Biaxially textured constantan alloy (Cu 55 wt%, Ni 44 wt%, Mn 1 wt%) substrates for YBa₂Cu₃O_7−xcoated conductors

Abstract

Commercially available constantan alloy rods (nominal composition Cu55-Ni44-Mn1 wt%) 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% to nearly 100% as the annealing temperature of the rolled substrates was increased from 750 to 1200 • C. A full width half maximum (FWHM) of 6.5 • in (111) phi scans and an FWHM of 4.9 • in (100) omega scans were observed in the substrates annealed at 1200 • 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.% 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.

Tensile strengths and Young’s modulus of thin copper and copper-nickel (CuNi44) substrates

“…Biaxial textured constantan (CuNi) alloys were also investigated as substrates for YBa 2 Cu 3 O 7-x coated conductors [10][11][12]. Those CuNi alloys have lower saturation magnetization than Ni with 5 at.% W, and higher yield strengths than pure Ni substrates.…”

Development and characterization of cube-textured Ni–Cu–Co substrates for YBCO-coated conductors

“…The development of cube orientation in Ni and Ni-W is relatively easy, and a sharp texture can be obtained at temperatures as low as 300°C and 800°C, respectively [30,31], whereas higher temperatures are required in order to obtain similar results in Ni-Cu-based alloys, as already pointed out by Varanasi et al [19]. In fact Ni-Cu-Co alloys exhibit an area fraction of cube grains >95% when annealed at 1050°C.…”

“…Though it can be textured relatively well, there are no quantitative results on the superconducting properties of YBCO film grown on such a substrate. The limited results reported by Varanasi et al [19] have been attributed to the high surface roughness.…”

“…A J c as high as 2 MA cm À2 was reported using this template [6]. In addition, constantan has been studied by several authors, as it is a commercially available alloy [15,[17][18][19]. Though it can be textured relatively well, there are no quantitative results on the superconducting properties of YBCO film grown on such a substrate.…”

Yield Strengths of Biaxially Textured Metallic Substrates (Ni and its Alloys) Determined Using a Simplified Test Method

“…The discussion on texture development and other properties of these substrates is reported elsewhere. 21 Briefly, as-received rod was rolled several times with a 10% reduction per pass to a final tape of thickness 50 lm. The rolled tape was cut into 3 mm wide tapes of different lengths (22, 28.5, 35 mm) and then annealed at 1200°C for 2 h in an Ar/H 2 atmosphere and then furnace cooled.…”