Microstructure development in Nb3Sn(Ti) internal tin superconducting wire

Abstract

The authors have studied the phase formation sequences in a Nb 3 Sn 'internal tin' process superconductor. Heat treatments were performed to convert the starting materials of tin, Ti-Sn, copper and niobium, to bronze and Nb 3 Sn. Specimens were quenched at different points of the heat treatment, followed by metallography to identify the phases present and X-ray microtomography (XMT) to investigate the void volume and distribution. An unexpected observation of the microstructure development was the uphill diffusion of tin during the Cu-Sn reactive diffusion. Some defects likely to affect the superconducting performance of the wires were observed. Microscopy revealed the presence of a Ti-Sn intermetallic compound displacing the niobium filaments, and XMT revealed the formation of long pores in the longitudinal direction. Two types of pore formation mechanism, in addition to Kirkendall pores, are proposed. The phase and microstructure development suggests that low-temperature heat treatment (below 415°C) will have significant influence on optimising the final superconducting properties.

Ab initio investigation of spin orbit coupling effect on the physical properties of IrGe superconductor

“…The reason for this is that the processing of high-temperature oxide compounds in the form of flexible compounds such as wires or coils is still very difficult to achieve due to their brittle, salt-like structure. Thus, intermetallic compounds are usually used as superconducting magnets and wires [2][3][4]. Recently, this special interest has gravitated towards intermetallic superconductors based on heavy 5d transition metals such as Ir and Pt which are chracterised by large spin orbit coupling (SOC).…”

Структура И Свойства Материалов На Основе Сплавов И Тонких Пленок Ниобия С Оловом

“…Затем сплавы и интерметаллические соединения [2,3], их физические [4,5] и химические свойства исследовали многие авторы [6,7]. Интерес к сплавам ниобия с оловом связан со сверхпроводящими свойствами интерметаллических соединений, особенно металлида Nb 3 Sn [8][9][10][11].…”

Properties of the Superconducting State in Hexagonal BaSn5

“…Thus, intermetallic superconductors are commonly used for technological applications. In superconducting magnets and wires most popular are Nb 3 Sn and Nb 3 Ge compounds with A15 structure [3]. A few years ago it has been shown that BaSn 5 has similar electronic properties to the A15 superconductors [4].…”