The microstructure of Nb3Sn superconductors differing in the number of copper inserts at various stages of heat treatment

27th International Cryogenics Engineering Conference and International Cryogenic Materials Conference 2018

Krylova, M.V.^1 ; Abdyukhanov, I.M.^1 ; Tsapleva, A.S.^1 ; Dergunova, E.A.^1^6 ; Mareev, K.^1 ; Alekseev, M.V.^1 ; Karateev, I.A.^2 ; Ovcharov, A.V.^2 ; Trunkin, I.N.^2 ; Potapenko, M.M.^1 ; Figurovsky, D.K.^3 ; Vasiliev, A.L.^2 ; Pantsyrnyi, V.I.^1 ; Zernov, S.M.^4 ; Gusev, E.N.^5

SC VNIINM Named by A.A. Bochvar, Russia^1

RRC Kurchatov Institute, Russia^2

RTU MIREA, Russia^3

SC TVEL, Russia^4

Chepetsky Mecanical Plant, Russia^5

National Research Nuclear University (MEPhI, Russia^6

关键词: Different stages;    High critical current densities;    Hysteresis loss;    Intermediate phasis;    Magnetic system;    Model samples;    Nb3Sn superconductor;    Scanning and transmission electron microscopy;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/502/1/012174/pdf
DOI  :  10.1088/1757-899X/502/1/012174

来源: IOP

【 摘 要 】

Superconducting materials with a high critical current density in magnetic fields up to 16 T at a temperature of 4.2 K are required to create magnetic systems of high-energy physics devices. We have studied the change of the microstructure of model samples of various designs with an internal tin source, differing in the number of copper separators (three, six and without them) at different stages of heat treatment. The formation of the following intermediate phases was studied: Cu3Sn, Cu6Sn5 and triple Cu-Sn-Nb phase after annealing at 370° C/100 h, by the use of scanning and transmission electron microscopy. The formation of the Nb6Sn5 phase on Nb filaments located close to the tin source and copper separators was studied after heat treatment at a temperature of 665° C from 10 minutes to 25 hours. The results of the analysis led us to understand the kinetics of the Nb3Sn and Nb6Sn5 formation in internal tin superconductors with an increased current-carrying capacity and a low level of hysteresis losses.