The Correlation of Fracture Mechanism and Behavior of Residual Stress in Ceramic/Metal Joints
Naoto SHIRAKI, Yoshihiro SUGIYAMA and Kimihisa MINO
Abstract:In order to clarify the correlation of the fracture mechanism and the behavior of the residual stress in the ceramic/metal joint, the residual stress was measured by X-ray diffraction method during applied bending stress. Sintered silicon nitride (Si3N4) and stainless steel (SUS304) were used as specimen materials. The stress analysis by finite element method (FEM) was carried out, and was compared with X-ray measurement results. The obtained results were as follows: (1) The measured stress was larger with the applied stress. (2) As the applied stress was larger, intensity of the stress singularity, K was larger and ăwhich shows the order of the stress singularity was smaller and then became constant. (3) The behavior of K and ăagreed in the experimental results and the analytical results qualitatively well. (4) At the low-loaded region, there was a difference for the behavior of K and ă depending on the shape and dimension of specimen. But, when the applied stress was larger, K and ă become constant respectively. (5) To observe the change of stress singularity at the interface, it is possible to estimate the stress of fracture initiation. Key Words:Ceramics, Active brazing method, Bonding residual stress, Interface Ceramic/metal joint, X-ray diffraction method, Finite element method (FEM)