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Guilherme Mazui

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What is the Difference Between Hydrogen Embrittlement and Stress Corrosion Cracking?

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Hydrogen embrittlement and stress corrosion cracking are two distinct processes that can lead to the degradation of metals. The key difference between them lies in the factors that contribute to their occurrence:

  1. Hydrogen Embrittlement: This is a reduction in the ductility or toughness of a metal due to the absorption of hydrogen. It can occur in both alloys and pure metals. Hydrogen embrittlement can be classified into two types: internal hydrogen embrittlement and hydrogen-assisted stress-corrosion cracking (HSCC). In the presence of active corrosion, usually as pits or crevices (polarized anodically), the cracking is generally called stress-corrosion cracking (SCC), but should more properly be called HSCC.
  2. Stress Corrosion Cracking: This is the growth of crack formation in a corrosive environment, and it occurs due to the influence of tensile stress and a corrosive atmosphere. It is applicable only for alloys, not for pure metals. Stress corrosion cracking is driven by both anodic dissolution and hydrogen embrittlement, but their relative contributions depend on the environment, alloy compositions, plate thicknesses, and tempers.

In summary, hydrogen embrittlement is related to the absorption of hydrogen in metals, while stress corrosion cracking involves the interaction of tensile stress and a corrosive environment. The two processes can act independently or in combination, leading to the degradation of metals under specific conditions.

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  • What is the Difference Between Hydrogen Embrittlement and Stress Corrosion Cracking?
  • Comparative Table: Hydrogen Embrittlement vs Stress Corrosion Cracking

    • Comparative Table: Hydrogen Embrittlement vs Stress Corrosion Cracking

    Here is a table comparing the key differences between hydrogen embrittlement and stress corrosion cracking:

    Feature Hydrogen Embrittlement Stress Corrosion Cracking
    Definition A reduction in the ductility of a metal due to the absorbed hydrogen. The growth of crack formation in a corrosive environment, occurring due to the influence of tensile stress and a corrosive medium.
    Applicability Occurs in both alloys and pure metals. Occurs only in alloys, not in pure metals.
    Initiation Caused by the absorption of hydrogen into the metal. Caused by the presence of a corrosive environment and tensile stress.
    Mechanism Hydrogen ions (protons) react with the metal, forming a high-strength covalent bond, making it more brittle. Cracks form at areas of high tensile stress, and corrosion assists in the fracture process by reducing the local stress required for cracking.
    Prevention Reducing hydrogen levels in the material or avoiding environments with high hydrogen concentrations. Selecting materials resistant to stress corrosion cracking, avoiding corrosive environments, and controlling stress levels.

    Please note that the information in this table is summarized from the provided search results.

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    Guilherme Mazui

    Guilherme Mazui is graduated in journalism from the Federal University of Minas Gerais (UFMG) and a master's degree in Communication from the University of São Paulo (USP). In addition, he has experience in advertising writing and has worked as a content editor in several companies.