Surface fracture behavior and subsurface damage of polycrystalline yttrium aluminum garnet ceramics in Vickers indentation

In this paper, the Vickers indentation experiments were carried out under different loads on the polished surface of polycrystalline yttrium aluminum garnet (YAG) ceramics to investigate the surface fracture behavior and subsurface damage under quasi-static conditions. The surface of polycrystalline YAG ceramic was corroded for intuitively observing the surface fracture behavior under quasi-static load, and the method of section polishing combined with chemical corrosion was used to examine the subsurface damage. The Johnson-Holmquist (JH-2) material model of polycrystalline YAG ceramics was established and imported into Abaqus software to simulate the process of Vickers indentation, so as to predict surface fracture behavior and subsurface damage depth under quasi-static load. The results show that the surface fracture behavior was divided into two stages with the increase of loads, that is, the fracture toughness value increased gradually and the fracture behavior was mainly transgranular fracture in the loading range of 0.05–0.3kgf. The fracture toughness value decreased obviously and fracture behavior was mainly intergranular fracture when the load range was 0.3-1kgf. The simulation values of surface fracture length and subsurface damage depth under different loads are highly consistent with the experimental results of Vickers indentation, the accuracy of the established simulation model was verified, which has an important guiding value for predicting the surface fracture behavior and subsurface damage in ultra-precision grinding of polycrystalline YAG ceramics.