Functionally graded stainless steels with tailored grain boundary serration

Y. Nie, Y. T. Chang, M. A. Charpagne

Research output: Contribution to journalArticlepeer-review


We demonstrate the possibility of spatially controlling the degree of grain boundary serration in functionally graded stainless steels, by alloying powder mixtures on-the-fly during directed energy deposition additive manufacturing. Grain boundary serration is an attractive feature in polycrystalline microstructures, as it confers superior resistance to crack propagation and hot corrosion. Quantitative measurements at the microstructure scale coupled with thermodynamic calculations allow us to propose a mechanism to explain the origin of grain boundary serration. The formation of transient δ ferrite during solidification and its subsequent dissolution during cooling, governed by the Cr/Ni ratio, leads to the formation of remnant ferrite particles that hinder the growth of austenite grains in the solid state via a Smith-Zener pinning phenomenon. This finding opens new perspectives for grain boundary engineering, in-situ during additive manufacturing.

Original languageEnglish (US)
Article number115714
JournalScripta Materialia
StatePublished - Dec 2023
Externally publishedYes


  • Additive manufacturing
  • Functionally graded materials
  • Grain boundaries
  • Serration
  • Stainless steel

ASJC Scopus subject areas

  • General Materials Science
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering
  • Metals and Alloys


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