Abstract:Phase separation processes of cast ZA₂₇ alloy aged at room temperature and 100 ℃, respectively were studied by means of transmission electron microscope, X-ray diffraction and microhardness measurment. It was concluded that G P zones form at early stage of ageing phase separation when ZA₂₇ alloy is aged at room temperature, but the alloy undergoes spinodal decomposition process, in which concentration waves develop along 〈111〉, a soft direction in elastic, when aged at 100 ℃.

Key words: Zn Al alloy spinodal decomposition G P zone phase transformation