Department of Engineering Science and Technology, National Research Nuclear University “MEPhI” (Moscow Engineering-Physics Institute), Moscow, Russia:

Baryshev G. K., Post-Graduate Student, e-mail: gkbaryshev@mephi.ru

Biryukov A. P., Student
Surin V. I., Assistant Professor

“Russian superconductor” JSC, Moscow, Russia:

Pantsyrnyy V. I., Business Development Director

The first part of this work describes the methodology of analyses of properties of two-phase metallic-matrix Cu – Nb composites with the aid of structure-sensitive methods of electrophysical functional diagnostics. Electrical resistance, thermoelectric power and differential contact potential were sequentially measured by instrumentality of information measuring system. The results of measurement of electric resistance were analyzed from the position of integrated theory of conductivity. The mean calculated value of electric conductivity is 2.34 /μΩ·cm. There are presented the results of measurement of temperature dependence of differential thermoelectric power of Cu – Nb composite relatively to nickel, copper and chromium-nickel alloy (chromel). The absolute magnitude of differential thermoelectric power of Cu – Nb is more than two times lower than the corresponding values for industrial copper-constant and copper-copel thermocouples. There was made a comparison of the time dependence of differential contact potential difference for copper and Cu – Nb composite, measured in the points, corresponding to the middle of samples. The distinctive peculiarity of Cu – Nb composite testing became a remarkable increase of signal amplitude at the strain level of ~0.012. The experimental results prove the hypothesis of fractal character of mechanism of plastic strain at mesoscopic and macroscopic levels. There was estimated that inherent stress reticulation discontinuity (emerging at testing of Cu – Nb composite samples, which had the form of thin wires) is more than four times higher than the corresponding value for copper. With high value of Cu – Nb mechanical hardening, the stress relieving takes place with formation of surface deformation waves.

1. Kittel Ch. Vvedenie v fiziku tverdogo tela (Introduction into the solid-state physics). Translated from English. Under the editorship of A. A. Gusev. Moscow : Nauka, 1978.
2. Dulnev G. N., Zarichnyak Yu. P. Teploprovodnost smesey i kompozitsionnykh materialov (Thermal conductivity of mixtures and composite materials). Leningrad : Energiya, 1974. 264 p.
3. Gorinskiy S. G., Shabalin I. L., Beketov A. R., Podkovyrkin M. I., Kokorin A. F., Pakholkov V. V. Poroshkovaya metallurgiya — Powder metallurgy. 1980. No. 11. pp. 63–66.
4. Odelevskiy V. I. Zhurnal tekhnicheskoy fiziki — Journal of Applied Physics. 1951. Vol. 21. pp. 667–685.
5. Tablitsy fizicheskikh velichin : spravochnik (Tables of physical quantities: reference book). Under the editorship of I. K. Kikoin. Moscow : Atomizdat, 1976.
6. Surin V. I., Evstyukhin N. A. Elektrofizicheskie metody nerazrushayushchego kontrolya i issledovaniya reaktornykh materialov (Electrophysical methods of non-destructive control and researches of reactor materials). Moscow : MEPhI, 2008.
7. Surin V. I., Evstyukhin N. A., Cheburkov V. I. Osobennosti poverkhnostnoy deformatsii materialov (Peculiarities of surface deformation of materials). Sbornik nauchnykh trudov. Nauchnaya sessiya MIFI-2005 (Collection of scientific proceedings. Scientific symposium MEPhI-2005). Moscow : MEPhI, 2005. Vol. 9. pp. 90–91.
8. Persson B. N. J. Contact mechanics for randomly rough surfaces. Surface Science Reports. 2006. Vol. 61. pp. 201–227.
9. Rezvanian J., Brown C., Zikry M. A. et al. The role of creep in the time-dependent resistance of Ohmic gold contacts in radio frequency microelectromechanical system devices. Journal of applied physics. 2008. Vol. 104. pp. 024513-1–024513-5.
10. Kogut L., Komvopoulos K. Electrical contact resistance theory for conductive rough surfaces. Journal of applied physics. 2003. Vol. 94. pp. 3158–3162.