Effect of notches on the deformation behavior and damage evolution of additively manufactured 316L specimens under uniaxial quasi-static and cyclic loading

Powder bed based additive manufacturing techniques enable for fabrication of filigree and geometrically complex structures. These structures typically are characterized by many cross section transitions, leading to notch induced stress concentration. Furthermore, the process induced surface roughness cannot be always mechanically removed as the surfaces are not accessible using conventional tools. Although these factors are critical for many different applications and materials, previous works mainly focused on notch effects in brittle materials, such as the common Ti-6Al-4V alloy. Systematic examination of notch induced stresses in ductile materials, especially under the constraints of process induced surface roughness and small part dimensions, was not conducted. Thus, the present study addresses these issues by evaluation of the mechanical performance of notched samples made of 316L stainless steel under quasi-static and cyclic loading. By means of digital image correlation insights into the local deformation mechanisms and the damage evolution, respectively, were obtained. Microstructural analysis by electron backscatter diffraction provided profound explanation for the phenomena observed.