Homogeneous Cu-Fe super saturated solid solutions prepared by severe plastic deformation

A Cu-Fe nanocomposite containing 50 nm thick iron filaments dispersed in a copper matrix was processed by torsion under high pressure at various strain rates and temperatures. The resulting nanostructures were characterized by transmission electron microscopy, atom probe tomography and M\"ossbauer spectrometry. It is shown that alpha-Fe filaments are dissolved during severe plastic deformation leading to the formation of a homogeneous supersaturated solid solution of about 12 at.% Fe in fcc Cu. The dissolution rate is proportional to the total plastic strain but is not very sensitive to the strain rate. Similar results were found for samples processed at liquid nitrogen temperature. APT data revealed asymmetric composition gradients resulting from the deformation induced intermixing. On the basis of these experimental data, the formation of the supersaturated solid solutions is discusse

Rapport I.11. Variations hydro-climatiques dans le bassin du Nil

If some not negligible climatological changes occured upon the river Nile basin from the end of the last century, they certainly had to produce significant resulting effects on the level with principal hydrological variables that characterize the catchment area of this, one of the most imposing river of our planet. The resulting effects are of an extreme importance for agricultural, water resources management and sedimentation problems of the field that particularly interests our Project. Herein is presented the summary of a statistical study, which object was to discriminate the effects of eventual climatological changes in the observed flows series, at different main stations of the river Nile basin.Si des changements climatiques non négligeables ont eu lieu au-dessus du bassin du Nil depuis la fin du siècle dernier, ils ont dû nécessairement produire des effets résultants significatifs au niveau des principales variables hydrologiques qui caractérisent le bassin versant de ce fleuve, l’un des plus imposants de notre planète. Ces effets résultants sont d’une extrême importance pour les problèmes d’agriculture, de gestion des ressources en eau, et de sédimentation, domaine qui intéresse particulièrement notre Projet. Nous présentons ici le résumé d’une étude statistique qui a pour but de discerner les effets d’éventuels changements climatiques dans les séries observées de débits en diverses stations principales du bassin du Nil.Quelennec R. E. Rapport I.11. Variations hydro-climatiques dans le bassin du Nil. In: Influence des activités de l'homme sur le cycle hydrométéorologique. Compte rendu des treizièmes journées de l'hydraulique. Paris, 16-18 septembre 1974. Tome 1, 1975

Rapport II.8 Intérêt de l'analyse des profils de plage pour l'étude de la dynamique sédimentaire littorale. Cas du littoral du delta du Nil

After a brief review of the main characteristics of the littoral of the Nile delta and of some equations used for the simulation of equilibrium beach profiles, the author propose a system of two empirical relationships which can be used for discriminating between stable and unstable (erosion, accretion) littoral zones of the Nile delta.Après une présentation des principales caractéristiques du littoral du delta du Nil et un rappel de quelques équations utilisées pour la simulation des profils d'équilibre des plages, l'auteur propose un système de deux relations empiriques qui ont permis de discriminer entre les zones littorales stables et instables (érosion, accumulation) du delta du Nil.Quelennec R. E. Rapport II.8 Intérêt de l'analyse des profils de plage pour l'étude de la dynamique sédimentaire littorale. Cas du littoral du delta du Nil. In: L'hydraulique et la maitrise du littoral. Problèmes côtiers posés par le mouvement des sédiments et la pollution. Dix-huitièmes journées de l'hydraulique. Marseille, 11-13 septembre 1984. Tome 2, 1984

Compte-rendu du séminaire national de Propriano sur «la gestion régionale des sédiments»

Quelennec R. E. Compte-rendu du séminaire national de Propriano sur «la gestion régionale des sédiments». In: Méditerranée, troisième série, tome 46, 3-4-1982. Développement et environnement dans la région Provence -Alpes Côte d'Azur. pp. 39-42

A new approach to modeling the flow curve of hot deformed austenite

A new, more physically realistic and practically useful model is presented for the simulation of high temperature austenite flow curves. It is an extension of our earlier empirical model based on the Avrami kinetics of dynamic recrystallization. In the new approach, the normalization parameter is expressed in terms of the fractional recrystallization and not the amount of softening. Compression experiments carried out on a Nb-modified plain carbon steel enable the simulated flow curves and progress of recrystallization predicted by the two models to be compared.© 2011 ISIJ

Many roads to flexibility. How large firms built autarchic regional production systems in France

This paper discusses the adjustment of large firms in France, in particular how they regionalized their production structures in the 1980s. Throughout the "Golden Age," large firms had geographically reorganized their activities: strategic planning remained in Paris, while the actual production was decentralized into the provinces, primarily to address cost and labour conflict issues. When the large firms faced a profitability crisis in the 1980s, and the traditional state-financed way out of the problems was no longer available, they saw in these proto-regional production systems a chance to become more competitive. They relied on the decentralization policies of the governments in the 1980s, and used the second-order effects of the new policies as a means to modernise their own operations

The formation of supersaturated solid solutions in Fe–Cu alloys deformed by high-pressure torsion

Fully dense bulk nanocomposites have been obtained by a novel two-step severe plastic deformation process in the immiscible Fe–Cu system. Elemental micrometer-sized Cu and Fe powders were first mixed in different compositions and subsequently high-pressure-torsion-consolidated and deformed in a two-step deformation process. Scanning electron microscopy, X-ray diffraction and atom probe investigations were performed to study the evolving far-from-equilibrium nanostructures which were observed at all compositions. For lower and higher Cu contents complete solid solutions of Cu in Fe and Fe in Cu, respectively, are obtained. In the near 50% regime a solid solution face-centred cubic and solid solution body-centred cubic nanograined composite has been formed. After an annealing treatment, these solid solutions decompose and form two-phase nanostructured Fe–Cu composites with a high hardness and an enhanced thermal stability. The grain size of the composites retained nanocrystalline up to high annealing temperatures