Modeling of the ageing of metallic powders used in additive manufacturing – MOVENTER

The economic and environmental sustainability of powder-bed additive manufacturing processes of aluminum-based alloys will lie on the control of raw material all over the manufacturing steps: powder production, storage, transportation, use in additive manufacturing chamber, reuse, recycling and finally end-of-life. Among these steps, the ageing of metallic powders during storage may lead to the degradation of chemical and rheological properties of the powders, depending on storage conditions: namely humidity and temperature. Yet, the mechanisms and the kinetics of this ageing are not fully understood to this day. The M?VENT?R project will first address the different phenomena occurring during ageing by simulating in lab the storage conditions met in industry thanks to dedicated climate chambers. The degradations generated by this artificial ageing on the surface of grains will then be characterized chemically by X-Ray photoelectrons spectroscopy. The modifications of interaction forces between grains will also be probed by atomic force microscopy using cantilevers functionalized with aged grains. All these surface properties of aged grains will be connected to more macroscopic properties of a powder such as flowability. This experimental approach will then support the kinetics modeling of ageing of metallic grain powder, which in its turn will be correlated to a qualitative model of rheology properties of the powder. This project should bring elements to understanding the ageing of powder in order to prevent it. This knowledge as well as techniques and protocols developed here may be of interest to understand the other steps of the whole additive manufacturing process where powder may be degraded.