Data: Fatigue crack growth behavior in an aluminum alloy Al–Mg–0.3Sc produced by wire based directed energy deposition process

 Additive manufacturing (AM) of Al-Mg-Sc alloys has received considerable interest from the aerospace industry owing to their high specific strength and suitability for AM. Since damage tolerance is a mandatory requirement for safety critical aerospace structures, this study has investigated the fatigue crack growth behaviour in an Al-Mg-0.3Sc alloy made by the wire and arc additive manufacturing. Tests were conducted with two different crack orientations at load ratios 0.1 and 0.5. At the lower load ratio and lower stress intensity factor range (<10 MPa m1/2), crack growth rate was 50% lower when it propagated perpendicular to the material build direction owing to larger grains along the crack path that caused more resistance to crack growth. When the crack grew parallel with the build direction, the crack tip encountered both smaller and larger grain zones, periodically; smaller grains gave much lower resistance to crack growth. When higher stress intensity factor range exceeded>10 MPa m1/2, isotropic crack growth rate property was measured; grain size effect was overcome by the mechanical factor (the stress intensity factor). At the higher load ratio 0.5, both the threshold and the critical values of the stress intensity factor range were reduced. Finally, the modified Hartman-Schijve equation was successfully employed to represent the crack growth rates including the threshold and the fast crack growth regions.