Effect of Zn, Cu and Ni addition on microstructure and mechanical properties of as-cast Mg-Dy alloys

Abstract

This paper presents some research information on the effects of Zn, Cu and Ni on the microstructure and mechanical properties of as-cast Mg-2Dy (at.%) alloys. The Mg-2Dy alloy is composed of α-Mg and Mg24Dy5 phases. With the addition of 0.5at.%Zn, 0.5at.%Cu and 0.5at.%Ni, respectively, besides α-Mg, the long period stacking order (LPSO) phases containing Zn, Cu, and Ni precipitated in the α-Mg interdentritic boundary. The addition of Ni effectively refined the dendrite arm spacing. The as-cast Mg-2Dy-0.5Ni alloy exhibited the best tensile strengths and elongation. The better mechanical properties were mainly attributed to small secondry dendrite arm spacing (SDAS) and high volume fraction of LPSO phases.

Keywords

• Mg-Dy-Zn(Cu
• Ni) alloys
• LPSO phase
• microstructure
• mechanical properties