Microstructure and mechanical properties of a rapidly solidified Mg94.5Zn2Y1.5LaMM1.5Mn0.5 alloy

Abstract

The microstructural evolution of rapidly solidified Mg94.5Zn2Y1.5LaMM1.5Mn0.5 ribbons during continuous heating up to 450 °C and after isothermal thermal treatments has been studied. Microstructural changes have been correlated with the mechanical properties of the material. Rapid solidification induces the formation of a metastable microstructure, which experiences different transformations during further heating. Such transformations involve precipitation of rounded Mg12RE particles, subsequent W-phase formation, and the final development of relatively thick plates corresponding to a phase with a long periodic stacking ordered structure (LPS-phase). The alloy in the rapidly solidified condition exhibits higher strength, in the 25-300 °C temperature range, than the material annealed at 400 °C for 1 h. © 2009 Elsevier B.V. All rights reserved.