Variations in microstructure and mechanical properties of ZK60 alloy sheets were investigated with aging time. ZK60 alloy sheets with a thickness of 1mm were prepared from a casting ingot followed by homogenization and warm-rolling. Artificial aging process after solution heat treatment (T6) affected both hardness variations and precipitates distributions with aging time. Hardness variations were related to precipitates, i.e. rod-shaped ( 1 β ′ ) or disc shaped ( 2 β ′ ) particles. Rod-shaped ( 1 β ′ ) precipitates mainly consist of Mg and Zn without Zr.