SFI PhysMet - Centre for sustainable and competitive metallurgical and manufacturing industry

An important aim of SFI PhysMet is to enable more use of recycled metal, e.g. by increasing the understanding of how alloying elements accumulated by recycling affect microstructure and properties. Boron is a common trace element in recycled cast iron with potentially harmful effects, and it is important to map out what those effects are. Even small amounts (ppm) are harmful. In 2023, the consequence of using up to 40% aluminium (Al) from incinerator bottom ash (IBA) in industry-relevant Al alloys has been studied both experimentally and numerically. The purpose is to understand the effect of increased values of trace elements on microstructure and properties. The microstructure is evaluated by the butanol method, microscopy and X-ray diffraction. The addition of IBA leads to a distinct change in the microstructure, and new phases (not previously described in the literature) have been observed. Mechanical properties such as yield and tensile strength are not greatly affected, but ductility is significantly reduced when the content of recycled aluminium is increased. Fracture surface analysis reveals a greater amount of oxide films in the material, indicating a need to treat the melt when IBA is used. Both for welding of aluminium and steel and these in combination, and for their application in large structures (e.g. bridges and off-shore wind mills), there is a need for improved and new welding methods, especially for welding thick materials. Steel sheets, 40-45 mm thick, are joined by two-sided laser-hybrid technology, and microstructure and mechanical properties are characterized. Methods for changing the microstructure of the weld root are initiated by means of preheating and the addition of welding material forming non-metallic inclusions. This enables a ductile microstructure with good toughness. For welding 15 mm steel plates with very high productivity, single-sided laser hybrid welding and joint geometry are developed to provide a stable welding process with minimum welding defects. Full-scale bridge sections produced with laser welding are tested for fatigue with very good lifetime results - at least as good as with traditional welding. Welding aluminium requires the development of high-strength Al welding wires with additives of alloying elements or nanoparticles, and we are studying the possibility of producing these by new innovative manufacturing processes. The microstructure of these welding wires is studied with TEM to understand material properties and pore formation. For the development of lighter battery systems, e.g., in cars, it is possible to replace copper with aluminium, so we are studying methods for using aluminium in these and joining aluminium and copper. Together with industry partners, we also develop solid-phase joining technology (HYB & friction welding) and study the properties of the joint. The SFI develops numerical tools for solidification and defect formation using thermodynamic databases suitable for studying the effect of contaminant elements from recycling. This supports two activities aimed at i) the use of Al from IBA as a source in Al10SiMg and ii) the effect of impurities in cast iron. In 2023, the solidification modelling framework has been used to support the experimental work on adding aluminum from IBA to Al foundry alloys. Preliminary results show good agreement between calculations and experiments. In addition, models for heat crack sensitivity have been further developed to include more alloy-specific properties. Implementation of multi-object optimization has also begun; Numerical algorithms that can be used to design new alloys based on a set of specifications for chemistry, process or properties. Activities targeting additive manufacturing (AM) include process development for the production of Al-6xxx alloys and include a study of the effect of SiC nanoparticles on microstructure and cracking. In 2023, models have also been developed for the microstructure of Al alloys produced by AM. Furthermore, work is conducted to establish an automatic workflow for calculating the basic thermodynamic parameters of crystals and solution atoms in alloys at finite temperatures. Such data is needed to generate phase diagrams and as input parameters for microstructure models. The existing SFI PhysMet web portal has been updated and expanded with a database of available models and web apps for microstructure models. A new data catalog based on DataVerse has also been created and populated with TEM data and stress-strain curves. Also work on how data can best be documented so that it can easily be reused and understood by both machines and humans have been done, as well as a pilot on how the Centre connects to and utilizes SINTEF's upcoming data management system called data.sintef.no. The recommendations and methodology for traceable data documentation and efficient workflows have, together with Raufoss Technology, been tested on production data for damper for

Centre for Sustainable and Competitive Metallurgical and Manufacturing Industry (SFI PhysMet), hosted by NTNU, together with key research partners (SINTEF, IFE), user partners from the metal based industry in Norway (Hydro, Elkem, Benteler, Raufoss Technology), end users (Equinor, Norwegian Public Roads Administration (NPRA)) and an international partner (ThermoCalc (S); making thermodynamical software) constitute a Centre for Research-based Innovation. The objective of SFI PhysMet is to enable and accelerate the transformation of the national metal industry towards more sustainable and cost-efficient production, future material products, solutions and improved processing methods. SFI PhysMet will contribute to long-term competence building and prepare for innovations through (i) Education and training of PhD-candidates, postdocs and master students with a good combination of fundamental physical metallurgy competence and digital skills; (ii) Development of a PhysMet Innovation Platform, providing efficient and flexible access to through process and through scale workflows combining advanced scientific models, experimental data and expertise to support the industry in accelerated innovation; (iii) Development of cutting-edge expertise, contributing to national competence building within four main areas i) metal recycling and compensational metallurgy, i.e. the ability to cancel negative effects of impurities and exploiting potential positive effects of impurities and increased amounts of alloying elements, enabling significantly more recycling in the metal-based value chains; ii) solid-state recycling (e.g. screw extrusion) and mechanical alloying, with the prospect of new alloys and composites with improved properties; iii) rapid solidification, with prospects of development new feedstock materials for additive manufacturing; and iv) welding and joining methods, with prospects of new material- and processing solutions for high-end markets.