Fatigue behaviour of selective laser melting steel components

The results showed that a very high scan speed (400 or 600 mm/s) causes the appearance of high percentages of porosity and a consequent drastic reduction of tensile strength and stiffness. Fatigue behaviour was assessed in terms of the traditional S-N curves and of the da/dN-ΔK crack propagation curves. Fatigue life predictions based on Hartman and Schijve's equation underestimated significantly fatigue lives, particularly for low stress levels. The results of the tests performed at variable amplitude loading were well fitted by Miner's law.