Stress corrosion cracking of Al-Mg-Zn-Cu alloys after precompression

摘要: Stress corrosion cracking (SCC) experiments have been carried out on double-cantilever-beam (DCB) specimens of 7017-T651 aluminium alloy. The were first subjected to a known compressive load which caused plastic deformation at the notch tip. On unloading, this region developed residual tensile stress field and subsequent exposure moist air 40° C (95% relative humidity, r.h.), intergranular cracks formed. These grew decelerating rate until they stopped. final crack length increased with value initial preload, provided was below for general yielding Electron fractography has used correlate changes in surface morphology growth rate. It found that ductile tearing tip may occur during unloading when compression exceeds — 30kN. practical importance these results is outlined.