Corrosion behavior and stress corrosion cracking resistance of Al-Li alloys.

Three type Al-Li alloys (8090, 8091 and 2090) sheets were aged at 443K in various temper conditions, and evaluated for corrosion behavior and resistance to stress corrosion cracking (SCC) initiation in sodium chloride solution. The underaged alloys were susceptible to intersubgranular corrosion, apt to lead localized corrosion pits. The peak-aged alloys suffered from dimple type pitting, on alloy 8090 and alloy 8091 preferentially along subgrain and grain boundaries, and on alloy 2090 within grains also. The resistance to SCC initiation was in agreement with that to localized corrosion owing to intersubgranular corrosion, improved with increasing aging time, and ranked in the order of alloy 8090>alloy 2090>alloy 8091.