Phase transformations of eutectoid Zn-Al alloys

Systematic investigations on microstructures and phase transformations were carried out on solution treated, chilled as-cast and extruded Zn-Al based alloys (containing small amounts of Cu or Cu and Si). Phase transformation sequences of the thermal and thermomechanically treated eutectoid Zn-Al alloys were studied along with isothermal holding. Two new unstable phases ηS′ and ηE′ and their decomposition products in the chilled as-cast and extruded eutectoid Zn-Al alloys are discussed.