PRECIPITATION BEHAVIOR IN CU-AG ALLOYS

Precipitation behaviour of the Cu-Ag alloys in the region of the maxim al solubility of silver was investigated by optical microscopy, EPMA, TEM and electron diffraction. Especially the formation of microstructu re in the initial stage of precipitation and the character of continuo us precipitation, as well as two kinds of discontinuous precipitation species were described. The first of three typical decomposition stage s of continuous precipitation has been identified as metastable silver -rich decomposition zones. The precipitation processes exhibit strong dependence on silver content: At higher silver contents the decomposit ion reaction is enhanced. For the discontinuous precipitation a critic al supersaturation of solid solution is needed.