Microsc. Microanal. Microstruct. 3, 387-400 (1992)
DOI: 10.1051/mmm:0199200305038700

The miscibility gap in the FeBe system

Michael K. Miller¹ et Mary Grace Burke<sup>2

1</sup>  Metals and Ceramics Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831-6376, U.S.A.
²  Westinghouse Science and Technology Center, Pittsburgh, PA 15235, U.S.A.

Abstract
The technique of atom probe field ion microscopy has been used to estimate the position of the low temperature miscibility gap in the iron-rich portion of the iron-beryllium system by direct measurement of the compositions of the phases. The morphology of the two phases produced by spinodal decomposition within this miscibility gap was determined to be a dislocated macrolattice of isolated cuboidal particles of the iron-rich α phase embedded in a matrix of the B2-ordered beryllium-enriched FeBe phase. Atom probe measurements indicated that there was a significant variation in the compositions of the coexisting phases and the differences in the beryllium contents between the phases increased with aging time at 350 and 400 °C.

PACS
8130B - Phase diagrams of metals and alloys.
6837V - Field emission and field-ion microscopy.

Key words
Phase diagrams -- Miscibility gap -- Chemical composition -- Atom probe field ion microscopy -- Spinodal decomposition -- Binary alloys -- Iron base alloys -- Beryllium alloys -- BeFe alloys


© EDP Sciences 1992