The influence of laser surface treatment on the fatigue crack growth of AA 2024-T3 aluminum alloy alclad sheet

The purpose of this work is to study the effect of local heating using the laser heating process as a surface treatment to retard the crack propagation of an aluminum alloy. The heating process was applied over an aerospace grade aluminum alloy AA2024-T3 alclad sheet with 1.6 mm thickness. One and two heating lines were applied by a defocused Yb:fiber laser beam that generated a laser spot diameter of 2 mm, with laser speeds between 1 and 50 mm/s. For crack propagation tests, modified C(T) specimens were manufactured and tested according to ASTM E647. A layer of carbon black was applied over the surface of some specimens previously to the laser heating process. The obtained results shown that the fatigue crack growth was reduced using specific parameters for the laser heating process.