Nb sub 3 Al Formation in Sputter-Deposited Nb/Al Multi-Layer Samples

摘要

The critical current density of powder metallurgy processed wires is determined in part by the extent of the A15 phase formation in the vicinity of the Nb/Al interface. A series of multi-layered samples was made to simulate the reactions in the P/M wires. Transmission electron microscopy was used to study the reactions between the multi-layers. Results indicate that the reactions at the Nb/Al interface depend strongly on the Nb and Al layer thickness and distribution. No evidence of the metastable NbAl solid solution formation was found. It is concluded that the Nb sub 2 Al and the residual Nb present in the reacted P/M wires can be avoided if the Nb and Al layers are sufficiently thin and uniformly distributed with the proper stoichiometry. 10 refs., 7 figs., 2 tabs. (ERA citation 13:009120)