关键词: 断裂, 腐蚀坑, 腐蚀损伤, 铝合金, 疲劳

Abstract: The alternate experiment of corrosion and fatigue is performed for aviation LY12-CZ aluminum alloy specimen. Under the two kinds of action of “corrosion+fatigue” and “fatigue+corrosion+fatigue”, the effect on fatigue characteristic and fracture mechanics discrepancy of specimens are analyzed using the conditions of several temperatures and different durations. The discussion based on the testing results shows that the total fatigue lives of “fatigue+corrosion+fatigue” specimens are longer than “corrosion+fatigue” specimens under the same corrosion condition, and the increasing amplitude of fatigue life decreases with the increase of the initial fatigue life.The microcracks and intrusions/extrusions produced at the initial fatigue blunted by corrosion are the major reasons for increased fatigue life. It seems that a modest amount of corrosion actually has a beneficial effect on the material’s micro-damage and fatigue life by blunting of microcracks under the action of“fatigue+corrosion+fatigue”. The micro-damage of fatigue is removed and then substituted by corrosion pits when badly corrosion (for example, corrosion time 40 h, temperature 60 ℃). The effect on fatigue life if fatigue and corrosion are sequentially intermittent is indistinctive.

Key words: Aluminum alloy, Corrosion damage, Corrosion pit, Fatigue, Fracture