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Journal of Materials Science

, Volume 20, Issue 9, pp 3329–3338 | Cite as

Mechanisms of stress-corrosion cracking and liquid-metal embrittlement in Al-Zn-Mg bicrystals

  • S. P. Lynch
Papers

Abstract

Metallographic and fractographic studies of intercrystalline fracture in high-purity Al-6Zn-3Mg bicrystals in inert, liquid metal, and water environments are described. The effects of variations in grain-boundary microstructure on fracture and the effects of cathodically charging specimens with hydrogen prior to testing in inert environments were also investigated. Mechanisms of liquid-metal embrittlement, stress-corrosion cracking and pre-exposure embrittlement are discussed in the light of these results. The observations suggest that liquid-metal embrittlement and stress-corrosion cracking generally occur by a plastic-flow/microvoid-coalescence process that is more localized than that which occurs in inert environments. It is proposed that adsorbed liquid metal or hydrogen atoms weaken interatomic bonds at crack tips, thereby facilitating the nucleation of dislocations and promoting the coalescence of cracks with voids.

Keywords

Fracture Surface Interatomic Bond Hydrogen Effect Inert Environment Magnesium Hydride 

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Copyright information

© Chapman and Hall Ltd 1985

Authors and Affiliations

  • S. P. Lynch
    • 1
  1. 1.Department of DefenceAeronautical Research Laboratories, Defence Science and Technology OrganisationMelbourneAustralia

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