Optimization of mechanical properties of dilute Mg-Zn-Y alloys prepared by rapid solidification

Abstract

The presented work is focused on the investigation of dilute Mg-Zn-Y alloys prepared by the consolidation of rapidly solidified ribbons. Particularly, the influence of both amount of the Zn and Y alloying elements (varies between 1 and 2 at.%) and the metal flow rate during extrusion on the initial microstructure and resulting mechanical properties is discussed. The average grain size of investigated alloys varies between 700 and 1200 nm. Furthermore, dispersive Zn- and Y-rich stacking faults are observed in dynamic recrystallized grains. The optimal tensile properties (yield strength and elongation of 362 MPa and 18.2%, respectively) are achieved for the Mg97.94Zn0.56Y1.5 alloy extruded at 1.9 s−1. The detailed microstructural analysis indicates inhomogeneous internal strain distribution in the bimodal microstructure, which is found of key importance for mechanical performance. Keywords: Magnesium alloys, Microstructure, Mechanical properties, KAM, Rapid solidification