Unveiling damage sites and fracture path in laser powder bed fusion AlSi10Mg: Comparison between horizontal and vertical loading directions

The laser powder bed fusion (LPBF) additively manufactured AlSi10Mg alloy has been subjected to numerous investigations addressing its microstructure and mechanical properties. However, there is still a gap in the understanding of the correlation between the microstructure and fracture behavior, in particular when the melt pool border is oriented differently to tensile load. In this work, damage nucleation sites and fracture path of as built LPBF AlSi10Mg were analyzed and compared for two loading directions. For the first time, the orientation of the melt pool border is shown to present negligible effect on a ductility exceeding 10%, in contrast to previous works. Through observation and statistical analysis of damage, it is found for both loading directions that the melt pool border does not exhibit damage localization. When the melt pool border is perpendicular to tensile load, the crack propagates frequently along the coarse melt pool due to easier damage growth in this relatively softer region. Nevertheless, the ductility is barely compromised owing to delayed damage coalescence across larger alpha-Al cells.

Automated summary

The study found that the orientation of the melt pool border has negligible effect on the ductility of LPBF AlSi10Mg alloy, contrary to previous research. Regardless of the loading direction, the melt pool border does not lead to damage localization, with cracks propagating along the pool without compromising ductility.