Mechanical properties of Mn added Al-10%Si-0.7%Mg system alloys fabricated by selective laser melting

The mechanical properties of Al-10%Si-Mg system alloys containing Mn up to 1.5% fabricated by selective laser melting (SLM) with preheat temperature of 160°Cor 200°Cfor 15hours were studied by means of tensile test, hardness measurement and DSC analysis. The strength of the Mn added alloys was about 100 to 150MPa higher than that of the Mn free alloy. The bottom of the 1.5%Mn added alloy showed about 500MPa and 400MPa under preheat condition of 160°C and 200°C, respectively. Many compounds containing Si with size of about 40nm were observed at the bottom of the 1.5%Mn added alloy with preheat temperature of 200°C by STEM-BF image. Mn enriched zone was observed at eutectic (α-Al, Si) area of the 1.5%Mn added alloy by STEM-EDS. It is possible that Mn enriched zone directly or indirectly causes the high strength.