New Aspects Regarding the Structure of Spheroidal Cast Iron Carbon Inclusions Revealed by WAXD Investigations
The paper addresses mainly the atomic structure of the spheroidal carbon inclusions (CIs) from a magnesium treated cast iron. The qualitative phase analysis based on diffraction patterns shows that the CI by-products contain carbon, ferrite and iron oxides. Based on peak angular positions and their half-width at half-intensity, the distances between graphenes and the average height of the graphene stack were calculated. To comply with EN 13005 standard, the calculated results include the extended uncertainties U(95%). The Wide Angle X-ray Diffraction (WAXD) data proves clearly that the CI from the spheroidal cast iron do not have a polycrystalline graphite structure, but rather a turbostratic graphite-like structure with the d(002) surprisingly close to the graphite structure, e.g. to 3.34 Å. If this conclusion is accepted, a new approach of the nucleation and growth mechanisms of the CIs in spheroidal cast irons as turbostratic graphite-like structures should be explored, while the mechanisms based on crystallographic considerations should be revised.
Adel Nofal and Mohamed Waly
I. Pencea et al., "New Aspects Regarding the Structure of Spheroidal Cast Iron Carbon Inclusions Revealed by WAXD Investigations", Key Engineering Materials, Vol. 457, pp. 120-125, 2011