Precipitation microstructure and age-hardening response of an Mg–Gd–Nd–Zn–Zr alloy

Precipitates in an Mg–3.6Gd–2.8Nd–0.6Zn–0.4Zr (wt.%) alloy aged for times up to 70 h at 200 °C have been characterised using transmission electron microscopy and atom probe tomography. The precipitate phases known as β″, β′ and β1 occur during this ageing. The solute elements Nd, Zn and Gd partition significantly into these precipitates. The enhanced ageing hardening response after aged 70 h is mainly attributed to the precipitation of β′ and β1 with a number density by a factor of 10 less than that of β″ and β′ precipitates formed after 3 h ageing.