Dual-phase 9Cr-ODS (oxide dispersion-strengthened) steel consisting of residual-α ferrite and α′ martensite has excellent high-temperature strength. This study describes the microstructure of dual-phase 9Cr-ODS steels characterized by atom-probe tomography in order to compare oxide-particle dispersion states in each phase. This revealed that nano-size oxide particles were of the same chemical composition and that their mean size was about 3 nm in each phase. On the other hand, the number density in the residual-α phase was about four times higher than that of the α′ phase. These results indicate that the dense distribution of the oxide particles in the residual-α phase contribute to the excellent high-temperature strength of 9Cr-ODS steel.

We report a successful atom probe tomography of hydrides in hydrogenation-disproportionated Nd–Fe–B powder using a green femtosecond laser. The atom probe specimens were prepared from one particle of powder using the focused ion beam lift-out method. The atom probe tomography taken from an α-Fe/NdH2 structure suggested that B and Ga (trace added element) were partitioned in the NdH2 phase. The hydrogen concentration of 64 at% determined from the atom probe analysis was in excellent agreement with the stoichiometry of the NdH2 phase.Research Highlights► Atom probe tomography of hydrides in hydrogenation-disproportionated Nd–Fe–B powder. ► Successful quantitative analysis of hydrogen from NdH2 lamellae. ► Direct observation of individual hydrogen atoms using laser assisted atom probe.

The distribution of Mn in a Ga0.963Mn0.037As ferromagnetic semiconductor film has been characterized by the three-dimensional atom probe (3DAP) technique. Atom probe specimens were directly prepared from the (Ga,Mn)As film grown epitaxially on a p-type GaAs substrate by the lift-out technique using a scanning electron microscope/focused ion beam system. The atom probe elemental map revealed that the Mn atoms in the Ga0.963Mn0.037As are uniformly dissolved without forming any nanometer-sized clusters.

Friction welded Pd40Ni40P20/Pd40Cu30Ni10P20 metallic glass interface has been characterized by energy filtering transmission electron microscopy. The interface is fully amorphous with a gradual compositional change of Cu and Ni in the range of 30 nm. By annealing above Tg, the interdiffusion of Cu and Ni progressed in the supercooled liquid region, and the crystallization occurred from the Pd40Ni40P20 glass.