No abstract

The X-ray tomography technique is employed to observe the effects of intermetallic compound particles on the nucleation and growth of hydrogen micropores at high temperatures in Al-Zn-Mg-Cu aluminum alloys. Hydrogen micropores are heterogeneously nucleated on particles during exposure at 748 K. Growth and coalescence of the hydrogen micropores are observed with increasing exposure time.Interactions between hydrogen micropores and particles have a significant influence on the growth and coalescence of hydrogen micro pores. The growth speed of hydrogen micropores, which are nucleated on spherical, small particles is faster than those on other nucleation sites.

Ni and Ni-based alloys have received considerable attention as the substrates for HTS coated conductors. A critical step in the successful fabrication of coated conductor composites on metal substrates is to produce cube texture by mechanical deformation using the rolling assisted biaxial textured substrate (RABiTS) approach. In this paper, we investigated the effects of mechanical deformation and heat treatment on the growth of texture in nickel and nickel–tungsten alloys with the objective of understanding mechanisms of mechanical texturing in coated conductor substrates. The results show that the sharpest cube texture is obtained by cold rolling nickel and nickel tungsten alloys in passes of less than 5% deformation followed by annealing at high temperature.

No abstract

SrTiO3 buffer layers have been deposited on rolled Ni substrates using metal organic deposition (MOD) for HTS-coated conductors. The MOD process is based on the formation of the SrTiO3 layer coated on the surface of a Ni substrate using dip-coating as well as spin-coating techniques from a solution-based precursor, which is prepared by dissolving strontium acetate and titanium (IV) butoxide in acetic acid and methanol. The films were annealed at 950 °C for 2 h under 5% H2–Ar gas flow. X-ray diffraction (XRD) shows that the buffer layers on the Ni tape are highly oriented. The pole figure indicates a single cube-on-cube texture in addition to SEM and AFM observations revealing a continuous, dense, smooth and crack-free microstructure for the coated buffer. These results offer the potential of further manufacturing coated conductors with high current density.