Moiré Fringes and/or Translation-Fault Fringes?

Interference fringes on transmission topographs of crystals with an implanted amorphous layer are, among others, attributed to the moiré or the translation-fault effect. This discussion is reconsidered in the frame of the theory of a perfect bicrystal extended to a deformed one. It is shown that translation-fault fringes have the same properties as moiré fringes and that it is not necessary to introduce translation-fault fringes as a new diffraction phenomenon.