Crack initiation behavior and fatigue performance up to very-high-cycle regime of AlSi10Mg fabricated by selective laser melting with two powder sizes

The high-cycle and very-high-cycle fatigue (VHCF) behavior of AlSi10Mg specimens manufactured by selective laser melting with different printing powder sizes was investigated. The specimens with 20 μm powder size contained more defects than those with 50 μm powder size, and the latter have a higher fatigue property than the former. Unmelted powders were detected as the main source of crack initiation. The specimens printed with 50 μm powder size are more likely to feature subsurface crack initiation in the VHCF regime. Five different types of crack initiation modes were identified, and the fatigue strength was assessed by statistical model.