Phase changes and structural features of Cu₃Au II in a gold–copper–silver ternary alloy during isothermal ageing

The isothermal phase changes and associated structural features of a long period superstructure of Cu₃Au II in a Au‐55.2 at% Cu‐17.4 ag% Ag alloy are studied by means of X‐ray powder diffraction and electron microscopy. A characteristic long period antiphase boundary structure of the Cu₃Au II is only induced within a grain boundary product during isothermal ageing at 633 K. The phase changes occurred in the present alloy are interpreted rationally on a superimposed plausible incoherent phase diagram on the coherent phase diagram of the goldCopperSilver ternary system.