Journal of Materials Science

, Volume 21, Issue 2, pp 692–704

A fractographic study of hydrogen-assisted cracking and liquid-metal embrittlement in nickel

  • S. P. Lynch
Article

DOI: 10.1007/BF01145543

Cite this article as:
Lynch, S.P. J Mater Sci (1986) 21: 692. doi:10.1007/BF01145543

Abstract

Metallographic and fractographic studies of crack growth in nickel polycrystals and single crystals in a number of environments are described. “Brittle” intercrystalline and transcrystalline cleavage-like fractures were observed for specimens tested in liquid mercury, liquid lithium, liquid sodium, gaseous hydrogen, and for hydrogen-charged specimens tested in air. “Brittle” fractures were associated with considerable slip, and dimples/tear ridges were observed on fracture surfaces, suggesting that crack growth occurred by localized plastic flow. There were remarkable similarities between adsorption-induced liquid-metal embrittlement and hydrogen-assisted cracking which, along with other observations, suggested that adsorbed hydrogen at crack tips was responsible for hydrogen-assisted cracking. It is concluded that adsorbed atoms weaken interatomic bonds at crack tips thereby facilitating the nucleation of dislocations and promoting crack growth by localized plastic flow.

Copyright information

© Chapman and Hall Ltd. 1986

Authors and Affiliations

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