Powder Metallurgy Fabricated In-situ Al-Al2O3 Composite(HITEMAL)as a Sheath Material of MgB2 Based Superconductive Wire
This paper reviews development of special high strength in-situ Al-Al2O3 composites,named HITEMAL,fabricated by powder extrusion of fine atomized Al powders,which have appropriate properties for use in cryogenic conditions.It is confirmed that ultrafine-grained and thermally stabile HITEMAL sheath can be successfully used for fabrication of lightweight superconductive wire based on MgB2 core.The results proved that severely deformed HITEMAL wires provides advantageous mechanical and electrical properties,and surface integrity even after annealing up to high temperature of 650℃ held for 0.5 h.Mechanically HITEMAL sheath well stabilizes single Mg+B core of superconductive wire during cold working process and during wire`s service at cryogenic conditions.This study particularly elaborates an exceptional structural stability of severely deformed UFG Al structure close to its melting point,effectively stabilized by nanoscale Al2O3 particles,which stem from native amorphous Al2O3 layers on atomized Al feedstock powder.Effective stabilization prevents UFG Al structure from massive Al grain growth during exposures close to the melting point of Al and hence high strength of HITEMAL is maintained and utilized during service of superconductive wire.Critical temperatures and critical current densities of MgB2/HITEMAL with Ta or Ti barriers are comparable with the values of other superconductors with MgB2 core fabricated by internal Mg diffusion process and using Cu based sheath materials.
Al MgB2 in-situ composite powder superconductor high temperature stability ultrafine-grained
Balog Martin Kovac Pavol Krizik Peter Rosova Alica Orovcik Lubomir Kulich Milo Husek Imrich Kopera Lubomir Svec Peter
Institute of Materials and Machine Mechanics,Slovak Academy of Sciences,Dubravska cesta 9,84513 Brat Institute of Electrical Engineering,Slovak Academy of Sciences,Dubravska cesta 9,84104 Bratislava,Sl Institute of Physics,Slovak Academy of Sciences,Dubravska cesta 9,84511 Bratislava,Slovakia
国际会议
北京
英文
974-982
2018-09-16（万方平台首次上网日期，不代表论文的发表时间）