‘‘Amorphous’’ Ni60Nb40 has been prepared by mechanical alloying of elemental nickel and niobium powders in a laboratory ball mill in controlled environments. X-ray diffraction was used to follow the progress of the mechanical alloying which eventually produced ‘‘amorphous’’ diffraction patterns similar to those for liquid quenched amorphous Ni60Nb40. Crystallization behavior was measured by differential scanning calorimetry for the mechanically alloyed and liquid quenched material. The differences that were observed in this behavior, and in the products of crystallization, may be attributed to impurities (especially oxygen) introduced during mechanical alloying.

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Surface texture and interior residual stress variation induced by thickness of YBa2Cu3O7-δ thin films J. Appl. Phys. 112, 053903 (2012) New application of temperature-dependent modelling of high temperature superconductors: Quench propagation and pulse magnetization J. Appl. Phys. 112, 043912 (2012) Flux-pinning-induced interfacial shearing and transverse normal stress in a superconducting coated conductor long strip J. Appl. Phys. 112, 043908 (2012) High, magnetic field independent critical currents in (Ba,K)Fe2As2 crystals Appl. Phys. Lett. 101, 012601 (2012) Fabrication of binary FeSe superconducting wires by diffusion processThe semiempirical scaling law for flux pinning, Fp = AB ~2 b 1(1 -b )m has been tested for bronze process Nb 3 Sn conductors under uniaxial tension. The dependences of the bulk pinning force Fp on the upper critical field B e2 and the reduced field, b = B / B e2' were weakly affected by strain.However, the factor A, which depends on the number and strength of the pinning centers, and on the Ginzburg-Landau parameter K decreased by more than a factor of 20 when the compressive prestrain on the Nb 3 Sn was removed by application of external stress. The variations of Te and Be2 with strain suggest that the change in K is not sufficient to account for the change in A.Therefore, it is probable that strain induces microstructural changes which affect the number and/or strength of the pinning centers.

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