Biaxially textured constantan alloy (Cu 55 wt percent, Ni 44 wt percent, Mn 1 wt percent) substrates for Yba_2Cu_3O_(1-x) coated conductors

摘要

Commercially available constantan alloy rods (nominal composition Cu55-Ni44-Mnl wt percent) have been thermo-mechanically processed to develop biaxially textured substrates. It was found that the (001) recrystallization cube texture percentage could be increased from 72 percent to nearly 100 percent as the annealing temperature of the rolled substrates was increased from 750 to 1200 deg C. A full width half maximum (FWHM) of 6.5 deg in (111) phi scans and an FWHM of 4.9 deg in (100) omega scans were observed in the substrates annealed at 1200 deg C for 2 h. These substrates were found to have a Curie temperature of 35 K and so were paramagnetic at 77 K and ferromagnetic at 5 K with a saturation magnetization that is 2.5 times less than that of Ni-5 at. percent W substrates. Yield strengths of highly textured constantan substrates were found to be 1.5 times that of textured pure Ni substrates at room temperature.