Nature Communications· 2015Q1
The dual role of coherent twin boundaries in hydrogen embrittlement
- 250citations
- Q1SCImago
- 2015year
Short summary
Coherent twin boundaries (CTBs) in Ni-base superalloys are surprisingly susceptible to initiating cracks under hydrogen embrittlement, despite their known benefits for strength and corrosion resistance.
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Key points
- Coherent twin boundaries (CTBs) are the most susceptible microstructural features for crack initiation in Ni-base superalloys under hydrogen embrittlement.
- CTBs, usually beneficial for mechanical properties, unexpectedly facilitate hydrogen-assisted fracture initiation.
- CTBs also exhibit resistance to crack propagation, indicating separate mechanisms for initiation and propagation.
- This dual role challenges existing lifetime prediction models for engineering alloys.
AI-generated from the title and abstract; the full text is not read.
Abstract
Hydrogen embrittlement (HE) causes engineering alloys to fracture unexpectedly, often at considerable economic or environmental cost. Inaccurate predictions of component lifetimes arise from inadequate understanding of how alloy microstructure affects HE. Here we investigate hydrogen-assisted fracture of a Ni-base superalloy and identify coherent twin boundaries (CTBs) as the microstructural features most susceptible to crack initiation. This is a surprising result considering the renowned beneficial effect of CTBs on mechanical strength and corrosion resistance of many engineering alloys. Remarkably, we also find that CTBs are resistant to crack propagation, implying that hydrogen-assisted crack initiation and propagation are governed by distinct physical mechanisms in Ni-base alloys. This finding motivates a re-evaluation of current lifetime models in light of the dual role of CTBs. It also indicates new paths to designing materials with HE-resistant microstructures. When exposed to hydrogen, alloys may lose their ductility and fracture unexpectedly, a phenomenon known as hydrogen embrittlement. Here, the authors investigate hydrogen embrittlement in a Ni-based superalloy and find that coherent twin boundaries are susceptible to crack initiation.
The authors' abstract, as published at the source. Nature Communications, 2015 · DOI ↗
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Field: Metals and Alloys
Metals and AlloysMaterials Science