Analysis Of Mechanical Characteristics On Stress Corrosion Cracking Tip

Stress corrosion cracking (SCC) is a crack propagation behavior occurred at the crack tip(fracture process zone), which is effected by corrosion environment, materials and mechanicsproperties nearby crack tip. The oxide film rupture model is one of the mechanism models ofstress corrosion cracking (SCC)，which is generally accepted and used quantitatively toestimate the growth rate of stress corrosion cracking of the nickel-based alloys in hightemperature environments. The stress and strain at the tip of SCC crack in the key nuclearstructural material was discussed by using a contoured double cantilever beam (CDCB)specimen and combining by a numerical simulation and multi-scale method in thisdissertation.Main research works performed are as follows:(a) To maintain the stress intensity factor (KI) of specimen constant as the crackpropagating in a certain range, a contoured double cantilever beam (CDCB) specimen isadopted in this study. A macro global model of CDCB specimen and a micro sub-model offracture process zone with oxidation film at the tip of SCC are constructed by using finiteelement software ABAQUS;(b) The stress and strain at the tip of SCC is simulated and obtained respectively in theoxidation film, the base metal and the crack propagation direction as the crack propagating;(c) The effect of the yield stress or hardening exponent of base metal on the stress andstrain at the tip of SCC is simulated and obtained in the oxidation film, the base metal and thecrack propagation direction;(d) The effect of the yield stress or hardening exponent of oxide film on the stress andstrain at the tip of SCC is simulated and obtained in the oxidation film, the base metal and thecrack propagation direction.The results of this investigating provide a theoretical foundation for quantitative prediction of SCC growths rate of nickel-based alloy in the high temperature waterenvironments.