Effects of Cu and Ce co-addition on the microstructure and mechanical properties of Mg-6Zn-0.5Zr alloy

In this work, the microalloying approach was adopted to improve the mechanical properties of Mg-6Zn-0.5Zr alloy by co-addition of trace Cu and Ce elements. The results showed that the grain size of the Mg-6Zn-0.5Zr-0.5Cu-0.5Ce alloy was refined, and MgZnCu and Mg-Zn-Ce phases formed by the microalloying of Cu and Ce. In addition, high-density nano-scale precipitates were found in the matrix after extrusion. The alloy with Cu and Ce addition showed a basal texture with a stronger texture intensity. The yield strength, ultimate tensile strength and elongation of the as-extruded Mg-6Zn-0.5Zr-0.5Cu-0.5Ce alloy were 304 MPa, 345 MPa and 20.0%, respectively. This work demonstrated a close microstructure-strength relationship in which the refined grain size and abundant nano-scale precipitates led to an increase in the tensile yield strength of approximately 59 MPa compared with that of the Cu and Ce free alloy. (C) 2018 Elsevier B.V. All rights reserved.