回転曲げにおけるセラミック/金属接合体の疲労特性

抄録

In this study, fatigue properties and initial strengths of ceramic/metal joints under cyclic rotary bending stress were investigated using the Ono’s rotary bending fatigue test machine. The initial strengths measured using this machine were compared to the 4-point bending strengths. The relationship between the applied stress and the fatigue life was discussed in terms of the S-N curve. Furthermore, SEM and EPMA observations of the fracture surfaces and the cross sections made the mechanism of fatigue fracture clear. The main results obtained are summarized as follows. (1) The initial strengths measured using the Ono’s rotary bending fatigue test machine were lower than the 4-point bending strengths. (2) From the S-N curve of ceramic/metal joints in this study, the fatigue limit was estimated to be approximately 280 MPa. (3) From SEM and EPMA observations, the first stage of fatigue fracture was caused at the Ti-rich layer existing next to the ceramic/braze layer interface.