Open AccessANALYSIS AND THERMODYNAMIC STABILITY OF NUCLEI IN SPHEROIDAL GRAPHITE IN Fe–C–Si ALLOYS
Author(s) -
Marica Prijanovič Tonkovič,
Primož Mrvar,
Maja Vončina,
Črtomir Donik,
Matjaž Godec,
Mitja Petrič
Publication year - 2021
Publication title -
materiali in tehnologije
Language(s) - English
Resource type - Journals
eISSN - 1580-3414
pISSN - 1580-2949
DOI - 10.17222/mit.2021.063
Subject(s) - graphite , materials science , tin , metallurgy , cast iron , barium , analytical chemistry (journal) , chemistry , chromatography
The paper describes the graphite nuclei constitution for spheroidal graphite cast iron melted in a cupola furnace, which is treated by the addition of magnesium and inoculated with a barium-based inoculant. Two samples of spheroidal cast iron were analysed, differing only in tin content. Field-emission scanning electron microscopy (FE -SEM) with energy-dispersive X-ray spectroscopy (EDS) was used to analyse the nuclei. The thermodynamic calculation of the phase equilibria and the associated free formation energies of the alloys were calculated and compared with metallographic observations. It was found that the nuclei in the spheroidal graphite are different in shape and composition. Spherical and rectangular ones were found, and in many cases the porosity was present at the nuclei. The nuclei consisted of different compounds such as (Mg,Ca)S, MgO, (Mg,Al,Si)N. The amount of Sn only affected the pearlite content, and there were no Ba and rare earths present in the nuclei.