New light-weight materials for new technology applications

In order to meet the future EU challenges about light-weighting and pollution reduction, especially relevant in transportation sector, one of the biggest EU projects: ExoMet, was launched in 2012. The ExoMet project has successfully produced new light weighting aluminium and magnesium alloys with improved mechanical properties by exploring grain refining and nanoparticle additions in conjunction with novel melt treatment.

Manufacturing scale-up was tackled in the ExoMet project using a variety of techniques such as low and high-pressure die casting, sand casting, investment casting, differential-pressure casting, twin-roll casting, ultrasound-assisted casting and twin-shear casting. The novel application of external fields to these industrial techniques would bring major savings in energy, scrap and processing cost.

The ExoMet project is now in the 4th (last) year, where the prototype components are developed and tested by the industrial end-users participating in the project. Four commercial sectors were selected for the industrial applications: (i) automotive powertrain and chassis, (ii) aircraft and aero-engine structures, (iii) satellites and rockets and (iv) high-strength high-conductivity Al electrical cabling. Some major results achieved during the project are specified herewith.

1. Novel grain-refining master alloys
   Master alloys were developed by using new grain refiner compositions. The innovativeness of the new master alloys is to provide higher efficiency of grain refinement which means lower addition and/or enhanced product quality versus conventional TiB-based master alloys. The unique selling point of these new materials are the smaller intermetallic, better surface finishing and better toughness. These new alloys will provide better technical characteristics for the industrial applications. In that case, aluminium foundry industries will be the main market for these materials.
   
   
2. Contactless device for microstructure refinement and stirring of alloys
   Contactless device technology basically covers two parts which are; (i) grain refinement of light alloys by stirring / cavitation using a nonchemical, and (ii) dispersion of strengthening particles in light alloys using a non-contact method. Existing grain refining methods rely on ultrasonic treatment using a consumable immersed sonotrode, or alternatively on the addition of chemical refiners. In the first instance, the melt is contaminated and in the second one, undesirable agglomerates can be formed. The new technique requires no chemical additions, and because it is non-contact, it can avoid contamination. In addition, the technique combines acoustic vibration with bulk stirring and heating of the melt.
   
   
3. Prototypes
   The prototypes demonstrators will prove the ExoMet technology beyond the laboratory scale: The components are aluminium and magnesium based cast:
   
   • Satellite frame with AM60+nano particles
   • Electrical cabling with aluminium+nano particles
   • Seat frame with AM60+nanoparticles

Steinbeis R-Tech Role
R-Tech contributes to health & safety assessment, life cycle assessment and cost-benefit & supply chain analysis of selected light alloy/MMNC components. R-Tech also advised the coordination of the project in regards to the IPR (Intellectual Property Rights) activities.

In the context of Life Cycle Assessment, for a selected component (seat frame), environmental, health and resource related impact categories of aluminium alloy (AlSi10Mg) and steel were compared. The results of the analysis showed that aluminium alloy have a better environmental performance when compared with steel. The Environmental assessment was done by using the impact assessment method, ReCiPe. Concerning Cost-Benefit & Supply Chain Analysis, first of all, Net Present Value (NPV) of fuel was calculated for selected industrial components (seat frame and engine piston) which were produced with new alloys. Regarding the analyses, it was showed that the usage of the new materials can contribute some benefits in economical, technological, technical and environmental manner. Due to commercial sensitivity, the detailed technical reports will be largely kept confidential within the consortium. However the research developed within the ExoMet project was openly published in journals and conference proceedings in order to make the project results available to the broader scientific community. Also, a number of high-impact dissemination and education deliverables ensure good broadcasting of project results and standards into the public domain. In addition, the consortium will provide a publishable executive summary report and a “European Research Roadmap for Light Alloys and Liquid Metal Engineering” that will help steer future research in this area.

Thanks to the developments of grain refinement additions and new processes to achieve better master alloys, the ExoMet project has largely contributed to generate new technological applications which will help the European Industries to reach the targets of light-weighting and reduction of emissions.

Dr.-Ing. Aleksandar Jovanovic is director of the Steinbeis Advanced Risk Technologies Group in Stuttgart. The alliance of enterprises offers its customers a variety of services related to business risk management, the analysis and management of technical risk, data analysis, and project management. Flor Angela Quintero is a director of a center belonging to this group alliance and Gozde Kara is a research assistant at Steinbeis Advanced Risk Technologies.

Dr. Wim Sillekens is a manager working on the ExoMet project at the European Space Agency (ESA). 

Prof. Dr.-Ing. Aleksandar Jovanovic, Flor Angela Quintero, Gözde Kara
Steinbeis Advanced Risk Technologies GmbH (Stuttgart)
aleksandar.jovanovic@stw.de

Dr. Wim Sillekens
European Space Agency (ESA) (Paris)
Wim.Sillekens@esa.int