A detailed study of rapid stress corrosion cracking (SCC) in a 7075 aluminum alloy has allowed separation of the mechanical and chemical contributions. This was accomplished by combining scanning electron microscopy, stress wave emission, and crack growth rate observations as a function of testing temperature. The data obtained established an activation energy of 11. 2 kcal/mol, a stress intensity squared dependence of crack growth, and a range of 20 to 80% dimpled rupture on the fracture surfaces. Thus a two-step crack growth mechanism is proposed combining a thermally activated electrochemical process and a discontinuous mechanical jumping process.
|Original language||English (US)|
|Number of pages||10|
|State||Published - Jan 1 1974|