Analytical electron diffraction technique for the determination of long-range order parameters in multi-component ordered alloys

A combination of the channelling enhanced X-ray microanalysis (ALCHEMI) and the intersecting Kikuchi-line (IKL) method in transmission electron microscopy is used as a technique to determine long-range order (LRO) parameters of multi-component alloys. This technique, IKL-ALCHEMI, opens up a field of research on atomic configuration in multinary alloys with imperfect order, taking advantage of a transmission electron microscope equipped with an EDX spectrometer. An application of IKL-ALCHEMI to L1₀-type ordering in CuAuPd ternary alloys has successfully quantified occupation probabilities of the three elements on the two sublattices as a function of alloy composition. The result clearly shows the effective ordering interactions between first nearest neighboring pairs V_ij to be V_CuPd> V_CuAu ≫ V_AuPd.