Effect of Film-Induced Stress on Mechanical Properties at Stress Corrosion Cracking Tip

Oxide film rupture theory has become one of the most popular models to quantitatively predict the stress corrosion cracking (SCC) rate at crack tip of nickel-based alloys in high temperature and high pressure environments, and stress intensity factor has become an important parameter to measure the stress corrosion cracking rate. In order to further understand the fracture mechanism of the oxide film and the driving force of crack growth, film-induced stress intensity factor was proposed. To understand the effect of film-induced stress intensity factor on the micro-mechanical state at the tip of EAC (environmentally assisted cracking), the stress-strain in the base metal at the EAC tip was simulated and discussed using a commercial finite element analysis code. And then the effect of film-induced stress intensity factor on Mises stress, equivalent plastic strain, tensile stress, tensile strain and tensile plastic strain gradient of crack tip was obtained, which provides a parameter to improve the quantitative predication accuracy of EAC growth rate of nickel-based alloys and austenitic stainless steels in the important structures of nuclear power plants. Therefore the oxide film rupture theory was improved.