抄録
The effect of shot-peening crack initiation and propagation of partially stabilized zirconia, PSZ, was investigated. The X-ray results showed that shot-peening could introduce large compressive residual stress at surface. The residual stress were -1400 MPa and -1800 MPa at depth from the surface of Oum and 20μm, respectively. The X-ray results also showed that shot-peening induced phase transformation from 'tetragonal' to 'monoclinic'. This implied that the large residual stress mainly introduced due to the local volume expansion generated by phase transformation. As a result, apparent Vickers hardness HV and fracture toughness K_<IC> of PSZ were improved by approximately 3% and 258%, respectively. Furthermore, the bending strength of specimen having a semi-elliptical surface crack increased significantly. Especially, the peened specimen having a crack with surface length < 65 μm fractured from the site other than the pre-crack. Thus, introduction of large compressive residual stress by shot-peening is effective technique for preventing crack initiation and propagation in PSZ.
