On the Influence of Cross-Section Size on Measured Strength of SLM-Produced AlSi10Mg-Alloy

Abstract

The freedom in choice of geometries in additive manufacturing (AM) favors the use of structures with large surface and small cross-section such as lattice structures and thin-walled hollow profiles. On the other hand, the practices of strength testing of metals require a certain bulk of the material to be printed to be able to produce a sample and test material properties. The size of the sample cross section might influence the strength and up to 30% decrease in strength for small struts was reported in the literature. Understanding the influence of the cross-section size on the strength of SLM-produced metal is crucial to be able to relate the strength determined through tensile testing and the strength of an SLM-produced component with complex geometry. This article deals with effect of cross-section size on the measured strength of the SLM-produced AlSi10Mg-alloy. It is demonstrated how the decrease in strength can be explained by the difference between measured and actual cross-section area induced by surface roughness rather than by the difference in microstructure between the samples of different sizes.