The French group Safran is among the world leaders in the field of superalloys metallurgy which appeared in the United States in the 1940s. This position, shared with General Electric, Pratt & Whitney or Rolls-Royce must be defended, especially with regards to the American supremacy. The risk of dilapidation of the French know-how in the field of metallurgy was stressed in a joint report of the Academy of Sciences and Academy of Technology in 2011. At the national scale, metallurgy accounts for 1.5 million jobs and will provide more than 100,000 hirings per year by 2020, with a significant increase in the need for highly qualified categories. Through the development of projects on superalloys forming, resulting microstructures and in-service properties (especially for aeronautics), the OPALE chair will educate metallurgists who will later on contribute to the development the French industry and to maintain its competitiveness at the world scale in the future. The project aims at improving the mechanical behaviour of polycrystalline Nickel base superalloys, by tailoring the microstructure of as-shaped pieces. Those alloys are used for manufacturing turbojet engine components, due to their excellent mechanical strength at high temperature. Improving the material properties is a necessary condition for increasing the engine temperature and energetic efficiency. The OPALE project is therefore in line with the objectives “Vision 2020” defined by the ACARE. The OPALE project meets the needs of the Safran group and combines the expertise of the CEMEF (MINES ParisTech, UMR CNRS) on the process-microstructure relationship, and the expertise of the P’ institute (UPR CNRS, ISAE/ENSMA) on the impact of microstructure on the in-service mechanical properties. The chair aims at strengthening and expanding collaborations which already exist between some of the companies of the Safran group and these two research centers. It will help in structuring research on superalloys in Safran, and in establishing long lasting links with the most relevant research labs in the field. This organization is set up to handle all the topics that will be addressed in the chair to make the metallurgy of tomorrow emerge. The metallurgy of the future will indeed rely on predictive models covering the entire material processing chain as well as its behavior and evolution in service. Such chained models will be developed within the OPALE project. The person proposed to be the chair holder, Nathalie Bozzolo, is an experienced scientist who joined the CEMEF recently (2009) to develop activities in that research field in connection with industry. Expert in physical metallurgy, and especially in the analysis of microstructural mechanisms, she is at the junction between the two branches of the project: process-microstructure and microstructure-properties relationships. The three other involved researchers complete the large competency spectrum needed to achieve that ambitious project: from fine material and properties analysis to process-microstructure and microstructure-properties relationship modelling, including the development of new numerical simulation tools and original experimental setups. Fundamental studies (experimental and numerical developments, metallurgical mechanism analysis) will provide new or better knowledge which will applied in other studies in direct connection with industrial issues (support for optimizing new processes and for processing of new alloys). In the long run, the output of the project will be applicable to types of alloys (Ti base, Al base, steels) used in aeronautics, but also in other fields like transportation or energy.

The aim of this project is to produce nanothermites of controlled metal-oxide architecture and interface using efficient processes transferable to an industrial production, in order to guarantee stability of behaviors and performances and to increase reaction rates. The current approaches used in the nanomaterials community for multiple applications taking advantage of the reduction of the size of the structures at nanometric scale are starting to be implemented to the nanothermites domain. Nanopowders are simply mixed and the results obtained are quite promising. However, during mixing, strong local heterogeneities in the particle distribution are inevitable, and the manipulation and the synthesis of these powder mixtures impose safety constraints ('worker exposure') which could lead to significant costs for an eventual industrial development. Considering this, it is interesting to find an alternative of this simple mixture of nanopowders and to consider nanostructured metal-oxide composites in which the two materials are intimately linked and homogeneously distributed even at small scale. These nanocomposites can have many architectures: individual coating of aluminum nanoparticles with the oxide, coating of oxide nanoparticles with aluminum, ... with different possibilities of shapes and dimension. In this project we propose a physicochemical and modeling approach to perform a rational design of nanothermites, from several metal-oxide pairs (Al / CuO, Al / Sb2O5, Al / WO3 ...) by controlling the process parameters: the dimensions of the particles (metal and oxide), their morphology, their interface, and the porosity of the architecture. Several nano thermites will be synthesized according to different protocols then characterized and studied in combustion and by heat treatments. The results obtained experimentally will be totally original and very useful to understand the physicochemical processes involved. They will also be used to develop a detailed kinetic model of combustion.