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Fruhauf J.B.,Ecole Nationale Superieure des Mines de Saint - Etienne CMP | Roger J.,University Claude Bernard Lyon 1 | Dezellus O.,University Claude Bernard Lyon 1 | Gourdet S.,Airbus | And 5 more authors.
Materials Science and Engineering A | Year: 2012

Ti + 15%TiCp composites were prepared by three different powder metallurgy techniques: free sintering, HIPing and direct powder extrusion. The microstructures and textures were characterized by EBSD while the Ti/TiC reaction, which takes place during heat treatment, was characterized using X-ray diffraction and Rietveld analysis. The mechanical properties were obtained by the mean of tensile tests. TiC particles effectively reinforce the strength of the Ti matrix by at least 40% indicating the Ti/TiC reaction did not deteriorate the mechanical properties. The correlation between the microstructural features and the mechanical properties is discussed and the processes are compared. Direct powder extrusion was shown to be the most suitable process to obtain ductile composites (e{open}= 4.6%). © 2012 Elsevier B.V. Source


Lorong P.,Arts et Metiers ParisTech | Larue A.,Mecachrome | Perez Duarte A.,SNECMA
Advanced Materials Research | Year: 2011

The numerical simulation of machining process is a key factor in the control of parts machining process. Its development aims at improving the process reliability and reduces the time spent during the process planning stage. In this context, we use a specific time domain simulation allowing modeling the dynamics of a thin wall part turning operation. After having introduced the basics of the proposed approach we present a specific cutting test that has been designed to specifically measure and control the dynamics of the part and the cutting conditions of a finishing toolpath. The influences of the cutting speed and damping coefficient on the chatter occurrence are discussed. In order to better control the simulation uses, an analysis of the simulation parameters influences on the simulated results is proposed. © (2011) Trans Tech Publication. Source


Idarraga-Trujillo I.,CEA Saclay Nuclear Research Center | Le Flem M.,CEA Saclay Nuclear Research Center | Brachet J.-C.,CEA Saclay Nuclear Research Center | Le Saux M.,CEA Saclay Nuclear Research Center | And 8 more authors.
LWR Fuel Performance Meeting, Top Fuel 2013 | Year: 2013

Significant improvement in the safety of light water reactors should be achieved by the use of alternative cladding materials which are more robust than those currently serving as the first fuel containment barrier, in Loss of Coolant Accident (LOCA) and beyond-LOCA conditions. CEA is assessing the solution of a coated cladding aiming to protect the current zirconium alloy cladding from high temperature steam oxidation. The present paper particularly focuses on some recent results obtained at CEA on Cr coated Zircaloy-4 base materials that have experienced several hours exposure under steam at 1000°C ("post-breakaway" conditions for the bare Zircaloy-4 material). Source


Voisin T.,CNRS Toulouse Center for Materials Elaboration and Structural Studies | Monchoux J.-P.,CNRS Toulouse Center for Materials Elaboration and Structural Studies | Durand L.,CNRS Toulouse Center for Materials Elaboration and Structural Studies | Karnatak N.,Mecachrome | And 2 more authors.
Advanced Engineering Materials | Year: 2015

A study is conducted to show that the production of turbine blades in γ-TiAl alloys through spark plasma sintering (SPS) is a viable manufacturing route, by demonstrating that near-net shaping of γ-TiAl blades is successful, and by developing an alloy with balanced and outstanding mechanical properties at room and high temperatures in a single run and without subsequent thermal treatments. It is demonstrated that replacing nickel-based superalloys by such Intermetallic γ-TiAl alloys with high specific modulus and mechanical strength, combined with an exceptional resistance to oxidation, is an effective contribution to the development of lighter aircraft engines with high performance. Casting processes such as centrifugal cast have demonstrated that sound TiAl parts with a complex shape such as low-pressure turbine blades can be achieved. Source


Voisin T.,CNRS Toulouse Center for Materials Elaboration and Structural Studies | Durand L.,CNRS Toulouse Center for Materials Elaboration and Structural Studies | Karnatak N.,Mecachrome | Le Gallet S.,Laboratory Interdisciplinaire Carnot de Bourgogne | And 4 more authors.
Journal of Materials Processing Technology | Year: 2013

The determination and the homogeneity of the sample temperature during consolidation of powders by Spark Plasma Sintering (SPS) are addressed. Densifications were carried out in three different facilities differing by their constructors and their size. A structural transformation activated in a TiAl alloy was used as a marker of the sample temperature and finite element modeling were performed to evaluate the temperature at each point of the set-up. A good agreement between experimental and simulated data is exhibited. Alloys with identical microstructures were sintered and the homogeneity of the microstructure was better in the largest machines or when the sample was isolated by alumina disks. Large specimens with a diameter of 100 mm and a height of 60 mm were sintered, with the aim to achieve full densification and good microstructural control. On the basis of this temperature mastering, samples with complex shape were successfully densified. SEM post mortem observations confirmed the absence of porosities, and the expected microstructure as predicted by FEM calculations. © 2012 Elsevier B.V. Source

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