Tie line compositions of ternary Cu–Ag–Au alloys within miscibility gap

Tie line coordinates of ternary Cu–Ag–Au alloys in the solid immiscible region of the equilibrium phase diagram were determined experimentally by electron probe microanalysis. The two solid phases were analysed in samples which had been thermally treated from the as–cast condition to coarsen the phases. Tie line coordinates were also calculated theoretically using a thermodynamic model which is an extension of the regular solution model. The theoretical calculations agree well with the experimental analysis of the copper–rich phase as well as with a corrected analysis of the silver–rich phase. The necessity for the correction was attributed to the thermal coarsening treatment of the samples.

MST/191