Workshop Details:
Date: October 13 (13:00-17:00) and October 14 (9:00-17:00) 2025
Location: Building: SuperC – RWTH Hochschulverwaltung, room “Generali Saal” (top floor of the building)
RWTH Aachen Link: https://www.rwth-aachen.de/cms/root/wir/kontakt-anreise/raumverwaltung/~tld/superc/
Google Maps Link: https://maps.app.goo.gl/yj2KUGefyStcdYUr8
Abstract:
Nearly four years have passed since the publication of the review article “Making sustainable aluminum by recycling scrap: The science of “dirty” alloys”. In that time, both industry and academia have made progress toward reducing the environmental impact of aluminum, yet major challenges remain. Primary production continues to carry significant carbon costs, while increasing volumes of post-consumer scrap present new metallurgical complexities. This workshop will bring together researchers and industry partners to revisit these issues, with a particular focus on how physical metallurgy can guide the design of alloys and processes that tolerate impurities and enable greater use of recycled material. By integrating perspectives from research and practice, we aim to chart pathways for lowering the footprint of aluminum alloys across their lifecycle.
| Monday October 13 Arrival: 13h00 – 13h30 | |||
| 13h30 | Welcome | ||
| 13h50 | T1: Chad Sinclair | Univ. of British Columbia | Motivation for Workshop: Aluminum’s Contributions to a warming world – what are the open questions? |
| 14h20 | T2: Jürgen Hirsch | Aluminium Consulting | Recycling and reducing CO2-emission of Aluminum processing |
| 14h50 | T3: Waleed Mohammed | MPI Sustainable Materials | Recycling and Upcycling Opportunities of Al Scrap |
| 15h20 | BREAK | ||
| 15h50 | T4: Katrin Bugelnig | DLR Köln | Combined high-throughput and experimental screening of printable Al alloys from scraps |
| 16h20 | Discussion | ||
| 17h00 | Wrap-up and Organisation of Possible Joint Evening (self-paid) | ||
| Tuesday October 14 | |||
| 9h00 | Arrival | ||
| 9h15 | T5: Dierk Raabe | MPI Sustainable Materials | Co-reduction mechanisms in mixed oxide metallurgy |
| 9h45 | T6: Joseph Robson | Manchester Univ. | Understanding the role of constituent particles on deformation and failure of recycled 6xxx alloy |
| 10h15 | BREAK | ||
| 10h45 | T7: Stefan Pogatscher | Univ. of Leoben | Aluminium-alloy upcycling from end-of life vehicles |
| 11h15 | T8: Michel Perez | INSA Lyon | Progresses in material sciences, lightweighting of vehicles and increase in CO2 emissions of transportation |
| 11h45 | LUNCH BREAK | ||
| 13h15 | T9: Lola Lilensten | Chimie ParisTech | Solid-state recycling of an aluminum alloy: process, recycled materials properties and paths for improvement |
| 13h45 | T10: Fanny Mas | Constellium R&D France | Constellium’s R&D initiatives for low CO2 aluminium |
| 14h15 | BREAK | ||
| 14h45 | T12: Eric Breitbarth | DLR Köln | Transforming Mechanical Test Labs into Autonomous Knowledge Discovery Hubs |
| 15h15 | Ending Discussion | ||
Talk Abstracts:
Motivation for Workshop: Aluminum’s Contributions to a warming world – what are the open questions? C. W. Sinclair, University of British Columbia
Aluminum, like all engineering materials plays a role in contributing to greenhouse gas emissions and thus global warming. These impacts span across the lifecycle of aluminum – from raw material extraction, to aluminum production, to product fabrication to end of life. The aim of this introductory talk will be to set the stage for the workshop, reflecting on the challenges, for academic researchers, of aligning our research goals with sustainable development goals. As part of this we will introduce the workshop speakers and set out the objectives for the 1.5 days.
Recycling and reducing CO2-emission of Aluminum processing J. Hirsch
The aluminum industry is evolving in response to the need for greater energy and material efficiency to reduce carbon intensity. The role and potential of aluminium for environmental protection are discussed and the importance of upgrading recycling of aluminium for a zero-carbon society are analyzed. Conventional production methods are increasingly constrained by high energy demand and process complexity. Modern continuous casting processes can contribute to improving the circular metallurgy by facilitating more efficient use of recycled material and overall process integration.
This contribution presents an expanded alloy classification framework combined with tailored recycling and upcycling strategies. The focus is on material streams with elevated impurity levels and advanced material flow from recycled ingots to the wrought aluminium products is discussed. Promotion of “upgrade recycling” together with the current horizontal and cascade (down-) recycling is a key to construct a complete aluminium recycling system in the future. New alloy systems and processing routes with high solidification rate casting can promote uniform microstructure and allow for further processing without segregation issues. By stabilizing high scrap content inputs and increasing tolerance to residual elements, continuous casting supports the development of new alloy families, including uni alloys and crossover alloys suitable for a wide range of applications.
The integrated approach, combining casting innovation, alloy design, and efficient scrap utilization, reinforces the principles of circular metallurgy provides a practical path to reduce reliance on conventional upstream inputs, broadening the use of recycled aluminum, and restore competitive manufacturing capability in strategic downstream applications.
Recycling and Upcycling Opportunities of Al Scrap W. Mohammed
We present the ongoing research on Al recycling and upcycling at the Max Planck Institute for Sustainable Materials. We highlight multiple pathways that are currently under investigation, including upcycling of cast Al scrap, recycling of 5xxx Al alloys, recovery of Al from batteries, and impurity removal from mixed scrap via melt-purification processes. We also showcase our inverse-design framework that leverages machine learning to tailor the properties of upcycled alloys. Together, these approaches outline potential routes that enable higher-value circular use.
Combined high-throughput and experimental screening of printable Al alloys from scraps K. Bugelnig
To achieve goals like climate neutrality by 2050 and a circular economy, material discovery must accelerate, especially as raw material costs and supply chain issues rise. Computational screening, advanced characterization, and machine learning enable this progress. A new Al-based alloy for additive manufacturing (AM) was developed from scrap metal mixtures using high-throughput screening and synchrotron-based validation. Designed for aerospace, it meets requirements such as low hot-cracking sensitivity, short solidification intervals, and suitable strength and ductility. Computationally, ~10,000 alloy compositions were generated by varying scrap ratios. CALPHAD simulations assessed phases, solidification, and mechanical properties, while a random forest model and multi-objective evolutionary algorithm identified optimal alloys. Uncertainty analyses accounted for scrap variability. Experimentally, candidate alloys were cast, remelted, and tested under different solidification rates. Synchrotron tomography provided 3D microstructural insights. A promising composition was processed into powder, and in-situ laser powder bed fusion with microtomography confirmed its AM suitability.
Co-reduction mechanisms in mixed oxide metallurgy D. Raabe
Traditional metallurgy is defined by a sequential, energy-intensive paradigm: the extraction of metals from their oxide ores, followed by alloying via liquid-state processing, and finally thermomechanical treatment to achieve target microstructures. This centuries-old approach is increasingly incompatible with the demands of a sustainable economy, as its reliance on fossil-derived reductants and high-temperature processing contributes significantly to global greenhouse gas emissions.
We present a fundamental shift in alloy synthesis: a solid-state process that utilizes H₂ to simultaneously reduce, alloy, and densify mixed oxide precursors. This method effectively merges the classical disciplines of extractive and physical metallurgy into a single, integrated operation. The approach is underpinned by a generalized thermodynamic framework and a kinetic model that describes the competitive reduction and interdiffusion pathways critical for forming homogeneous alloys from oxides.
This versatile synthesis strategy is applicable to a wide range of multi-component oxide systems, enabling the direct and sustainable production of bulk alloys. The process operates at temperatures significantly below the melting point of the constituent metals, circumventing the energy penalty of liquid-phase processing and enabling microstructural control in the solid state. We demonstrate its efficacy by producing high-performance, complex bulk and nanostructured alloys. The foundational science provides a pathway to decarbonize the production of numerous alloy families, unlocking new possibilities for sustainable materials design with a minimal CO₂ footprint.
Understanding the role of constituent particles on deformation and failure of recycled 6xxx alloy J. Robson
6xxx aluminium alloys contain coarse constituent particles formed from impurities such as Fe. These particles play an important role in deformation and failure. In this study, the behaviour of AA6111 produced from primary aluminium and a post-consumer scrap source have been compared. The distribution and characteristics of the constituent particles have been quantified in material from both sources. In-situ X-ray tomography during tensile testing has been used to explore particle cracking, void formation, and failure. High resolution digital image correlation (HRDIC) and complementary crystal plasticity/phase field fracture modelling has been used to study local behaviour around constituent particles. The effects of particle location, shape, orientation, and distribution have been determined and used to rationalise the different mechanical behaviour of the primary and recycled materials. This suggests design principles for recycling tolerant 6xxx aluminium alloys
Aluminium-alloy upcycling from end-of life vehicles S. Pogatscher
The shift to a circular economy depends on sustainable recycling of end-of-life vehicles. Aluminium parts in modern cars, including incompatible wrought and cast alloys, pose significant recyclability challenges. This incompatibility prevents reintegration of aluminium scrap, forfeiting energy, emissions, and cost savings. Electrification and material choices lead to a surplus of low-grade scrap, increasing the urgency for innovative recycling methods. This study introduces a process to upcycle mixed ELV scrap into high-performance aluminium alloys without sorting or dilution, compatible with existing infrastructure. Leveraging metallurgical principles, it achieves yield strengths surpassing commercial automotive alloys. The approach addresses current and future scrap compositions, offering a low-emissions, circular solution for aluminium recovery.
Progresses in material sciences, lightweighting of vehicles and increase in CO2 emissions of transportation M. Perez
An overwhelming mass of material science papers dealing with lightweighting materials justify their research topic invoking an obvious connection between weight of structural materials and reductions in CO2 emission in transportation. In this paper, we demonstrate that this connection is obviously largely untrue for car and quite inaccurate for areal transportation. For air traffic, due to a rebound effect, weight loss lead to a drop in plain ticket and an increase in demand. Thanks to the concept of price elasticity of demand, a relation is proposed between the weight loss of planes and the CO2 emission reduction. Progresses in material science lead to global CO2 emission reduction, but approx. 40% of these progresses are lost due to rebound effect.
Solid-state recycling of an aluminum alloy: process, recycled materials properties and paths for improvement L. Lilensten
Classical recycling processes for aluminum alloys include a remelting step of the collected scraps, whether new scrap (from production steps) or old scraps (end-of-life products) are considered. A new approach has been proposed, consisting in the scraps’ direct extrusion. This allows to bypass the remelting step, hence decreasing the energy required for recycling: producing primary Al consumes between 168 and 200 GJ/t, which goes down to 16 to 19 GJ/t for secondary Al production by remelting, when the new solid-state recycling approach divides this number by three, down to 5-6 GJ/t. This new process is thus very promising in the global warming context, where energy and CO2 emissions savings are sought. It could be applied first to new scrap, whose composition is clearly identified.
This process was implemented for the AA6060. Extrudates based on AA6060 chips were produced, and compared with extrudates based on AA6060 cast material, taken as a reference. This presentation will provide an in-depth analysis of the extrudates, with microstructural characterizations (SEM, TEM) and mechanical testing (tensile tests, damage analysis by in situ X ray tomography, shear tests). Mostly, we revealed that in spite of a Mg-concentration as low as 0.4%, MgO oxides, mainly, form on the chips surface during the process, leading to the formation of a mesoscale network in the final material. We investigated to what extent does it impact the materials mechanical performance, and how can we limit it through process optimization, based on an ex-situ study of the alloy oxidation.
Constellium’s R&D initiatives for low CO2 aluminium F. Mas
Decarbonization is the major challenge that aluminium industry is facing. That is why it is the focus of much of Constellium’s R&D efforts with several specific projects for each markets (aerospace, automotive, packaging…). From the R&D point of view of an aluminium remelter, it relies on several pillars:
- Decarbonizing the melting process and energy sources
- Increasing the impurity tolerance of existing alloys
- Building new scrap streams and associated sorting steps to recover high-quality EoL wrought aluminium
- Developing new grades based on abundant scrap sources
Examples of several Constellium’s initiatives will be shared with a special focus on scientific knowledge gaps to foster discussion within the research community.
Transforming Mechanical Test Labs into Autonomous Knowledge Discovery Hubs E. Breitbarth
The integration of machine learning, large language models, intelligent robotics, quantum computing, and advanced data acquisition is transforming traditional mechanical test labs into autonomous hubs for knowledge discovery. As we face pressing challenges like climate change and resource scarcity, leveraging these technologies in laboratory settings becomes essential for faster and more insightful scientific progress.
This talk will explore an automated, data-driven approach to knowledge discovery through fatigue crack growth experiments. In this setup, intelligent robotic systems continuously track the crack tip of a fatigue crack, capturing high-resolution digital image correlation (DIC) data. A machine learning model then processes these datasets to automatically detect and assess crack tip positions and associated crack tip loadings. Feature extraction is enhanced by a combination of classical algorithms and artificial intelligence, creating a rich dataset of analyzed results like the evolution of the plastic zone or the fracture surface characteristics.
To ensure the coherence and interoperability of diverse data sources, graph databases embedded with ontologies, semantics, and provenance data are employed. This structured approach enables the automated recognition of cause-and-effect relationships, consolidating knowledge within a unified knowledge graph. By streamlining data capture, analysis, and integration, autonomous labs hold the potential to significantly shorten development cycles, accelerating the path to market for new materials and products.
This paradigm shift from manual testing to autonomous knowledge discovery not only advances the scientific method but also strengthens our capacity to address complex, global challenges with speed and precision.