The workshop includes three wire-drawing machines, two heat-treatment furnaces, and the necessary equipment for microstructural, mechanical, and electrical characterization of the wires (Fig. 1).You can visit our workshop via the following link: https://storage.net-fs.com/hosting/6174450/16/, then navigate to the Coil Wires / Wire-Drawing Workshop section.

Figure 1: Photograph of (a) the wire-drawing bench (30-ton traction), (b) the wire-drawing bench (12-ton traction), (c) the bull-block (3-ton traction), (d) the static furnace (Tmax = 1150 °C), (e) the continuous furnace (2 m/h; Tmax = 1150 °C).

The design and fabrication of high-field non-destructive magnets pose a significant challenge for material development, as the component must meet both structural and functional requirements. Structurally, it requires high tensile strength to withstand Lorentz forces, while functionally, it must have low electrical resistivity to achieve the highest action integral and, consequently, the longest pulse duration.

LNCMI-Toulouse is involved in the development of several reinforced copper-based (Cu) conductors.

Cu-SS Macro-Composite Wires

This conductor features a simple and cost-effective manufacturing process. To produce it, a Cu rod is inserted into a stainless steel tube, and the entire assembly is co-drawn. When the stainless steel becomes too hard to allow further wire drawing under good conditions, a recrystallization heat treatment is applied to the conductor. The strain hardening resulting from the final annealing step optimizes the conductor’s properties.

With a Cu core ensuring very high electrical conductivity and a stainless steel sheath providing mechanical reinforcement, this conductor exhibits exceptional properties (Fig. 2). The ultimate tensile strength (UTS) of Cu-SS wires is approximately 1400 MPa, and their electrical resistivity is 0.45 µΩ·cm at 77 K. This material is used in the LNCMI’s 90 T coils and in the triple coil that enabled the European record of 98.8 T. It is possible to produce around 100 kg/year of this conductor.

Figure 2: Optical microscopy image of a cross-section of the Cu-SS conductor

SCIENTIFIC PUBLICATIONS RELATED TO CU-SS CONDUCTORS : [1, 2]

Nano-Filamentary Copper-Niobium (Cu-Nb) Composite Wires

Cu-Nb conductors are produced using the Accumulative Drawing and Bundling (ADB) process, which involves successive extrusion, wire drawing, and stacking steps. This results in the fabrication of a multi-filamentary composite wire with an architectured microstructure that is both nano-structured and multi-scale.

Different geometric configurations exist depending on the initial billet design: filamentary (Cu-Nb), co-cylindrical (Cu-Nb-Cu), and co-axial (Cu-Nb-Cu-Nb).
For co-cylindrical Cu-Nb-Cu wires, a Cu rod is inserted into a Nb tube. This assembly is then placed inside a Cu billet before undergoing hot extrusion (700°C), followed by wire drawing at room temperature. To optimize the filling factor during bundling, the wires are shaped using hexagonal dies. Eighty-five hexagonal wire segments are introduced into a new Cu billet before starting another deformation cycle. After n cycles, the conductor consists of 85ⁿ continuous and parallel Nb filaments.

Figure 3 presents SEM images of a co-cylindrical wire with three stacking stages. Nb fibers with a diameter smaller than 100 nm behave like whiskers, granting the composite wire exceptional mechanical properties. A 0.3 mm diameter wire can achieve an UTS of up to 1.9 GPa. Since the Cu matrix remains pure throughout the fabrication process, the composite wire maintains low resistivity (0.6 µΩ·cm at 77 K).

Figure 3: SEM images of a Cu-Nb-Cu composite wire at different magnifications, showing the various stacking levels

SCIENTIFIC PUBLICATIONS RELATED TO CU-Nb CONDUCTORS : [1, 3, 4, 5, 6, 7, 8, 9, 10, 14, 15, 18]

Copper-Carbon Nanotube (CNT-Cu) Composite Wires

Copper wires reinforced with carbon nanotubes (CNT-Cu) are the result of an initial collaboration between CIRIMAT (Toulouse) and LNCMI. They are produced using an innovative process, first developed for pure Cu, combining powder metallurgy, cylinder consolidation via Spark Plasma Sintering (SPS), and room-temperature wire drawing.

A powder mixture of Cu and carbon nanotubes (CNTs) (Fig. 4a) is consolidated through SPS . SPS was chosen because this sintering technique allows consolidation at lower temperatures and for shorter durations (≤ 25 min) than other methods, significantly limiting Cu grain growth. The grain size of Cu in SPS cylinders remains similar to that in the initial powders (0.5–1 μm), which is up to 10 times smaller than that found in Cu wire precursors obtained by melting/solidification.

After drawing, the microstructure of 0.5 mm diameter wires consists of highly elongated grains (several micrometers long) in the drawing direction, with a width between 100 and 600 nm (Fig. 4b). The combination of powder metallurgy, SPS consolidation, and wire drawing allows for the introduction of up to 1 vol.% carbon into the Cu matrix while maintaining very low electrical resistivity (0.35 μΩ·cm at 77 K) and achieving a high UTS of approximately 800 MPa. The reinforcement of these wires is attributed to the nano-structured Cu matrix and the longitudinal alignment of CNTs during wire drawing, which optimally orients them along the wire axis.

Figure 4: (a) SEM image of the Cu-CNT composite powder and (b) TEM image of a longitudinal section of a 0.5 mm diameter Cu-CNT wire.

SCIENTIFIC PUBLICATIONS RELATED TO CNT-CU CONDUCTORS: [11, 12, 13, 16]

Copper-silver (Ag-Cu) Composite Wires

These Ag-Cu composite wires are also produced through a combination of powder metallurgy, SPS sintering, and wire drawing.

The composite powders (Fig. 5a), with low silver content (< 10 vol.% Ag), are prepared by dispersing Ag microfibers (diameter: 200 nm, length: 30 μm)—synthesized at CIRIMAT—into commercial spherical Cu powder (diameter: 0.5–1 μm). These powders are then consolidated into bars via SPS (Fig. 5b). The bars can be drawn without breaking to produce thin wires (diameter: 1–0.2 mm) with an ultrafine Cu grain structure (200–400 nm), elongated over several micrometers in the drawing direction. The Ag microfibers are dispersed along Cu grain boundaries.

Measurements of electrical resistivity and UTS (at 293 K and 77 K) show that wires containing only 1 vol.% Ag offer the best strength/resistivity trade-off (1100 MPa / 0.49 μΩ·cm at 77 K). The formation of a Cu/Ag alloy during SPS sintering increases electrical resistivity and should be avoided. A Cu matrix with a bimodal grain size distribution helps to reduce resistivity while maintaining high tensile strength (1080 MPa / 0.45 μΩ·cm at 77 K). These Ag-Cu nanocomposite wires achieve a UTS comparable to Cu/Ag alloy wires (produced by melting and solidification) containing ~20 times more Ag but exhibit ~1.5 times lower electrical resistivity.

Figure 5: (a) SEM image of the Cu-Ag composite powder and (b) SEM image of a cross-section of an 8 mm diameter Ag-Cu bar (Gray: Cu; White: Ag; Black: Porosity).

SCIENTIFIC PUBLICATIONS RELATED TO AG-CU CONDUCTORS: [17, 19, 20, 21, 23]

Copper/Silver (Cu/Ag) Alloy Wires

The Cold-Spray (CS) process is an innovative method for wire manufacturing, combining powder metallurgy, CS deposition, and wire drawing. This approach is the result of a collaboration between LNCMI-T&G and LERMPS (UTBM-Belfort).

In the CS treatment, Cu/Ag spherical powder particles (d₁₀ = 12 µm, d₅₀ = 20 µm, d₉₀ = 37 µm) are accelerated to high velocities in a helium gas flow and bonded to the substrate upon impact through plastic deformation and localized phenomena such as dynamic recrystallization. The resulting Cu/Ag CS deposit serves as a precursor for wire drawing.

The Cu/Ag wires produced through this method exhibit very high tensile strength (1660 MPa at 77 K) and low electrical resistivity (1.05 μΩ·cm at 77 K). Microstructural studies using STEM reveal the reasons behind this exceptional mechanical strength compared to materials produced via other methods. Due to the high velocity of deposited particles, the CS process leads to high initial strain rates and unique microstructural characteristics.

To further reduce the electrical resistivity of CS-derived wires, an alternative composite approach is under investigation.

Figure 6: (a) STEM HAADF image of a cross-section and (b) STEM HAADF image of a longitudinal section of a 0.5 mm diameter Cu/Ag wire.

SCIENTIFIC PUBLICATIONS RELATED TO CU/AG CONDUCTORS: [22]

Tensile Strength and Electrical Resistivity of Reinforced Conductors developed at LNCMI

​

Figure 7: Tensile Strength vs. Electrical Resistivity at 77 K for Cu OFHC, Cu-CNT wires, Cu-Ag SPS wires, Cu/Ag CS wires, Cu-SS wires and Cu-Nb wires

Doctoral thesis

Dupouy 1995, Thilly-2000, Vidal-2006, Dubois-2010, Arnaud-2015, Tardieu-2020

Patent

• L. Thilly, F. Lecouturier, J-B. Dubois, N. Ferreira, P-O. Renault, P. Olier, Composite conductive cable comprising nanotubes and nanofibers, coaxial microstructure including a copper matrix and said nanotubes and nanofibers and method for manufacturing said microstructure.
French patent granted 13 march 2015, FR2968823 (B1)
European patent granted 4 may 2016, n° 2 652 747
US patent granted 12 july 2016, n° 9 390 839 (B2)

• F. Lecouturier, C. Laurent, S. Tardieu, D. Mesguich, A. Lonjon, N. Ferreira, G. Chevallier, C. Estournes, Copper-silver composite material.
French patent granted 14 may 2021, FR3084376 (B1)
European patent granted 22 may 2024, EP3830309 (B1)

Publications

[1] Established and emerging materials for use as high-field magnet conductors; K. Spencer, F. Lecouturier, L. Thilly and J. D. Embury, Advanced Engineering Materials (2004) 6 n°5 290-297.
[2] Identification of aging mechanisms for non destructive pulsed magnets operating in the 60T range; J. Billette, F. Lecouturier, O. Portugall, IEEE Transactions on Applied Superconductivity (2004) vol 14 n°2, 1237-1240.
[3] Effects of size and geometry on the plasticity of high strength copper/tantalum nanofilamentary conductors obtained by severe plastic deformation, V. Vidal, L. Thilly, F. Lecouturier, P.-O. Renault, Acta Materiala Vol 54 Iss 4 (2006) pp 1063-1075.
[4] Cu nanowhiskers embedded in Nb nanotubes inside a multiscale Cu matrix: the way to reach extreme mechanical properties in high strength conductors, V. Vidal, L. Thilly, F. Lecouturier, P.-O. Renault, Scripta Materiala vol 57 (3) (2007) 245-248.
[5] Plasticity of nanostructured Cu-Nb-based wires: strengthening mechanisms revealed by in-situ deformation under neutrons, V. Vidal, L. Thilly, S. Van Petegem, U. Stuhr, F. Lecouturier, P.-O. Renault and H. Van Swygenhoven, Scripta Mat, vol 60 (2009) 171-174.
[6] A new criterion for the elasto-plastic transition in nanomaterials: application to size and composite effects on Cu-Nb nanocomposite wires; L. Thilly, S. Van Petegem, P.O Renault, F. Lecouturier, V. Vidal, B. Schmitt, H. Van Swygenhoven, Acta Mat vol 57 (2009) 3157-3169.
[7] Thermal stability of nanocomposite metals: In situ observation of anomalous residual stresses relaxation during annealing under synchrotron radiation; J.B. Dubois, L. Thilly, P.O. Renault, F. Lecouturier, M. Di Michiel, Acta Materialia 58 (2010) 6504–6512.
[8] Metallic composites processed via extreme deformation: Toward the limits of strength in bulk materials; D. Raabe, P.P. Choi, Y. Li, A. Kostka, X. Sauvage, F. Lecouturier, K. Hono, R. Kirchheim, R. Pippan , D. Embury, MRS Bulletin 35 (12) (2010) 982-991.
[9] Microstructure and texture of copper/niobium composites processed by ECAE; E. Buet, J.B. Dubois, P. Olier, L. Thilly, F.Lecouturier, P.O. Renault, INTERNATIONAL JOURNAL OF MATERIAL FORMING 5 (2) (2012) 121-127.
[10] Cu-Nb nanocomposite wires processed by severe plastic deformation: effects of the multi-scale microstructure and internal stresses on elastic-plastic properties; J.B. Dubois, L. Thilly, P.O. Renault, F. Lecouturier, Advanced Engineering Materials, 14 (11) (2012) 998–1003.
[11] Dog-bone copper specimens prepared by one-step spark plasma sintering; C. Arnaud, C. Manière, G. Chevallier, C. Estournès, R. Mainguy, F. Lecouturier, D. Mesguich, A. Weibel, L. Durand, C. Laurent, Journal of Material Science (2015) 50:7364–7373. https://doi.org/10.1007/s10853-015-9293-5
[12] High strength – high conductivity nanostructured copper wires prepared by spark plasma sintering and room-temperature severe plastic deformation; C. Arnaud, F. Lecouturier, D. Mesguich, N. Ferreira, G. Chevallier , C. Estournès, A. Weibel, A. Peigney, Ch. Laurent, Materials Science and Engineering A – Structural Materials Properties Microstructure And Processing, 649 (2016) 209-213. http://dx.doi.org/10.1016/j.msea.2015.09.122
[13] High strength – high conductivity double-walled carbon nanotube – copper composite wires; C. Arnaud, F. Lecouturier, D. Mesguich, N. Ferreira, G. Chevallier, C. Estournès, A. Weibel, C. Laurent, Carbon 96 (2016) 212-215. doi:10.1016/j.carbon.2015.09.061
[14] Multiscale modeling of the elastic behavior of architectured and nanostructured Cu-Nb composite wires; T. Gu, O. Castelnau, S. Forest, E. Hervé-Luanco, F. Lecouturier, H. Proudhon, L. Thilly, International Journal of Solids and Structures 121 (2017) 148-162. https://doi.org/10.1016/j.ijsolstr.2017.05.022
[15] Multiscale modeling of the anisotropic electrical conductivity of architectured and structured Cu-Nb composite wires and experimental comparison comparison; T. Gu, J.R. Medy, F. Volpi, O. Castelnau, S. Forest, E. Herve-Luanco, F. Lecouturier, H. Proudhon, P.O. Renault, L. Thilly; Acta Materialia (2017) Vol 141 131-141. http://dx.doi.org/10.1016/j.actamat.2017.08.066
[16] High strength – high conductivity carbon nanotube-copper wires with bimodal grain size distribution by Spark Plasma Sintering and wire-drawing; D. Mesguich, C. Arnaud, F. Lecouturier, N. Ferreira, G. Chevallier, C. Estournès, A. Weibel, C. Josse, C. Laurent, Scripta Mat 137 (2017) 78-82. http://dx.doi.org/10.1016/j.scriptamat.2017.05.008
[17] Nanostructured 1% silver-copper composite wires with a high tensile strength and a high electrical conductivity; S. Tardieu, D. Mesguich, A. Lonjon, F. Lecouturier, N. Ferreira, G. Chevallier, A. Proietti, C. Estournès, C. Laurent, Materials Science and Engineering: A 761, 138048 (2019). https://doi.org/10.1016/j.msea.2019.138048
[18] Multiscale modeling of the elasto-plastic behavior of architectured and nanostructured Cu-Nb composite wires and comparison with neutron diffraction experiments; T. Gu, J.-R. Medy, V. Klosek, O. Castelnau, S.Forest, E. Hervé-Luanco, F. Lecouturier-Dupouy, H.Proudhon, P.-O. Renault, L. Thilly, P. Villechaise, International Journal of Plasticity 122 (2019) 1-30. https://doi.org/10.1016/j.ijplas.2019.04.011
[19] High Strength-High Conductivity Silver Nanowire-Copper Composite Wires by Spark Plasma Sintering and Wire-Drawing for Non-Destructive Pulsed Fields, S. Tardieu, D. Mesguich, A. Lonjon, F. Lecouturier-Dupouy, N. Ferreira, G. Chevallier, A. Proietti, C. Estournès, C. Laurent, IEEE Transactions on Applied Superconductivity, Vol. 30 (4), 2020, 6900304. https://doi.org/10.1109/TASC.2020.2974420
[20] Influence of alloying on the tensile strength and electrical resistivity of silver nanowire – copper composites macroscopic wires, S. Tardieu, D. Mesguich, A. Lonjon, F. Lecouturier-Dupouy, N. Ferreira, G. Chevallier, A. Proietti, C. Estournès, C. Laurent, Journal of Materials Science, Vol. 56, 2021, 4884–4895. https://doi.org/10.1007/s10853-020-05556-9
[21] Influence of bimodal copper grain size distribution on electrical resistivity and tensile strength of silver – copper composite wires, S. Tardieu, D. Mesguich, A. Lonjon, F. Lecouturier-Dupouy, N. Ferreira, G. Chevallier, A. Proietti, C. Estournès, C. Laurent, Materials Today Communications, Vol. 37, 2023, 107403. https://doi.org/10.1016/j.mtcomm.2023.107403
[22] High-Strength Copper/Silver Alloys Processed by Cold Spraying for DC and Pulsed High Magnetic Fields, S. Tardieu, H. Idrir, C. Verdy, O. Jay, N. Ferreira, F. Debray, A. Joulain, C. Tromas, L. Thilly, F. Lecouturier-Dupouy, Magnetochemistry,Vol.10(3), 2024, 15. https://doi.org/10.3390/magnetochemistry10030015
[23] Scale-up of silver – copper composite wires by spark plasma sintering and room temperature wire-drawing for use in 100 T triple coil at LNCMI, S. Tardieu, J. Béard, D. Mesguich, A. Lonjon, N. Ferreira, G. Chevallier, C. Estournès, C. Laurent, F. Lecouturier-Dupouy, IEEE Transactions on Applied Superconductivity, Vol. 34(5), 2024, 1-4. https://doi.org/10.1109/TASC.2024.3369011

The Laboratoire National des Champs Magnétiques Intenses (LNCMI) in Grenoble is one of the CNRS’s major research facilities. It provides the scientific community with access to the highest possible magnetic fields. The method used to produce high magnetic fields is to follow Ampère’s law: circulate an electric current.

High-field magnets are made up of concentric coils, Figure 1 and Figure 2. The current injected into these coils can reach up to 33,000 A. The conducting materials are then subjected to Lorentz stresses and Joule heating, which must be removed by continuous cooling to produce a stable magnetic field. High-field magnets therefore require materials with high mechanical strength and electrical conductivity under high-temperature conditions. The most conventional base material for this application is copper, thanks to its high electrical conductivity (58 MS/m at 20°C for an annealed pure copper wire, International Annealed Copper Standard [1]). However, the mechanical strength of pure copper is rather mediocre, at 365 MPa for yield strength [1]. It is therefore essential to improve its strength in order to produce high magnetic fields. There are two common methods for achieving this. There are two common methods of achieving this. The first is the use of alloying elements to achieve one or more hardening mechanisms, such as solid solution hardening, precipitation hardening or second-phase hardening. The second is the use of a thermomechanical process to modify the microstructure appropriately. However, even low levels of impurities can lead to a sharp drop in copper conductivity [2]. Consequently, the alloying element and its quantity must be chosen with care.

Figure 1: The different coils used

Figure 2: View 3/4 of a complete insert with 14 coils

The most common alloying element currently used at LNCMI-G is silver. As a pure metal, silver has a high conductivity (around 61.5 MS/m) and is known for its ability to improve the mechanical properties of copper via a discontinuous precipitation mechanism [3]. However, a high element content leads to a sharp decrease in the material’s conductivity [4]. Consequently, we need to measure the impact of the silver proportions studied on the final conductivity of the material.

In addition to this composition selection, thermomechanical treatments can be used in the manufacturing process to increase the material’s mechanical properties through plastic deformation. Various processes can be used, such as cold rolling, stretching and equal-area bent extrusion. However, these processes do not meet the need for a large, reproducible material for the intended application. It was therefore decided to use the cold spray (CS) process to produce large structural materials, thanks to its low processing temperature.

Raw material: high-quality powder

Cold spraying involves projecting powder particles onto a substrate at high speed. The size and shape of the particles will have a major impact on the quality of the deposit. The development of this raw material is carried out in collaboration with the ICB-UTBM laboratory in Belfort. They are equipped with an atomization tower enabling batches of up to 50 kg to be produced, Figure 3.

Atomization involves spraying a stream of molten material from a mixing crucible into fine particles. A high-pressure gas jet disrupts the flow of molten metal, enabling it to be atomized, Figure 4. The particles then solidify as they fall into the atomizing tower. The installation at ICB-UTBM is equipped with an atomizing nozzle with a “Laval” profile, enabling laminar gas flow. This allows better control of the particle size generated. The particle size distribution of the powder produced is thus narrower, and it is possible to aim for a smaller average diameter.

Figure 3: Photo of the atomization tower at UTBM

Figure 4: Illustration of the atomization process [5]

The criteria determining the quality of the powder we use are as follows:

• • homogeneity of composition
  • particle morphology
  • presence of satellites
  • size distribution
  • oxygen content

In our production processes, we use spheroidal powder with few satellites, Figure 5. The particle size distribution is between 15 and 50 µm in diameter, and the oxygen content must be less than 140 ppm.

Figure 5: SEM image of CuAg5.5pds.% powder

Cold spray process
Cold spraying is based on a velocity interval in which the particles launched will agglomerate on a given substrate. The particles are accelerated to super-sonic velocities using a Laval-type nozzle. A powder supply tube is located in the middle of the carrier gas upstream of this nozzle, Figure 6. The carrier gas is heated to increase particle velocity. Indeed, the expansion of the gas as it passes through the throat of this nozzle makes it possible to achieve these high velocities.

Figure 6: Illustration of the cold spray process [6]

During spraying, the temperature of the particles remains below their melting point, thus maintaining the initial microstructure. In addition, during impact, the particles undergo plastic deformation, which refines the microstructure in the impact zone, Figure 7 and Figure 8.

Figure 7: Illustration of particle deformation on impact [7]

Figure 8: Optical microscopy of a CuAg5.5pds.% deposit after etching

As oxygen has a significant impact on copper resistivity [5], its proportion must be controlled throughout the manufacturing process. For this reason, the ICB-UTBM facility is equipped with a helium tank, Figure 9 and Figure 10. In addition to increasing achievable speeds, the use of this gas keeps the oxygen content of the final product virtually identical to that of the powder.

Figure 9: Photo of the installation at ICB-UTBM

Figure 10: Photo of deposition nozzle inside the tank

Cold spraying of copper-silver powder with helium achieves:

• • a high deposition rate
  • a low porosity rate
  • a low oxygen content
  • a high mechanical strength value
  • good electrical conductivity

Materials obtained and use
After spraying, the material obtained has a high internal stress rate; an annealing heat treatment is then applied. Depending on the temperature selected and the duration of this treatment, the material’s mechanical and electrical properties can be adjusted, Figure 11. Depending on the coil’s position in the final assembly, different stresses will be applied. It is then possible to adjust the manufacturing cycle for the final use.

Figure 11: Stress versus conductivity for various materials done by CS

The use of the cold spraying process to produce coils for high-field magnets has enabled us to develop materials that meet the constraints of use. Coil reliability has been improved, enabling high field strengths to be achieved with good magnetic field stability.

[1] United States. National Bureau of Standards, Copper wire tables, Washington Govt. Print. Off, 1914. http://archive.org/details/copperwiretables31unituoft (accessed March 27, 2025).
[2] J.R. Davis, ASM International, eds., Copper and copper alloys, 1. printing, ASM International, Materials Park, Ohio, 2001.
[3] D. Hamana, M. Hachouf, L. Boumaza, Z.E.A. Biskri, Precipitation Kinetics and Mechanism in Cu-7 wt% Ag Alloy, Materials Sciences and Applications 02 (2011) 899. https://doi.org/10.4236/msa.2011.27120.
[4] G. Ghosh, J. Miyake, M.E. Fine, The systems-based design of high-strength, high-conductivity alloys, JOM 49 (1997) 56–60. https://doi.org/10.1007/BF02914659.
[5] T. Laag, Opportunities of Powder Metallurgical Processing of Palladium and Platinum Jewellery Alloys, (2019). https://www.academia.edu/68484491/Opportunities_of_Powder_Metallurgical_Processing_of_Palladium_and_Platinum_Jewellery_Alloys (accessed March 27, 2025).
[6] F. Raletz, Contribution au développement d’un procédé de projection dynamique à froid (P. D. F. ) pour la réalisation de dépôts de nickel, thesis, Limoges, 2005. https://theses.fr/2005LIMO0024 (accessed March 27, 2025).
[7] J. Villafuerte, ed., Modern Cold Spray: Materials, Process, and Applications, Springer International Publishing, Cham, 2015. https://doi.org/10.1007/978-3-319-16772-5.

High-Strength Copper/Silver Alloys Processed by Cold Spraying for DC and Pulsed High Magnetic Fields
S. Tardieu, H. Idrir, C. Verdy, O. Jay, F. Debray, A. Joulain, C.Tromas, L.Thilly, F. Lecouturier-Dupouy
Magnetochemistry 2024, 10(3), 1, 10.3390/magnetochemistry10030015

Scale-up of silver – copper composite wires by spark plasma sintering and room temperature wire-drawing for use in 100 T triple coil at LNCMI
S. Tardieu, J. Béard, D. Mesguich, A. Lonjon, G. Chevallier, C. Estournès, Ch. Laurent, F. Lecouturier-Dupouy
IEEE Transactions on Applied Superconductivity, vol 34, iss 5 (2024), 10.1109/TASC.2024.3369011

Influence of bimodal copper grain size distribution on electrical resistivity and tensile strength of silver – copper composite wires
S. Tardieu, D. Mesguich, A. Lonjon, F. Lecouturier-Dupouy, N. Ferreira, G. Chevallier, A. Proietti, C. Estournès, C. Laurent
Materials Today Communications, vol 37, December 2023, 107403, 10.1016/j.mtcomm.2023.107403

Influence of alloying on the tensile strength and electrical resistivity of silver nanowire: copper composites macroscopic wires
S. Tardieu, D. Mesguich, A. Lonjon, F. Lecouturier-Dupouy, N. Ferreira, G. Chevallier, A. Proietti, C. Estournès, C. Laurent
Journal of Materials Science, 56, pages4884–4895(2021), 10.1007/s10853-020-05556-9

Multiscale modeling of the elasto-plastic behavior of architectured and nanostructured Cu-Nb composite wires and comparison with neutron diffraction experiments
T. Gu, J.-R. Medy, V. Klosek, O. Castelnau, S. Forest, E. Herve-Luanco, F. Lecouturier-Dupouy, H. Proudhon, P.-O. Renault, L. Thilly
International Journal of Plasticity, 122 (2019) 1-30, 10.1016/j.ijplas.2019.04.011

Multiscale modeling of the anisotropic electrical conductivity of architectured and structured Cu-Nb composite wires and experimental comparison
T. Gu, J.R. Medy, F. Volpi, O. Castelnau, S. Forest, E. Herve-Luanco, F. Lecouturier, H. Proudhon, P.O. Renault, L. Thilly
Acta Materialia vol 141 December 2017 131-141, 10.1016/j.actamat.2017.08.066

High strength – high conductivity carbon nanotube-copper wires with bimodal grain size distribution by Spark Plasma Sintering and wire-drawing
D. Mesguich, C. Arnaud, F. Lecouturier, N. Ferreira, G. Chevallier, C. Estournès, A. Weibel, C. Josse, C. Laurent
Scripta Materiala 137 (2017) 78-82, 10.1016/j.scriptamat.2017.05.008

High strength – high conductivity double-walled carbon nanotube – copper composite wires
C. Arnaud, F. Lecouturier, D. Mesguich, N. Ferreira, G. Chevallier, C. Estournès, A.Weibel, C. Laurent
Carbon 96 (2016) 212-215, 10.1016/j.carbon.2015.09.061

Cu-Nb nanocomposite wires processed by severe plastic deformation: effects of the multi-scale microstructure and internal stresses on elastic-plastic properties
J.B. Dubois, L. Thilly, P.O. Renault, F. Lecouturier
Advanced Engineering Materials, vol 14, iss 11, 998–1003, November 2012

Metallic composites processed via extreme deformation: Toward the limits of strength in bulk materials
D. Raabe, P-P.Choi , Y. Li, A. Kostka, X. Sauvage, F. Lecouturier, K. Hono, R. Kirchheim, R. Pippan , D. Embury
MRS Bulletin, vol 35, n° 12 (December 2010) pp. 982-991

Thermal stability of nanocomposite metals: In situ observation of anomalous residual stresses relaxation during annealing under synchrotron radiation
J.B. Dubois, L. Thilly, P.O. Renault, F. Lecouturier, M. Di Michiel
Acta Materialia 58 (2010) 6504–6512

A new criterion for the elasto-plastic transition in nanomaterials: application to size and composite effects on Cu-Nb nanocomposite wires
L. Thilly, S. Van Petegem, P-O. Renault, F. Lecouturier, V. Vidal, B. Schmitt, H. Van Swygenhoven
Acta Materiala, vol 57 (2009) 3157-3169

Plasticity of nanostructured Cu-Nb-based wires: strengthening mechanisms revealed by in-situ deformation under neutrons
V. Vidal, L. Thilly, S. Van Petegem, U. Stuhr, F. Lecouturier, P.-O. Renault and H. Van Swygenhoven
Scripta Materiala, vol 60 (2009) 171-174

Cu nanowhiskers embedded in Nb nanotubes inside a multiscale Cu matrix: the way to reach extreme mechanical properties in high strength conductors
V. Vidal, L. Thilly, F. Lecouturier, P.-O. Renault
Scripta Materiala, vol 57 (3) (2007) 245-248

Size effects on the magnetic properties of Cu-Nb nanofilamentary processed by severe plastic deformation
M. J. R. Sandim, D. Stamopoulos, H. R. Z. Sandim, L. Ghivelder, L. Thilly, V. Vidal, F. Lecouturier, D. Raabe
Superconducting Science and Technology 19 (2006) 1233-1239

Plasticity of multi-scale nanofilamentary Cu/Nb composite wire during in-situ neutron diffraction: co-deformation and size effect
L. Thilly, P.O. Renault, V. Vidal, F. Lecouturier, S. Van Petegem, U. Stuhr and H. Van Swygenhoven
Applied. Physics. Letters. 88, 191906 (2006)

Effects of size and geometry on the plasticity of high strength copper/tantalum nanofilamentary conductors obtained by severe plastic deformation
V. Vidal, L. Thilly, F. Lecouturier, P.-O. Renault
Acta Materiala vol 54 iss 4 (2006) pp 1063-1075

Identification of aging mechanisms for non destructive pulsed magnets operating in the 60T range
J. Billette, F. Lecouturier, O. Portugall
IEEE Transactions on Applied Superconductivity (2004), vol 14, n° 2, 1237-1240

Established and emerging materials for use as high-field magnet conductors
K. Spencer, F. Lecouturier, L. Thilly and J. D. Embury
Advanced Engineering Materials (2004), 6, n°5, 290-297

Size-induced enhanced mechanical properties of nanocomposite copper/niobium wires: nanoindentation study
L. Thilly, F. Lecouturier, J. Von Stebut
Acta Materiala, vol 50, iss 20, 3 December 2002, 5049-5065

High strength materials: in situ investigations of dislocations behaviour in Cu/Nb multifilamentary nanostructured composites
L. Thilly, M. Véron, O. Ludwig, F. Lecouturier, J.P. Peyrade, S. Askénazy,
Philosophical Magazine A , 2002, vol 82, n°5, 925-942

Phase transformation in nanostructured materials produced under heavy plastic deformation
X. Sauvage, L. Thilly, F. Lecouturier, A. Guillet, K. Hono, D. Blavette
Advances-in-Mechanical-Behaviour,Plasticity and Damage. 2000. 847-852 vol 2

Axial and radial interface instabilities of copper/tantalum cylindrical conductors
J. Colin, L. Thilly, F. Lecouturier, J.P. Peyrade, J. Grilhé, S. Askénazy
Acta Materiala 47(9), 2761, 1999

Microstructural characterization of high strength and high conductivity nanocomposite wires
F. Dupouy, E. Snoeck, M.J. Casanove, C. Roucau, J.P. Peyrade, S. Askénazy
Scripta Materiala, vol 34, n°7, 1067-1073, 1996

Composite conductors for high pulsed magnetic fields
F. Dupouy, S. Askénazy, J.P. Peyrade, D. Legat
Physica B 211 (1995) 43-45