Microstructures and properties of solid and reticulated mesh components of pure iron fabricated by electron beam melting

Abstract

This research examines rapidly solidified, atomized pure iron powder and solid and reticulated mesh components fabricated by electron beam melting (EBM) from this powder precursor. Especially significant was the characterization of associated microstructures and corresponding mechanical properties. Atomized Fe powder was used to fabricate solid and reticulated mesh components by EBM. Powder and component microstructures and phase structures were examined by light (optical) metallography, scanning electron microscopy, X-ray diffractometry, and transmission electron microscopy. Corresponding Vickers microindentation hardness measurements were also made and compared to tensile data along with measurements of dynamic stiffness for mesh components having varying densities. The atomized Fe powder was observed to contain δ-Fe which was retained in the solid, EBM-fabricated components where it was observed to be homogeneously distributed in equiaxed α-Fe grains as δ-phase platelets measuring ∼0.5μm to 2μm in length and ∼40nm thick; coincident with the α-Fe matrix {100} or {110} planes. A log–log plot of E/Es versus ρ/ρs resulted in (E/Es)=(ρ/ρs)2.8. Novel, δ-Fe phase platelets have been observed in α-Fe components fabricated by EMB.