Multi-scale correlations between residual stress and microstructural features in additively manufactured 316L stainless steel

Additive manufacturing (AM) is one of the most rapidly developed fabricating techniques over last two decades. The microstructure feature or the residual stress distribution in AM components was widely investigated on its own. However, limited studies were attempted to reveal the correlations between the microstructure and residual stresses in AM components. In this study, high-energy synchrotron X-ray with the cross section of 0.5 mm × 0.5 mm was applied to determine the localized fluctuation in residual stress distribution for direct energy deposited 316L stainless steel thin plate with complementary microstructural investigation. The residual stress in macroscopic scale progressively varies with the changing bulk cooling rate, which was implied by the secondary dendrite arm lengths. The abrupt localized fluctuation of residual stress at meso-scale was revealed along with the corresponding variations in dendritic morphologies. Potential correlations between the meso-scale residual stresses and the microstructure morphologies were analyzed considering localized solidification conditions.