Multi-disciplinary team of researchers delve deep into hydrogen degradation and embrittlement with hopes to speed up transitions in industries
Here’s an article posted in Innovation News Network about the risks and solutions of hydrogen safety through the research of Stony Brook.
According to the article,
- Research led by Professor T A Venkatesh at Stony Brook University
- Focus on understanding degradation such as fatigue crack growth caused by hydrogen
- Improve scientific and technological knowledge for hydrogen storage and transport
- Hydrogen identified as clean fuel with potential for power generation and transmission.
Hydrogen Embrittlement (HE) is a huge problem the world faces, as it increases infrastructure and maintenance costs, due to which industries let go of the very idea of using hydrogen as a fuel, let alone implementing it.
Hydrogen embrittlement (HE) is a complex phenomenon that occurs when hydrogen is absorbed into a metal, causing it to become brittle and prone to cracking. This process can lead to significant reductions in the metal’s ductility and tensile strength, making it more susceptible to failure under mechanical stress.
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Mechanism of Hydrogen Embrittlement
The exact mechanism of hydrogen embrittlement is not fully understood, but several contributing micro-mechanisms have been proposed. These include:
- Hydride-Induced Embrittlement: The formation of brittle hydrides within the metal can lead to the creation of voids and cracks.
- Internal Pressure: At high hydrogen concentrations, absorbed hydrogen species recombine in voids to form hydrogen molecules (H2), creating internal pressure. This pressure can increase to levels where cracks form, commonly referred to as hydrogen-induced cracking (HIC).
- Hydrogen Enhanced Localized Plasticity (HELP): Hydrogen increases the nucleation and movement of dislocations at a crack tip, leading to localized ductile failure at the crack tip with less deformation in the surrounding material, giving a brittle appearance to the fracture.
- Hydrogen Decreased Dislocation Emission: Molecular dynamics simulations show a ductile-to-brittle transition caused by the suppression of dislocation emission at the crack tip by dissolved hydrogen, preventing the crack tip from rounding off and leading to brittle-cleavage failure.
- Hydrogen Enhanced Decohesion (HEDE): Interstitial hydrogen lowers the stress required for metal atoms to fracture apart, which can occur when the local concentration of hydrogen is high, such as at stress concentrators or in the tension field of edge dislocations.
Causes of Hydrogen Embrittlement
Hydrogen embrittlement can occur due to various sources of hydrogen, including:
- Gaseous Hydrogen: Molecular hydrogen can lead to hot hydrogen attack, but it does not result in embrittlement. Conversely, atomic hydrogen can cause embrittlement by rapidly dissolving into the metal at ambient temperature.
- Electrochemical Sources: Hydrogen can be introduced into the metal during electrochemical processes such as electroplating, pickling, etching, or cleaning
- Manufacturing Processes: Hydrogen can be introduced during manufacturing processes like welding or molten metal handling
- Environmental Factors: Hydrogen can be introduced through environmental factors such as corrosion, cathodic protection, or exposure to acidic or alkaline solutions
Prevention and Mitigation
To prevent or mitigate hydrogen embrittlement, various strategies can be employed:
- Material Selection: Choosing materials that are resistant to hydrogen embrittlement, such as high-strength steels, can help reduce the risk of failure
- Hydrogen Control: Controlling the amount of hydrogen present in the metal through proper handling and storage practices can help prevent embrittlement
- Stress Reduction: Reducing mechanical stress on the metal can help prevent crack growth and failure
- Coatings and Surface Treatments: Applying coatings or surface treatments that reduce hydrogen absorption can help prevent embrittlement
Overall, hydrogen embrittlement is a complex phenomenon that requires a comprehensive understanding of its mechanisms and causes to effectively prevent and mitigate its effects.
Interestingly, we have some other posts related to this content:
Minimizing Hydrogen Leakage – EDF Recommendations
EDF emphasizes minimizing hydrogen leaks for climate benefits, advocating good engineering, inspections, and local production to maximize hydrogen’s environmental advantages.
