Side bands of fundamental reflexions of Cu-20 at.% Au and Cu-21 at.% Au alloys

With the use of Debye-Scherrer X-ray back-reflection photographs, the simultaneous existence of side bands of fundamental reflections and diffuse superstructure lines has been detected in samples of Cu-20 at. % Au and Cu-21 at. % Au, quenched from above the critical temperature of ordering T_c and subsequently heated to just below T_c. The intensity of side bands and superstructure lines increases with quenching temperature. The modulated structure of ordered domains in the disordered matrix gives an explanation of the observations.