Alchemi of Fe-doped B2-ordered NiAl alloys with different doping levels

Recently, a formulation of the ALCHEMI technique has been presented that yields exact expressions for bestfit parameters in terms of the ionization localization constants and site distributions of three elements distributed over two sublattices. The application of this formulation to a NiAl-based B2-ordered alloy doped with 10% Fe used a graphical plotting technique to show that the size of the standard error of the best-fit parameters (and therefore of the site distributions) correlates with the extent to which the plotted data define a unique plane. The definition of the plane depends both upon the scatter of the data (Poisson statistics) and the spread of data over the best-fit plane (the variety of channeling conditions sampled). In this paper, the graphical plotting technique is applied to Fe-doped NiAl B2-ordered alloys of composition Ni0.5-xFexAl0.5 with x ∊ {0.02, 0.10}.Thin foil specimens of each composition were examined in a Philips CM 12 operated at 120 kV and equipped with an EDAX 9900 ultra-thin window energy-dispersive X-ray spectrometer.