Effect of annealing and doping with Zr on the structure and properties of in situ Cu–Nb composite wire

Behavior of Nb and Cu–Nb Composites under Severe Plastic Deformation and Annealing

“…It is interesting to note that the same high level of microhardness (of about 2300 MPa) is obtained in the heavily cold-drawn to the same true strain CuNb composites consisting of Nb filaments in copper matrix. 66) In that case, the enhanced hardness and strength are attributed to specific deformation mechanisms in composites, where Nb filaments are refined to several nm in the transverse sections and acquire the ribbon-like shape. Regularities and specific features of the nanocrystalline structure formation in such composites are discussed in section 4.…”

Effects of size and geometry on the plasticity of high-strength copper/tantalum nanofilamentary conductors obtained by severe plastic deformation

“…Up to now, reinforced copper-based wires have shown the best compromise between these two criteria; in particular, the copper/niobium (Cu/Nb) system has been studied for decades since it has very good mechanical properties that are much better than rule-of-mixture (ROM) predictions when the size of the Nb filaments is reduced to the sub-micrometer range. It should be emphasized that two main fabrication routes have been studied: production of nanofilamentary Cu/Nb wires via severe plastic deformation (SPD) of: (i) arc-melted Cu-Nb ingots, initially consisting of a Cu matrix containing Nb dendrites, so-called ''in situ'' composites; and (ii) bulk Cu tubes and Nb rods, giving rise to a Cu matrix containing Nb continuous filaments, so-called ''continuous'' composites [2][3][4][5][6][7][8][9][10][11][12][13].…”

“…The same trend is expected using Fe as the reinforcing phase, since l Fe = 80 GPa (in this case, however, poorer electrical properties are expected due to the miscibility between Cu and Fe at high temperatures). In the literature, numerous studies of heavily deformed composites which consist of a face-centered cubic (fcc) matrix and a body-centered cubic (bcc) reinforcing phase are reported: ''in situ'' Cu/Nb [2][3][4][5][6][7][8][9][10][11][12], Cu/Ta [18,19] and Cu/Fe [20,21] systems. They all illustrate the considerable interest in Cu-based fcc/bcc composites because of the good combination of conductivity and strength.…”

Thermal stability of nanocrystalline structure in niobium processed by high pressure torsion at cryogenic temperatures

“…The value obtained is about twice as high as of niobium nanostructured at room temperature [13] or of high-strength heavily-drawn Cu-Nb composites [25,26] in which anomalously high strength is due to nano-scaled sizes of Nb filaments and interspaces between them in copper matrix [27].…”