The dynamic measurement model for the interface cavities of the diffusion welded joint, which based on the effective resistivity, is established by using the damage factor and the Derby Model of the Bridgman Law. Then the quantitative relationship, which between the direct current potential and the effective area of the joint at high temperature and high pressure, can be obtained. In addition, on the basis of the dynamic four-probe DC potential method and the fieldbus technology, the computer measuring system is established, so that the creep propagation behaviour for the interface cavities of the 316L stainless steel can be monitored in real-time.

The creep and rupture test were carried out on a non-standard specimen of 316L stainless steel (316L-SS) diffused bonding joint. And the θ-projection model was used to analyze the minimum creep strain rate and the remaining life at 500°C/6 MPa when the creep strain is 0.2%. According to the test results, design criterion for the diffusion bonding component at high temperature is established. The rupture experimental results show that the remaining life extrapolated by Larsen-Miller equation is relatively consistent with that calculated by the θ project concept method.