Deviations from cooperative growth mode during eutectoid transformation: Insights from a phase-field approach

Kumar Ankit, Rajdip Mukherjee, Tobias Mittnacht, Britta Nestler

Research output: Contribution to journalArticle

16 Scopus citations

Abstract

The non-cooperative eutectoid transformation relies on the presence of pre-existing cementite particles in the parent austenitic phase and yields a product, popularly known as the divorced eutectoid. Under isothermal conditions, two of the important parameters that influence the transformation mechanism and determine the final morphology are undercooling (below the A1temperature) and interparticle spacing. Although the criteria that govern the morphological transition from lamellar to divorced is experimentally well established, numerical studies giving a detailed exposition of the non-cooperative transformation mechanism have not been reported extensively. In the present work, we employ a multiphase-field model that uses thermodynamic information from the CALPHAD database to numerically simulate the pulling-away of the advancing ferrite-austenite interface from cementite, which results in a transition from lamellar to divorced eutectoid morphology in Fe-C alloy. We also identify the onset of a concurrent growth and coarsening regime at small interparticle spacing and low undercooling. We analyze the simulation results to unravel the essential physics behind this complex spatial and temporal evolution pathway and amend the existing criteria by constructing a Lamellar-Divorced-Coarsening (LDC) map.

Original languageEnglish (US)
Pages (from-to)204-210
Number of pages7
JournalActa Materialia
Volume81
DOIs
StatePublished - Dec 2014
Externally publishedYes

    Fingerprint

Keywords

  • Coarsening
  • Divorced eutectoid transformation
  • Non-cooperative growth
  • Phase-field method

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Ceramics and Composites
  • Polymers and Plastics
  • Metals and Alloys

Cite this