Fraunhofer Institute for Mechanics of Materials IWM
Challenges in materials technology that we tackle with our in-depth understanding of mechanisms, multiscale simulations and atomistic calculations:
- Hydrogen embrittlement: Hydrogen can penetrate steel (e.g. through electrochemical processes, weld seams or contact with H₂ gas). In steel, hydrogen accumulates at defects or grain boundaries, which can drastically reduce ductility and toughness and lead to brittle fracture. Protective coatings, alloying elements, and microstructural barriers must be developed to prevent hydrogen diffusion.
- Microstructure design: Microstructures (e.g., martensite, bainite, austenite) have different sensitivities to hydrogen and corrosion. Often, properties that promote corrosion resistance are detrimental to hydrogen resistance—and vice versa. Fine-grained, homogeneously distributed phases that inhibit hydrogen cracking are required. Austenitic structures are tougher, but more expensive and difficult to manufacture. In addition, harmful precipitates, such as carbides or sigma phases, which weaken the grain boundaries, must be avoided.
- Alloy development with minimal content of expensive elements: High-alloy steels with excellent resistance (e.g., super duplex and high-nickel steels) are very expensive. The use of nickel, molybdenum, and vanadium, for example, improves properties but is cost-intensive and, in some cases, critical in terms of raw materials.