  Bragg coherent diffraction imaging (BCDI), the well-established technique for
imaging internal strain of nanoparticles, was used to image the internal
compositional distribution of binary alloys in thermal equilibrium. The images
experimentally obtained for Pd-Rh alloy nanoparticles are presented and
discussed. The direct correspondence between the lattice strain and the
compositional deviation is discussed in the derivation of the BCDI displacement
field aided by illustrations.
