COMPARISON OF SITE OCCUPATION DETERMINATIONS BY APFIM AND AEM

A comparison of the site occupation of a substitutional element determined from atom probe field-ion microscopy and from zone axis electron channeling microanalysis in the analytical electron microscope is presented. These techniques permit the site occupation for multiple elements to be determined in polycrystalline specimens. The material used in these experiments was an L12 ordered (A3B) Ni - 24 at.% Al - 0.24 at.% B series of alloys containing additions of hafnium, cobalt, or iron. The results of these two techniques indicated that, for the particular alloy compositions studied, hafnium has a strong preference for the aluminum sites, cobalt has a strong preference for the nickel sites, and iron has a weak preference for the aluminum sites. These results are in agreement with the site preference suggested from the direction of the solubility lobes in experimentally determined ternary phase diagrams