Coarsening and dendritic instability of spheroidal graphite in high silicon cast iron under thermal cycling in the ferritic domain

André Ebel (1) , Mariana Alves Pegoraro , Benoît Malard (1) , Christophe Tenailleau (1) , Jacques Lacaze (1)

1 CIRIMAT - Centre interuniversitaire de recherche et d'ingenierie des matériaux

High silicon ferritic spheroidal graphite cast irons have been developed for high temperature service, in particular under thermal cycling conditions. The theoretical maximum service temperature is defined as the upper limit of the two-phase ferrite+graphite domain, which increases with the alloy silicon content. While isothermal heat treatment close to this temperature showed little evolution of the graphite distribution, thermal cycling led to a significant coarsening of the graphite particles associated with dendritic overgrowth of the large graphite particles. This unexpected behaviour is here observed and described for the first time.

Mots clés: Cyclic heat treatment; dendritic growth; graphite; spheroidal graphite cast iron Funding: none; conflict of interest: none

Domaines: Matériaux

André Ebel, Mariana Alves Pegoraro, Benoît Malard, Christophe Tenailleau, Jacques Lacaze. Coarsening and dendritic instability of spheroidal graphite in high silicon cast iron under thermal cycling in the ferritic domain. Scripta Materialia, 2020, 178, ⟨10.1016/j.scriptamat.2019.11.001⟩. ⟨hal-02363594⟩