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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/Esversus ρ/ρsresulted in (E/Es)=(ρ/ρs)2.8. Novel, δ-Fe phase platelets have been observed in α-Fe components fabricated by EMB.

Abstract: A theoretical study of structural and electronic properties of β-HMX crystal is performed using density-functional theory (DFT). The total density of states (TDOS) is presented. The atomic orbit projected density of state (PDOS) from the p-type orbit of C, N, O and the s-type orbit of H is discussed. The study by analyzing the PDOS shows that the structure of β-HMX crystal possesses C-H...O intra- and inter-molecular hydrogen-bonding. There exists a hydrogen bonding between H5-1s and O12-2p orbits, between H19-1s and O28-2p orbits of intra molecules, and between H19-1s and O24-2p orbits of inter molecules. The Mulliken population analysis is also made.