(Düsseldorf) – Scientists from the Max Planck Institute for Iron Research GmbH (MPIE) and their colleagues from Tsinghua University China and the Norwegian University of Science and Technology say they have found a way to stop hydrogen-induced cracks in high-strength steels. Embrittlement has become one of the main problems hindering the implementation of the hydrogen economy. High-strength alloys are required in the automotive and aviation industries for the construction of lightweight components and in all other components that are used to store and transport hydrogen.
“Steels make up 90 percent of the global metal alloy market and high-strength steels can be particularly susceptible to hydrogen embrittlement,” explains Binhan Sun, topic leader for hydrogen embrittlement in high-performance alloys at MPIE. “Therefore, our goal was to find a cost-effective, scalable strategy to make high-strength steels more resistant to hydrogen while maintaining their mechanical performance.”
To do this, the scientists implemented manganese-rich areas into the microstructure of the steel “to blunt cracks and trap hydrogen in them” and thus stop cracks from spreading. 
“We tested our method with high-strength manganese steels, in which we created an extremely high number density of manganese-rich buffer zones. These buffer zones represent dead ends for cracks by blunting sharp cracks,” says Dirk Ponge, head of the MPIE “Mechanism-based Alloy Design” group, who is overseeing the research project. “This makes the steel twice as resistant to hydrogen as conventional chemically homogeneous steels, regardless of when and how hydrogen has penetrated the material.”
The method can “in principle be applied to over ten established types of steel”. According to the information, the scientists also see further possible uses for other alloy systems, such as multi-phase titanium alloys. However, before the spectrum of alloys is expanded, the researchers want to find different methods “to precisely create buffer zones with chemical heterogeneity within the structure.” These could further enhance the crack resistance effect and better fit established industrial processing routes, according to an MPIE release. The research results were published in the journal Nature Materials.
deep link
https://www.mpie.de/4581011/dead-ends-for-hydrogen-induced-cracks
https://dx.doi.org/10.1038/s41563-021-01050-y
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Coil storage of the steel manufacturer Salzgitter AG / © Salzgitter AG
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Chemical heterogeneity within the microstructure leads to improved resistance to hydrogen-induced cracking and thus suppresses hydrogen-induced premature material failure (left image). This microstructure was set in a high-strength manganese-containing steel in which a high density of ultrafine manganese-rich zones were created that serve to blunt and arrest hydrogen-induced microcracks (some of the manganese-rich buffer zones are marked by red ellipses in the right image). Source: MPIE © Graphics: MPIE / The figure was reproduced from B. Sun et al, Nat. Mater. 2021
