セラミックス／金属接合体の破壊機構と残留応力挙動の相関性

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 λ which shows the order of the stress singularity was smaller and then became constant. (3) The behavior of K and λ agreed 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 λ depending on the shape and dimension of specimen. But, when the applied stress was larger, K and λ become constant respectively. (5) To observe the change of stress singularity at the interface, it is possible to estimate the stress of fracture initiation.