Behavior of Coarse Precipitates in the Aluminum Alloy AA 6013 T6 when Under a Cyclic Load in a Corrosive Medium

摘要

The aluminum alloy AA 6013 T6 is an alternative material for use in the fuselage and wing regions in aircraft construction. Commercial aluminum alloys contain coarse intermetallic compounds which are formed while the aluminum alloys solidify, and substantially ride out the processes of manufacture up to the production of sheet metal. Being inclusions in the material, they significantly influence the recrystallzation and fracture behavior of an alloy. These particles, when cyclically loaded in a corrosive medium, will undergo changes along the fatigue crack, that prove to be dependent on the testing frequency applied. The samples cyclically loaded by the laboratory air and in a corrosive medium, when anodically etched with a 3.5 percent NaCl solution, present a different etching result in the region of the crack tip, which can give an indication on that hydrogen is trapped in these particles or their interfaces.