Title :
Influence of Al Composition Thickness on Critical Current Density in Transformation-Processed
Superconductors
Author :
Banno, N. ; Tsuchiya, K. ; Nakamoto, Takamichi ; Kikuchi, A. ; Takeuchi, T. ; Iijima, Y. ; Tomita, K. ; Kato, Shigeo ; Suzuki, Kenji ; Takao, Tomoaki ; Nakagawa, Koichi
Author_Institution :
Nat. Inst. for Mater. Sci., Tsukuba, Japan
Abstract :
The influence of the Al layer thickness on the critical current density Jc of transformation-processed Nb3Al superconductors was investigated. The Al layer thickness in the jerry-roll filaments of precursor wires was varied from 120 to 250 nm; the Nb layer thickness is proportional to the Al thickness, keeping the Nb-Al composition ratio to 3. The rapid heating and quenching (RHQ) operation condition was varied within a range of the conditions to form the ductile body-centered cubic (BCC) Nb-Al phase. The RHQ wires were also followed by an areal reduction process prior to the Nb3Al phase transformation. Thinner Al thickness wires show a steeper increase in Jc with reduction in the area, whereas thicker Al thickness wires show a slower increase. The best Jc performance was obtained for the thinnest Al thickness sample. Without areal reduction, there was not much difference in the optimum Jc with respect to the Al thickness.
Keywords :
aluminium alloys; critical current density (superconductivity); niobium alloys; quenching (thermal); Nb3Al; RHQ operation condition; areal reduction process; composition thickness; critical current density; jerry-roll filaments; precursor wires; rapid heating and quenching operation condition; transformation processed superconductors; Conductors; Critical current density (superconductivity); Microstructure; Niobium; Superconducting magnets; Wires; $J_{rm c}$ characteristics; $hbox{Nb}_{3}hbox{Al}$; Al layer thickness; phase transformation; rapid-heating and quenching (RHQ);
Journal_Title :
Applied Superconductivity, IEEE Transactions on
DOI :
10.1109/TASC.2014.2359547