Orientation relationship and interfacial structure between α-Nb₅Si₃ and Nb solid solution in the eutectic lamellar structure

Abstract

The orientation relationship (OR) and the interfacial structure of the eutectic α-Nb₅Si₃ and Nb solid solution (Nbss) lamellar microstructure were investigated by transmission electron microscopy (TEM). The OR between α-Nb₅Si₃ and Nbss was determined as and . In spite of the significant difference in crystal structure between α-Nb₅Si₃ and Nbss, the interface was found to be semi-coherent with good matching. High-resolution TEM images of the α-Nb₅Si₃/Nbss interface are presented to describe the chemistry of the terminating plane of α-Nb₅Si₃. The results revealed that a pure Nb layer not Si or mixed (Nb + Si) layer of the α-Nb₅Si₃ phase was bonded to the Nb phase at the interface. A periodic array of edge-type misfit dislocations, with line direction and Burgers vector , was observed at the interface.

Keywords:

• microstructure
• orientation relationship
• interfacial structure
• α-Nb5Si3
• transmission electron microscopy

Acknowledgements

This work was supported by the National Natural Science Foundation of China and Special Funds for the Major State Basic Research Projects of China Grant No. 2006CB600905.