharp V-notch was produced by femtosecond laser on the green bodies of 3Y-TZP, Al2O3 and 8Y-FSZ, respectively. After sintering, the fracture toughness of those ceramic samples was tested by single edge V-notched beam (SEVNB) method. For comparison, the fracture toughness of ceramic samples with an ultra-sharp V-notch ablated by femtosecond laser directly on the sintered test bars was also determined as a regular testing route. The results reveal that the two different preparation methods of ultra-sharp V-notches can obtain the actual fracture toughness of 3Y-TZP, Al2O3 and 8Y-FSZ. It proves that the influence of thermal effect of ablation process caused by femtosecond laser in front of the notch tip on the fracture toughness can be negligible.