Phase transformation in Mg–8Gd–4Y–Nd–Zr alloy

Precipitation reactions in a Mg–8Gd–4Y–Nd–Zr alloy were investigated using hardness measurements, TEM and DSC, and a four stage precipitation sequence determined: Mg (SSSS) → β″ → β′ → β1 → β. Thermal effect signals in the DSC curves due to the formation of the β″, β′, β1 and β phases and the dissolution of the β″ phase were identified. The activation energies associated with the formation of the β′ and β1/β phases were determined according to the Kissinger method. These kinetic parameters were related to the heat-resistant mechanism of the Mg–8Gd–4Y–Nd–Zr alloy.

► We related the specific phase transformation processes to signals in the DSC curve.
► We determined the activation energies for the formation of the β′ and β1/β phases.
► High activation energy for β1/β formation leads to the attractive mechanical properties at elevated temperature.