Ignition and explosibility of aluminium alloys used in Additive Layer Manufacturing

The ALM process (Additive Layer Manufacturing) uses metallic alloy powders with an average diameter in the range of 10-30 μm. This study concerns the characterization of an Al Si 10 Mg aluminium alloy spherical powder with a d50 of 17 μm and an oxide amount of 7-8 wt%. The MIE, Pmax and Kst are respectively 11-14 mJ, 8.5 bara and 165 bar m/s. The particle temperature measurement shows two levels of temperature: 3050 K during the first steps of the combustion and the second of 2550 K which occurs a short time after the Kst time. Finally, ignition delays are almost constant on a large range of dust concentrations and are at the same level as hydrocarbons.