Prediction of fatigue lifetime and fatigue limit of aluminum parts produced by PBF-LB/M using a statistical defect distribution

Fatigue tests were performed with samples of AlSi10Mg produced by PBF-LB/M. The failure is caused by inhomogeneities nearby or at the surface of the samples. Therefore, the fatigue strength depends on the crack growth behavior at inhomogeneities under the local stress state at the surface, including residual stresses. For a given size of the failure-causing inhomogeneity, the fatigue lifetime can be described using a crack growth law proposed by Murakami et al. The fatigue limit is given by the threshold value of fatigue crack growth according to the approach of El Haddad. Knowing the distribution of the maximum value of inhomogeneity size in a specimen, it is possible to estimate the S-N curve for 10%, 50%, and 90% crack probability.