Nb-Ti superconductors of a high current-carrying capacity

Abstract

The effect of multiple prolonged heat treatment on the structure and critical current density in Nb50 wt% Ti composites was studied in the case of monofilamentary superconductors. The treatment temperature range, in which high ic vaiues can be obiained, is aeierminea. i i n e iniiuence o i intermeaiaie ireaimenis on the increase in the quantity of precipitated a-phase is studied. The exponent specifying the kinetics of particle growth from the supersaturated solid solution is estimated. The interrelation between the critical current density and the quantity of precipitated phase is established. The maximum critical current density is 4 x IO5 A cm-' (E = 5 T).

Analysis Method of High-Field Pinning Centers in NbTi Wires and MgB2 Wires

“…The formation rate of Ti precipitates between grains is dependent on the Ti content in the NbTi material [41], the density of crystal dislocations [4,42,43], size and number of the voids [40,44], the shapes of the NbTi grains, the heating temperature, and amount of the metastable phases [45]. After annealing, the Ti precipitates between grains have thickness of 100-200 nm [41][42][43][44][45][46][47][48]. Lee suggests that a large number of Ti precipitates between grains (about 10%) are produced during the first heating process [37].…”

“…The thickness of these precipitates is decreased by using cold working for NbTi wires. The cold drawing allows us to obtain Ti precipitates between grains with a thickness of 1-5 nm [41][42][43][46][47][48][49]. Additionally, the cold drawing increases the length of the Ti precipitates between grains from 50-100 nm to 1-10 μm [38].…”

Lasers—past, present, and future (Interviews with three Nobel laureates in 1982)

“…At low content of the precipitated phase ϕ in Nb-Ti superconductors the value of J c was experimentally found to grow linearly with the content of titanium particles (J c ∝ ϕ) [4,5]. According to a theoretical estimation made in a stratified model, both the pinning force of the magnetic flux and the critical current density J c have a maximum at ϕ ∼ 40 vol% Ti [6].…”

Studying the structure of the elements of the cable of technical superconductors by atomic force microscopy

“…Конструкция сверхпроводящего кабеля состоит из нескольких тысяч сверхпроводящих жил диаметром 2…5 мкм, фиксируемых медной матрицей [2]. К таким кабелям предъявляются высокие требования, наиболее важными из которых являются величина и стабильность критических параметров, стабильность токовых характеристик, безобрывность сверхпроводящих волокон (жил), их структурная однородность по длине провода и малые отклонения от геометрических размеров поперечного сечения [3][4][5].…”