Materials, and here especially metals and alloys, are energy- and thereby carbon-intensive to produce. The primary production of steel and aluminium alone, are accounting for a share of roughly 13 % of global CO₂ emissions. The circular use of materials therefore is critical to reach important climate targets. In theory, metals should in principle be infinitely recyclable without fundamental property loss. This would mean that better alloy design, scrap sorting, and secondary metallurgy can dramatically close material loops and reduce demand for virgin ore. In reality however, certain elements will enrich in the alloys with each reuse cycle, possibly degrading the properties to a point where the materials can no longer be employed. Alloying elements might also be either environmentally critical, or have to be sourced from regions where supply chains might be easily disrupted. Combined, this means that there is a critical demand for sustainable materials in mechanical engineering.

• What is sustainability and what are the so-called R strategies?
• Structure–property–processing relationships for sustainability: How microstructure, bonding, and processing routes determine recyclability, degradability, and the embodied energy
• Material degradation and durability – corrosion, fatigue, polymer aging, and how extending service life might reduce material throughput
• Bio-based and biodegradable materials – cellulose, lignin, PLA and other bioplastics, biocomposites; their mechanical performance vs. conventional materials
• Metals and alloys: secondary (scrap-based) metallurgy, alloy design for recyclability, substitution of critical/conflict materials
• How can we overcome less suitable material chemistry due to circular usage with microstructure design
• This will be discussed for steels, aluminium alloys and other important alloy classes
• Novel and emerging sustainable materials
• Characterization and testing methods

The students

• learn how sustainability is defined, especially in the context of materials engineering
• understand which general challenges arise when materials are used in a circular fashion
• know how these challenges affect different materials classes
• understand circularity concepts for polymers, ceramics and metallic alloys
• know what the main challenges and mitigation strategies are for steels
• know what the main challenges and mitigation strategies are for aluminum alloys
• know what the main challenges and mitigation strategies are for other important alloys, e.g. titanium systems
• understand what solutions nature has found for the circular and energy efficient use of materials

Basic knowledge in materials science (e.g. lecture Materials Science and Engineering I and II) recommended

regular attendance: 22,5 hours

self-study: 97,5 hours

Success is assessed in the form of an approx. 30-minute oral examination.

no tools or reference materials