We reconstruct three-dimensional images of phase ordering in an Fe-Al alloy by coherent X-ray diffraction imaging based on Bragg ptychography. The B2 phase in Fe-Al alloys shows an atomic structure that is ordered on a bcc sub-lattice. This results in the emergence of (001) superlattice Bragg reflections that are sensitive to atomic ordering information as well as to general lattice distortions. The fundamental (002) Bragg reflection is only sensitive to lattice distortions and hence by reconstructing the phase maps of both reflections the atomic ordering can be deduced.