The purpose of this work was to propose and evaluate a new composition for a bioactive glass-ceramic starting from the well-known 45S5 commercial product. Thus, we developed a modified version, including MgO, an oxide that turned out to induce superior mechanical properties and improved biological response. This had the following molar percentages: 46.1% SiO2, 2.6% P2O5, 16.9% CaO, 10.0% MgO, and 24.4% Na2O. The precursor alkoxides and nitrates were processed by a standard sol-gel technique, resulting in a glass-ceramic target, suitable for laser ablation experiments. Combeite (Na2Ca2Si3O9) was identified as a main crystalline phase within the calcined sol-gel powder, as well as in the case of the target sintered at 900 °C. The thin films were deposited on silicon substrates, at room temperature or 300 °C, being subsequently characterized from the material point of view, as well as in terms of bioactivity in simulated conditions and biocompatibility in relation to human fibroblast BJ cells. The investigations revealed the deposition of nanostructured glassy layers with a low proportion of crystalline domains; it was shown that a higher substrate temperature promoted the formation of surfaces with less irregularities, as a consequence of material arrangement into a shell with better morphological homogeneity. The complex elemental composition of the target was successfully transferred to the coatings, which ensured pronounced mineralization and a stimulating environment for the cell cultures. Thereby, both samples were covered with a thick layer of apatite after immersion in simulated body fluid for 28 days, and the one processed at room temperature was qualified to be the best in relation to the cells.

The paper develops a model based on the finite element analysis of the crack initiation and propagation in the generation IV structural materials due to the liquid metal embrittlement (LME) phenomenon. The stress-strain experimental curves obtained at 400 ºC by testing in the liquid lead and air were converted as the Ramberg - Osgood constitutive equations by proposing a new method to obtain the strain hardening coefficient. To estimate the accuracy of prediction are used the residual and standardised residual in the context of regression analysis. Further, a model based on the Gurson–Tvergaard-Needleman approach (GTN) was set up to evaluate the crack initiation and propagation under the LME conditions. An application of the developed micro-mechanical model that predicts the crack initiation and propagation in the Compact –Tension (CT) specimen due to LME is performed. The model is practical in the structural integrity activities framework of the structural materials that will be used in the ALFRED demonstrator, which will be build-up at RATEN ICN, Romania.

The paper aims to investigate the mechanical properties of tubes having a small diameter and made from new steels called ODS steels Oxide Dispersion Strengthened steels). These new materials are candidate materials for fuel claddings in the generation IV reactors. This work contributes to original results to the experimental program carried out by RATEN ICN Pitesti in the framework of the FP7 European MatISSE Project (Materials� Innovations for a Safe and Sustainable nuclear �n Europe). The experimental method used for the investigating of the mechanical properties of ODS steel tubes is a non-standard method, known as Ring Tension Test (acronym - RTT). It is recommended for the mechanical testing of tubes with thinner walls and reduced inner diameter. The main advantage of RTT is that the tested sample maintains the initial geometry of the component from which has been made. For the experimental RTT tests, the ODS tubes were provided by MatISSE Project participant, CEA France. Tubes are in two different compositions: Fe-9Cr ODS and Fe-14Cr ODS. For a better understanding of the ODS mechanical properties, some further investigation on the scanning electron microscopy is carried out.

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