Phase stability at high temperatures in the Nb-Al system

Author

Buta, Florin ; Sumption, Michael D. ; Collings, Edward W.

Author_Institution

Dept. of Mater. Sci., Eng. of The Ohio State Univ., Columbus, OH, USA

Volume

13

Issue

2

fYear

2003

fDate

6/1/2003 12:00:00 AM

Firstpage

3462

Lastpage

3465

Abstract

The phases present in the Niobium-Aluminum system were investigated by X-ray diffraction and scanning electron microscopy on jelly-roll composites of 23.5, 27.5 and 35.0 at% Al, quenched after being heated in various time intervals (0.3 sec-5 min) to temperatures in the vicinity of the bcc formation temperature. In the present configuration, at concentrations around 27.5 at% Al the bcc phase is the product of an eutectoidal reaction between A15-structure Nb₃Al and sigma-phase Nb₂Al. This eutectoid has not been found in any of the published equilibrium phase diagrams, a revised equilibrium phase diagram is proposed.

Keywords

X-ray diffraction; aluminium alloys; composite superconductors; niobium alloys; phase diagrams; quenching (thermal); scanning electron microscopy; A15 structure; BCC phase; Nb-Al; Nb-Al system; Nb₂Al; Nb₃Al; X-ray diffraction; equilibrium phase diagram; eutectoidal reaction; high temperature phase stability; jelly-roll composite; quenching process; scanning electron microscopy; sigma phase; superconducting material; Heat treatment; Heating; High temperature superconductors; Niobium; Solids; Stability; Superconducting cables; Superconducting coils; Temperature distribution; Wire;

fLanguage

English

Journal_Title

Applied Superconductivity, IEEE Transactions on

Publisher

ieee

ISSN

1051-8223

Type

jour

DOI

10.1109/TASC.2003.812358

Filename

1212373