EFFECT OF THE POST WELD HEAT TREATMENTS ON THE FATIGUE CRACK GROWTH BEHAVIOR IN FRICTION STIR WELDING OF A HEATTREATABLE ALUMINUM ALLOY

Tran Hung Tra

Abstract: The effect of the post weld heat treatments (PWHTs) on the fatigue crack growth (FCG) behavior in the welded zone of AA6063- T5 fabricated by the friction stir process was investigated. The FCG specimens are machined in which the loading axis is put perpendicular to the welding line and the initial notches are introduced in the welded zone. The experimental results showed the FCG rates are sensitive to the PWHT solutions. The FCG resistance in the welded zone could be fully restored to that of base metal by using PWHT. While the PWHT solution solely restores the precipitates dissolved and/or coarsened during welding process has a minor effect on the FCG rates, the PWHT solution remarkably recrystallizes the grain microstructure has a significant effect here.

Keywords: Aluminum alloy, Failure assessment, Fatigue crack propagation, Friction stir welding

DOI: https://doi.org/10.15623/ijret.2015.0403002