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Volume 35, Issue 5, May 2009
- LOW-TEMPERATURE PHYSICS OF PLASTICITY AND STRENGTH
35(2009); http://dx.doi.org/10.1063/1.3132752View Description Hide Description
The elastic and dissipative properties of nanostructured superconducting fiber composites Cu–32 vol.% Nb at frequencies of the order of are investigated in the temperature range . The composites, prepared by the method of intensive plastic deformation, consist of a fragmented copper matrix uniformly filled with niobium fibers having diameters of . It is found that the acoustic properties of the composite are mainly determined by the properties of the copper matrix. Near a relaxation peak of the internal friction is observed, with activational parameters close to those of the Bordoni peak in copper. Below the temperature dependence of the dynamic Young’s modulus is described by the thermally activated relaxation of two-level systems in a highly disordered medium. The influence of high-temperature annealing on the observed effects is investigated.