Investigation of the Influence of Laser Powder Bed Fusion (LPBF) Processing Parameters (Contour Scan) on Microstructural Properties and Resulting Crack Initiation Behaviour under Cyclic Loading for AISi7Mg0.6 Material

This study provides a comprehensive experimental assessment of how contour scan speed and pre-sintering influenc near-surface integrity and fatigue crack initiation behaviour in LPBF-fabricated AlSi7Mg0.6. As a first step, existing surface topography and fatigue data are re-analysed to identify critical surface parameters, finalise test stress levels and life targets, and define expected crack initiation locations; this pre-testing phase provides a quantitative reference for validating the new experiments. LPBF specimens with systematically varied contour scan conditions are then characterised by (i) metallographic cross-sections to reveal microstructure and melt pool evolution in the contour and transition zones, and (ii) X-ray diffraction to quantify the contour-dominated residual stress state as a function of scan speed and pre-sintering.