Integrated development and qualification of high-strength aluminum alloys using laser powder bed fusion

• Applicant: Dr.-Ing. Uta Kühn
• Subject Area: Mechanical Properties of Metallic Materials and their Microstructural Origins ; Primary Shaping and Reshaping Technology, Additive Manufacturing
• Term: since 2020
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 437911652

Additively manufactured Al-alloys offer an excellent suitability for lightweight construction through a suitable component design and due to their high specific strength. Currently, their processability is still very challenging. For this reason, this project aims to develop a new high strength Al-alloy for powder based additive manufacturing. The starting point is provided by the Al92Mn6Ce2-alloy, which was manufactured by LPBF (laser powder bed fusion) and comprehensively characterized in the period of the first proposal. The formation of the metastable, high-strength Al20Mn2Ce-phase in combination with the ductile Al-matrix led to outstanding compressive strength and ductility, as well as a high hardness. The aim of the renewal proposal is to create an alloy, which exceeds the achieved mechanical properties and the processability by LPBF. The intended alloy development is based on casting while maintaining high cooling rates. This enables the modification of the alloy through an addition of silicon and zirconium in a material- and time-efficient way. The chemical composition will be chosen with regard to the structure-property-relationship as well as to the suitability for LPBF (e.g. through measurements of the melt viscosity). In the second step, the chosen composition will be assessed after the actual manufacturing by LPBF. The evaluation of the cast and LPBF as-prepared samples provides new insights about the effect of the alloying elements onto the phase formation. Thus, the relation between chemical and microstructural impacts will be connected to the LPBF-process and the mechanical properties. Both degrees of freedom, the composition as well as the process parameters (LPBF and heat treatment), allow the specific adjustment of the microstructure and consequently tailored mechanical properties for applications in lightweight-construction.

• DFG Programme: Research Grants