Ion irradiation induced precipitation of γ phase in Cu-Zn-Al-Ni

The influence of ion irradiation on the formation of γ phase precipitates and the degree of long-range order was studied in β-Cu-Zn-Al-Ni alloys. Single crystals of β-Cu-Zn-Al-Ni and β-Cu-Zn-Al with surfaces close to (11¯0)β were irradiated simultaneously at normal incidence with 300 keV Cu ions at room temperature. The microstructural changes of both alloys, investigated with transmission electron microscopy (TEM), were compared. The formation of the γ phase in quaternary Cu-Zn-Al-Ni, induced by room temperature irradiation, was observed for the first time. Irradiation was not able to completely destroy first neighbor and second neighbor ordering in the quaternary alloy. The observed behavior under irradiation was compared to that of thermal treatments. The presence of γ phase precipitates in ion irradiated Cu-Zn-Al-Ni alloy is discussed.