Formation of quasicrystals and approximant crystals by mechanical alloying in MgAlZn alloy system

Abstract The mechanical alloying technique has been applied to study the formation range of quasicrystals and related approximant crystals in the MgAlZn system. Three different mills were employed. An increase in both acceleration intensity and ambient temperature during milling turns out to be effective in increasing the formation rate of the quasicrystalline phase. The formation range of quasicrystals is apparently divided into two groups: one along the composition line Mg 32 (Al, Zn) 49 and the other centered around Mg 10 Al 3 Zn 7 . By heating in the DSC run, quasicrystals in the former exhibit the exothermic peak upon crystallizing into the Frank-Kasper phase at 200–300°C. On the other hand, those in the latter substantially improve quasicrystallinity and then exhibit the endothermic peak upon crystallizing into the (2/1–2/1–2/1) approximant phase above 400°C.