Investigation into irradiation effects in ODS steels using ion implantation and micromechanical testing

Oxide Dispersion Strengthened steels are materials for the first wall of proposed nuclear fusion reactors including DEMO. They contain a nanoparticle dispersion of Y2O3 which restricts dislocation motion. The particles act as low energy sites capable of trapping helium. The experiments reported here focus on the mechanical effects of ion implantation on a model Fe-Cr alloy and an ODS equivalent. Samples were helium and iron ion implanted as a simulation of neutron damage and material transmutation. The main restriction of using ion implantation is the limited damage depth available in samples (<3μm), therefore nanoindentation was used to provide information on the surface hardness changes. Transmission Electron Microscopy was used to see how the dislocation structure within these test volumes changes with implantation

Investigation into irradiation effects in ODS steels using ion implantation and micromechanical testing

Oxide Dispersion Strengthened steels are materials for the first wall of proposed nuclear fusion reactors including DEMO. They contain a nanoparticle dispersion of Y2O3 which restricts dislocation motion. The particles act as low energy sites capable of trapping helium. The experiments reported here focus on the mechanical effects of ion implantation on a model Fe-Cr alloy and an ODS equivalent. Samples were helium and iron ion implanted as a simulation of neutron damage and material transmutation. The main restriction of using ion implantation is the limited damage depth available in samples (<3μm), therefore nanoindentation was used to provide information on the surface hardness changes. Transmission Electron Microscopy was used to see how the dislocation structure within these test volumes changes with implantation

Compression of self-ion implanted iron micropillars

Ion implantation causes displacement damage in materials, leading to the formation of small dislocation loops and can cause changes to the material's mechanical properties. Samples of pure Fe were subjected to Fe + implantation at 275°C, producing damage of ∼6 dpa to ∼1 μm depth. Nanoindentation into implanted material shows an increase in hardness compared to unimplanted material. Micropillars were manufactured in cross-section specimens of implanted and unimplanted material and compressed using a nanoindenter. The implanted pillars have a deformation mode which differs markedly from the unimplanted pillars but show no change in yield-stress. This suggests that the controlling mechanism for deformation is different between nanoindentation and micropillar compression and that care is needed if using micropillar compression to extract bulk properties of irradiated materials. © 2012 Elsevier B.V. All rights reserved

Two-dimensional nanosheets produced by liquid exfoliation of layered materials.

If they could be easily exfoliated, layered materials would become a diverse source of two-dimensional crystals whose properties would be useful in applications ranging from electronics to energy storage. We show that layered compounds such as MoS(2), WS(2), MoSe(2), MoTe(2), TaSe(2), NbSe(2), NiTe(2), BN, and Bi(2)Te(3) can be efficiently dispersed in common solvents and can be deposited as individual flakes or formed into films. Electron microscopy strongly suggests that the material is exfoliated into individual layers. By blending this material with suspensions of other nanomaterials or polymer solutions, we can prepare hybrid dispersions or composites, which can be cast into films. We show that WS(2) and MoS(2) effectively reinforce polymers, whereas WS(2)/carbon nanotube hybrid films have high conductivity, leading to promising thermoelectric properties