Effect of Distance along the Built Axis on Mechanical Properties and Microstructure in Al10SiMg SLM Alloy

Abstract

It is know that rapid solidification promotes solid solubility larger than at equilibrium, in association with very fine grains and eutectic microstructures. Consequently, the precipitation behaviour in additive manufacturing alloys can be quite different from that of alloys quenched after a solution treatment and aged. In this study, Al10SiMg samples were produced by Selective Laser Melting (SLM) while keeping the table at 150°C continuously during the job. The effect of temperature on mechanical properties of the samples was investigated as function of time or distance along the built axis (300 mm). The hardness behaviour was measured by micro Vickers indentations and significant inhomogeneities were detected along the built axes. These results were also confirmed by tensile property values. The tensile strength varied of 80 MPa from the bottom to the top of the sample. The microstructure was investigated by optical and scanning electron microscopy; the observations showed variable precipitate distributions that justify the mechanical response along the built axis.