The effect of two-step aging treatment on the fatigue behavior of welded
AA 7020 Al. alloy was investigated. For fatigue tests to be carried out
in atmospheric and seawater environments, a plane bending tester at a
stress ratio of R=0 was used. Experiments in the control group were
carried out with non-welded specimens at a strain rate of R= -1 in air.
The gradual heat treatment (two step aging, TSA) significantly improved
the fatigue and corrosion fatigue behavior of welded AA 7020 alloys.
Unwelded specimens showed better fatigue properties than welded ones. In
experiments in a seawater environment, pitting and exfoliation corrosion
occurred on the surface. It was determined that the corrosion pits
reduce the fatigue life of welded and unwelded samples. It was also
observed that the corrosion sensitivity of the welded specimens
increased in the heat affected zone (HAZ) and corrosion fatigue cracking
occurred in these zones.