S. Ochiai et al., MODELING ANALYSIS OF PRE-STRESS EFFECT ON UPPER CRITICAL MAGNETIC-FIELD AND CRITICAL-CURRENT OF NB3SN COMPOSITE WIRE, Science Reports of the Research Institutes, Tohoku University, Series A: Physics, Chemistry, and Metallurgy, 42(2), 1996, pp. 389-395
Citations number
22
Categorie Soggetti
Material Science","Metallurgy & Metallurigical Engineering
An analytical model to describe the variations of the upper critical m
agnetic field and critical current at 4.2K of the superconducting mult
ifilamentary Nb3Sn composite wire caused by the application of pre-str
ess at room tempearture was presented and applied to experimental resu
lts. Main results are summarized as follows. (1)The variations of the
upper critical magnetic field and critical current could be described
well as a function of pre-stress by combining the Ekin's scaling law w
ith the elastic/plastic mechanical calculation. (2)It was demonstrated
experimentally and theoretically that the upper magnetic filed and cr
itical current can be improved by the pre-stressing treatment through
the control of residual strain of Nb3Sn. (3)The strength distribution
of the Nb3Sn filaments was estimated for the first time by extracting
the influence of breakage of Nb3Sn filaments from the change in critic
al current of pre-stressed composite. (4)The procedure to predict the
relation between critical current at 4.2K and pre-stress at room tempe
rature for engineering-scale long samples was presented based on the p
resent model. An example of the application indicated that the permiss
ible overall pre-stress on composite, below which all Nb3Sn filaments
transport current without breakage, is reduced by approximate to 20 %
for long specimens of 300m in comparison with that for the short speci
mens of 25mm, while the average strength of Nb3Sn for 300 m is reduced
by approximate to 60 % from that for 25mm.