Fatigue behavior under variable amplitude loadings in AlSi10Mg alloy components produced by laser powder bed fusion

This study investigates the fatigue behavior of AlSi10Mg alloy manufactured via laser powder bed fusion under variable amplitude loading conditions. Two material conditions were examined: as-built and stress relief, with the later involving a lower temperature compared to the conventional heat treatments, aimed at preventing the Al-Si network rupture. Fatigue tests were conducted using two distinct loading spectra: block loading and random loading. While the stress relief reduced the monotonic properties of the material, it resulted in increased fatigue performance due to the homogenization of residual stress throughout the depth. Fracture surface analysis revealed initiation points on subsurface defects, with both block and random loading cases exhibiting overload markings from loading transitions. The predictive model incorporating crack initiation and propagation periods yielded good results, with the equivalent stress range approach providing higher quality estimation compared to the real stress range approach. Fatigue behavior under variable amplitude loadings of AlSi10Mg is investigated. Stress relief reduced the monotonic properties but enhanced fatigue resistance. Random spectrum exhibited higher fatigue performance due to lower mean stress influence. Crack initiation and propagation periods were predicted using a linear damage rule.