STP430: Electron Microscopy Applied to a Unidirectionally Solidified Al-Al3Ni Eutectic Alloy

    Tice, W. K.
    Research engineer, research supervisor, and research engineerpersonal member ASTM, United Aircraft Research Laboratories, East Hartford, Conn

    Lasko, W. R.
    Research engineer, research supervisor, and research engineerpersonal member ASTM, United Aircraft Research Laboratories, East Hartford, Conn

    Lemkey, F. D.
    Research engineer, research supervisor, and research engineerpersonal member ASTM, United Aircraft Research Laboratories, East Hartford, Conn

    Pages: 11    Published: Jan 1968


    Abstract

    Optical methods, replicas, and thin foils prepared by both ultramicrotomy and electropolishing techniques, as well as direct surface analysis by emission microscopy, were evaluated in order to characterize the interfacial crystallography and morphology of unidirectionally solidified Al-Al3Ni eutectic specimens. Replicas gave somewhat limited data due to the presence of subtle artifacts created during metallographic preparation, while emission microscopy gave considerably more topographical definition than that obtained by optical methods. Microtomed sections also proved to be of little value due to the plastic deformation induced by cutting. On the other hand, thin foils prepared by electropolishing methods clearly resolved the morphology of the dispersed Al3Ni phase and permitted direct determination of the interfacial plane, as well as the cristallographic orientation relationships between Al-Al3Ni. The A3Ni rods were found to be bounded by prismatic facets which were coincident with low index planes of aluminum lying in the ⟨110⟩ zone axis.

    Keywords:

    metallography, electron microscopes, aluminum-nickel alloys, eutectics, crystallography, microstructure, microtomy, dislocations


    Paper ID: STP41823S

    Committee/Subcommittee: E04.03

    DOI: 10.1520/STP41823S


    CrossRef ASTM International is a member of CrossRef.