Influence of Preparation Process on Microstructure, Critical Current Density and Tc of MgB2/Fe/Cu Wires
نویسندگان
چکیده
The powder-in-tube MgB2 wires were prepared by high energy milling of Mg and B powder. The powder was not mechanically alloyed for 2h short milling time. However, the MgB2 grains in wires are very small (20 100nm) and resembled to the dimple after post-heat treatment. The clear evidence for transcrystlline fracture is observed. It indicated that the grain connection was greatly improved and the fluxing pinning was significantly enhanced. Another point to view is no intermediate annealing was adopted during the whole rolling process. The influence of the post-heat treatment on the transport current density was studied. Despite the lower Tc of about 35K, the transport current density reaches to 3× 10A/cm at 15K and 3.5T for 700 ◦c sintered wires. PACS numbers: 74.70.Ad, 74.62.Bf, 74.25.Qt, 74.25.Sv, 74.50.+r, 74.70.-b † To whom correspondence should be addressed ([email protected]) Influence of Preparation Process on Microstructure, Critical Current Density and T c of MgB2/Fe/CuWires2
منابع مشابه
پیشرفتهای اخیر در زمینه ساخت سیم و نوار ابررسانای MgB2
MgB2 wire and tape were prepared using the powder in tube and reaction in-situ technique. All samples were characterized using the XRD, SEM, TEM, as well as transport and magnetic measurements. High transport and magnetic critical current density values have been obtained for metal-clad wires and tapes. Different sheath materials have been examined, but Fe appears to be the best sheath for MgB...
متن کاملEffect of ball milling on the local magnetic flux distribution and microstructure of in situ Fe/MgB2 conductors
The effects of the precursor milling energy on the superconducting and microstructural homogeneity of Fe-sheathed MgB2 monocore wires and tapes have been investigated. The conductors were produced by the powder-in-tube method using drawing and rolling deformation methods and in situ reaction. Combined magnetooptical, structural and magnetization measurements were performed on MgB2 superconducti...
متن کاملTransport and magnetic critical current in superconducting MgB2 wires
Direct comparison of the magnetic and transport critical current density (Jc) for the same pieces of copper-sheathed MgB2 wires shows a large discrepancy in magnitude and field dependence of the two. The value of magnetic Jc can differ from the value of transport Jc by a factor of 10 or more. This discrepancy does not occur merely because of the difference in the voltage at which the magnetic a...
متن کاملSintering Process and Its Mechanism of MgB2 Superconductors
The superconductivity at 39 K discovered in MgB2 among simple binary chemical composition attracted much interest in its fabrication techniques and practical applications [1]. MgB2 superconductor exhibits many impressive properties such as highest critical temperature amongst intermetallic superconductors which means low cooling costs, impressive grain boundary transparency to the flow of curre...
متن کاملImprovement in the transport critical current density and microstructure of isotopic Mg11B2 monofilament wires by optimizing the sintering temperature
Superconducting wires are widely used in fabricating magnetic coils in fusion reactors. In consideration of the stability of 11B against neutron irradiation and lower induced radio-activation properties, MgB2 superconductor with 11B serving as boron source is an alternative candidate to be used in fusion reactor with severe irradiation environment. In present work, a batch of monofilament isoto...
متن کامل