Combined effect of surface treatment and heat treatment on the fatigue properties of AISI 316L, manufactured by powder bed fusion of metals using a laser (PBF-LB/M)

This work deals with the combined influence of surface treatment and heat treatment of 316L manufactured by powder bed fusion of metals using a laser (PBF-LB/M/316L) on the fatigue behavior. Two surface treatment methods (manual polishing, vibratory grinding) were investigated. Fatigue testing of six different surface and heat treatment parameter setups was conducted. Metallurgical investigations such as etching patterns, density measurements, surface roughness measurements, fracture surface analysis with a scanning electron microscope (SEM), X-ray diffraction (XRD) and electron backscatter diffraction (EBSD) were performed. The mechanical properties were examined by tensile tests and fatigue tests. The influence of grain size on fatigue life was found to be the primary factor, followed by the surface roughness and subsequently the residual stresses on the surface ultimately contributing to the overall effect.