On Precipitation Phenomena in Magnesium-Zinc Alloys

Abstract

The ageing characteristics of magnesium-zinc alloys in the composition range from 3.2 to 19.0 wt.% zinc were studied at temperatures from 70° to 200°C mainly with X-ray diffraction methods and electron-microscopic observations with thin foils. The G.P. zones were confirmed to exist on the {1011} matrix planes. The transition phase on the {1010} matrix planes is MgZn´ indistinguishable from the hexagonal Laves phase MgZn₂. The effects of plastic deformation were examined with direct observations by thin foils. The formation of G.P. zones on the {1011} matrix plane was hindered by cold working after water quenching, while the rates of precipitation of the transition phase β´ and equilibrium phase β were accelerated.