The Effect of Sensitization on the Stress Corrosion Cracking of Aluminum Alloy 5456

Download
Author
Cormack, Emily C.
Date
2012-06Advisor
Brewer, Luke N.
Second Reader
Farmer, Joseph C.
Metadata
Show full item recordAbstract
This work examines the effect of sensitization on the stress corrosion cracking behavior of marine grade aluminum alloys (Al-Mg). These alloys can be sensitized during operation, promoting their susceptibility to intergranular stress corrosion cracking (IGSCC). Aluminum alloy 5456-H116 (also identified as Al-Mg5.1) samples were sensitized at 175C for varying durations of time and then mechanically tested in salt water. Mass loss tests quantified the degree of sensitization (DOS) as a function of sensitization time. Dual cantilever beam tests were used to measure the SCC growth rate and cyclic fatigue tests were conducted to determine the corrosion fatigue behavior. DOS increased as sensitization time increased with little difference in mass losses above 336 hours. Stress corrosion crack growth rate increased as sensitization time increased. Although the sensitization rates for AA5456-H116 were higher than for AA5083, the stress corrosion crack growth rates were significantly lower. The stress corrosion fracture surfaces showed clear showed a clearly intergranular fracture path with extensive crack branching and delamination in the transverse direction.
Collections
Related items
Showing items related by title, author, creator and subject.
-
THE ROLE OF STRESS IN THE CORROSION CRACKING OF ALUMINUM ALLOYS
Scott, Brian E-S. (Monterey, California. Naval Postgraduate School, 2013-03);This work examines the effect of stress on the rate of sensitization, the rate of pitting corrosion and the rate of crack nucleation of aluminum alloy 5083-H116 aluminum. Stress corrosion cracking in aluminum superstructures ... -
The effects of applied stress and sensitization on the passive film stability of AL-MG alloys
Fleming, Jennifer S. (Monterey, California: Naval Postgraduate School, 2013-06);This thesis evaluates effects of stress on the corrosion behavior for the aluminum magnesium alloy AA5083 in a comprehensive and systematic manner. This study used cyclic polarization and electrochemical impedance spectroscopy ... -
Characterization of aluminum-magnesium alloy reverse sensitized via heat treatment
Gamble, Kevin D. (Monterey, California: Naval Postgraduate School, 2016-09);This research explores a novel repair technique to reverse the sensitization of aluminum magnesium (Al-Mg) alloys. Al-Mg alloys can become sensitized when magnesium comes out of solution as a second phase, Al₃Mg₂, on the ...