The current magnetic confinement nuclear fusion power reactor concepts going beyond ITER are based on assumptions about the availability of materials with extreme mechanical, heat, and neutron load capacity. In Europe, the development of such structural and armour materials together with the necessary production, machining, and fabrication technologies is pursued within the EFDA long-term fusion materials programme. This paper reviews the progress of work within the programme in the area of tungsten and tungsten alloys. Results, conclusions, and future projections are summarized for each of the programme´s main subtopics, which are: (1) fabrication, (2) structural W materials, (3) W armour materials, and (4) materials science and modelling. It gives a detailed overview of the latest results on materials research, fabrication processes, joining options, high heat flux testing, plasticity studies, modelling, and validation experiments

A set of oxide and chalcogenide tetrahedral glasses is investigated using molecular dynamics simulations. We show that the changes in the Ge composition affect mostly bending around germanium in binary Ge-Se systems, leaving Se-centered bending almost unchanged. In contrast, the corresponding Se twisting (quantified by the dihedral angle) depends on the Ge composition and is reduced when the system becomes rigid. It is also shown that angles involving the fourth neighbor around Ge is found to change when the system enters the stressed rigid phase. The same analysis reveals that unlike stoichiometric selenides such as GeSe2 and SiSe2, germania and silica display large standard deviations in the bond angle distributions. Within bond-bending constraints theory, this pattern can be interpreted as a manifestation of broken (i.e., ineffective) oxygen bond-bending constraints, whereas the silicon and germanium bending in oxides is found to be similar to the one found in flexible and intermediate Ge-Se systems. Our results establish the atomic-scale foundations of the phenomenological rigidity theory, thereby profoundly extending its significance and impact on the structural description of network glasses.

The microscopic origin of the intermediate phase in two prototypical covalently bonded $A_x{B}_{1-x}$ network glass forming systems, where $A=\text{Ge}$ or Si, $B=\text{Se}$, and $0\le x\le 1$, was investigated by combining neutron diffraction with first-principles molecular-dynamics methods. Specifically, the structure of glassy ${\text{GeSe}}_4$ and ${\text{SiSe}}_4$ was examined, and the calculated total structure factor and total pair-correlation function for both materials are in good agreement with experiment. The structure of both glasses differs markedly from a simple model comprising undefective $A{B}_4$ corner-sharing tetrahedra in which all $A$ atoms are linked by $B_2$ dimers. Instead, edge-sharing tetrahedra occur and the twofold coordinated Se atoms form three distinct structural motifs, namely, ${\text{Se-Se}}_2$, Se-SeGe (or Se-SeSi), and ${\text{Se-Ge}}_2$ (or ${\text{Se-Si}}_2$). This identifies several of the conformations that are responsible for the structural variability in ${\text{Ge}}_x{\text{Se}}_{1-x}$ and ${\text{Si}}_x{\text{Se}}_{1-x}$ glasses, a quantity that is linked to the finite width of the intermediate phase window.

The solubilization mechanism of lipid membranes in the presence of Triton X-100 (TX-100) is investigated at molecular resolution using hybrid particle field–self consistence field simulations.