Early stages of liquid-metal embrittlement in an advanced high-strength steel

Y. Ikeda, R. Yuan, A. Chakraborty, H. Ghassemi-Armaki, J. M. Zuo, Christoph Robert Eduard Maass

Research output: Contribution to journalArticlepeer-review


Grain-boundary degradation via liquid-metal embrittlement (LME) is a prominent and long-standing failure process in next generation advanced high-strength steels. Here we reveal, well ahead of the crack tip, the presences of nano-scale grains of intermetallic phases in Zn-infiltrated but uncracked grain boundaries with scanning- and 4D transmission electron microscopy. Instead of the often-reported Zn-rich Fe-Zn intermetallics, the nano-scale phase in the uncracked infiltrated grain boundaries is identified as the Γ-phase, and its presence reveals the local enhancement of strain heterogeneities in the grain boundary network. Based on these observations, we argue that intermetallic phase formation is not occurring after cracking and subsequent liquid Zn infiltration but is instead one of the primary nanoscopic drivers for grain-boundary weakening and crack initiation. These findings shift the focus of LME from micro- and meso-scale crack investigations to the very early stages immediately following Zn diffusion, after which secondary phase nucleation and growth emerge as the root-cause for failure.

Original languageEnglish (US)
Article number100196
JournalMaterials Today Advances
StatePublished - Mar 2022


  • 4-Dimensional scanning transmission electron microscopy
  • Advanced high strength steels
  • Liquid metal embrittlement
  • Transmission electron microscopy

ASJC Scopus subject areas

  • Materials Science(all)
  • Mechanical Engineering


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