Real time in situ hard X-ray texture evolution during the annealing of rolled CuNi tapes

A new real time in-situ scattering method to study texture evolution kinetics is detailed. The technique is adapted from an existing set up used at the Institut Laue-Langevin neutron facility to check monochromators. It uses a white hard X-ray beam and works in transmission geometry. A 2D detector allows following of the recrystallization phenomena. A study of the annealing behavior of copper-nickel alloy rolled tapes, used as a substrate for high temperature superconductors, is presented

Thermal treatments for biaxially textured Cu-Ni alloys for YBCO coated conductors

We have studied the thermal treatments necessary to texture Cu-Ni alloys in view of applications as substrate for the YBCO coated conductors. Several alloy compositions chosen in order to avoid magnetism of the tapes have been elaborated by the rolling (RABiTS) method. Analyses of the texture as a function of annealing temperature have been done by X-ray and neutron diffractions, pole figures by EBSD and X-rays. The results show that the annealing temperature is dependant of the alloy composition and must be determined precisely for each composition. Good biaxial textures have been obtained on these cheap alloys

Industrial Cu-Ni alloys for HTS coated conductor tape

Copper rich Cu-Ni alloys have been textured with the RABiTS method in order to get non-magnetic and cost efficient substrates for coated conductor wires. The study is focused on two industrial compositions: Cu55Ni45 (Constantan) and Cu70Ni30. Studies on surface roughness have been done. The effects of annealing conditions (temperature and atmosphere) on the grain boundaries deepness were analyzed. Electrolytic polishing was also applied to improve the surface quality. RX pole figures and micro hardness measurements have been achieved on samples annealed up to 950°C. Attention has been paid to the rolling texture and to the annealing processes. The rolling texture has been found to be mainly copper-type (C, S and B contributions). Beginning of recrystallization occurred between 400°C and 600°C and stabilized between 900°C to 950°C, depending on the nickel content of the alloy. Finally both samples, rolled and annealed under the appropriate conditions, have been characterized. Pole figure measurements gave the global in plane and out of plane disorientations of our samples which are in-plane 7.4° and out-plane (RD) 4.3° for both samples. EBSD maps have shown the details of the distribution and have allowed us to quantify the ratio between cubic {100} and twined {122} orientations

Hyper texturation {100} <001> de substrats NiW pour câbles supraconducteurs

La seconde génération de rubans supraconducteurs utilisant une couche déposée et épitaxiée de supraconducteur YBa2Cu3O7-x (YBCO) est étudiée de façon intense (coated conductors). Une architecture simple à bas coût a été choisie, avec une seule couche tampon de La2Zr2O7 (LZO), épitaxiée sur un ruban de Ni95W5 texturé bi-axialement. L objectif de cette thèse était d identifier les paramètres pertinents du processus de texturation sur des rubans d alliage Ni95W5 laminés par APERAM à partir d une coulée industrielle et ceux contrôlant l épitaxie de la couche tampon de (LZO). Le rôle de la fonctionnalisation du substrat pour l épitaxie de cet oxyde sur la surface du métal a été en particulier étudié. Parallèlement, la faisabilité d un procédé de recuit de texturation et de fonctionnalisation du substrat métallique au défilé, en vue d un traitement continu pour un développement industriel, a été étudiée.The second generation of superconducting tapes using a deposited layer and epitaxialsuperconductor YBa2Cu3O7-x (YBCO) is studied intensively (coated conductors). A simple lowcostarchitecture was chosen, with one buffer layer La2Zr2O7 (LZO), epitaxially grown on aribbon of biaxially textured Ni95W5. The aim of this thesis was to identify the relevant processparameters texturing ribbons Ni95W5 alloy rolled by APERAM from an industrial casting, andthose controlling the epitaxial buffer layer (LZO). The role of the functionalization of thesubstrate for epitaxy of the oxide on the metal surface has been particularly studied. Meanwhile,the feasibility of an annealing process and functionalization texturing of the metal substrate rollto roll, in view of a continuous treatment for an industrial development, was studied.SAVOIE-SCD - Bib.électronique (730659901) / SudocGRENOBLE1/INP-Bib.électronique (384210012) / SudocGRENOBLE2/3-Bib.électronique (384219901) / SudocSudocFranceF

Characterization of the nanophase precipitation in a metastable beta titanium-based alloy by electrical resistivity, dilatometry and neutron diffraction

The metastable beta Ti-6Mo-5Ta-4Fe (wt.%) alloys was synthesized by cold crucible levitation melting and then quenched in water from the beta phase field. In order to investigate the transformation sequence upon heating, thermal analysis methods such as electrical resistivity, dilatometry and neutron thermodiffraction were employed. By these methods, the different temperatures of transition were detected and solute partitioning was oberved to the beta matrix during the omega and alpha nanophase precipitatio

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Thèse d'EtatL'apport de la spectrométrie neutronique à la compréhension des propriétés physiques des solides est essentiel pour toutes les questions relatives à la structure ou à la dynamique des matériaux. Les problèmes traités ces dernières années au Laboratoire de Chimie du Solide du CNRS et auxquels nous avons collaboré se rattachaient tous à l'aspect structural des solides et nécessitaient par conséquent un large emploi des techniques de diffraction. Ils ont été choisis en fonction des avantages que l'on pouvait tirer de l'utilisation de la diffraction des neutrons par rapport à la diffraction des rayons-X, avantages qui découlent des propriétés des neutrons eux-mêmes et qu'il convient de rappeler brièvement ici...non disponibl

Mise en place d'un procédé de fusion par défilement pour des rubans multifilamentaires supraconducteurs de Bi2Sr2Ca1Cu2O(8+x) à matrice argent

GRENOBLE1-BU Sciences (384212103) / SudocSudocFranceF

Elaboration de verres métalliques massifs à base de fer (caractérisation des propriétés magnétiques et structurales)

L'objectif de ce travail a été de développer un système d'alliages donnant des verres métalliques massifs possédant d'intéressantes propriétés magnétiques douces. Pour cela, nous avons tout d'abord étudié une famille d'alliages (Zr-Ti-Cu-Fe-Al) pauvres en fer mais s'appuyant sur des résultats très prometteurs au niveau de la capacité de vitrification. Nous nous sommes ensuite intéressés à la famille d'alliages à base de fer ((Fe,Co,Ni)-(Zr,Nb,)-B) qui présente les meilleurs résultats parus dans la littérature. La dernière partie de ce travail a été consacrée à l'étude de nouvelles compositions chimiques n'ayant fait l'objet d'aucune étude. S'inspirant, au départ, de la base Fe-Zr-B de la précédente famille, ces compositions s'en sont ensuite progressivement éloignées. Nous avons ainsi formé des échantillons non seulement sous forme de massifs mais également sous forme de rubans, que nous avons caractérisé aussi bien du point de vue structural que du point de vue magnétique.GRENOBLE1-BU Sciences (384212103) / SudocSudocFranceF

Phases formation during heating of Mg-Cu-Ag-Y bulk metallic glasses

International audienceDSC and in-situ neutron diffraction have been used in order to find the phases formed under various heating treatments in the vicinity of the glass transition for Mg-based bulk metallic glasses (BMG) The first phase to crystallize in the Mg(585)Cu(305)Y(11) alloy, when the sample is hold at T(g) + 20 K, is Mg(2)Cu and a nanocrystallized phase During continuous heating of the same sample, the main phases to crystallize are Mg(2)Cu, MgY and Cu(2)Y The alloy Mg(555)Cu(28.5)Ag(5)Y(11) has the best GFA parameters observed for Mg-based BMG (Delta T=54 degrees and gamma=0.415) and presents a single event for crystallization The phases formed by holding the sample at T(g) +20 K are the same than observed for the alloy without silver (Mg(2)Cu and nanophase) During continuous heating of this sample the same phases as previously observed appear but with Ag(3)Mg as extra phase. If ternary phases are present, they could correspond to tiny lines not refined, but they appear with a very low intensity Mg(2)Cu and Cu(2)Y produce the main intensity lines The appearance of nanocrystals during crystallization in the glass transition region could be at the origin of the plasticity observed in these alloy

Neutron in situ crystallization studies of Ti-based BMGs

International audienceThe phase evolution upon heating of Ti40Zr25Cu9Ni8Be18 BMG was investigated by in situ neutron diffraction studies and compared to Differential scanning calorimetry measurements performed at the same heating rate. When the experiment is performed at the constant speed of 2 K/min, the amorphous to crystallization process proceeds by two complicated crystallization reactions: firstly, the precipitation of a cubic Ti(Zr)Be-2 phase at 608K (a = 6.603 angstrom), this phase then disappears at 810 K, secondly, by the formation at 749K of two phases which have been determined by neutron diffraction to be a C14 hexagonal Laves phase and a big cube (Zr, Ti)(2)Ni phase. When the sample is heated at 2 K/min, then hold at T-g + 158 = 713K (before T-x2 = 749 K) the (Ti, Zr)Be-2 phase develops. After 60 min, the big cube phase starts to appear, an important amorphous bump being still present. These in situ diffraction experiments and the different phases formed are presented and discusse