Effect of Zinc on Solidification and Aging Behaviour of Magnesium Alloys Containing Rare Earths

Abstract

Magnesium sheet continuously creates a great interest with potentials in a wide range of technically advanced applications. The interest was initially driven by a reduction in fuel consumption within transportation sectors and was later expanded to consumer electronic housings, components in electrification of vehicles, and aerospace applications. In a search for alloys with suitable formability , a particular attention is paid to Mg–Zn –RE (rare earth ) grades. It is known that the presence of Zn in binary Mg–Zn alloys leads to enhanced strength and ductility. However, the effect of Zn on alloy formability in the presence of rare earths is less pronounced. In this report, the solidification and aging behavior of Mg–xZn–1Nd (x = 1, 2, 4 wt%) alloys are described. To analyze the phase nucleation and growth during melting and solidification, the Universal Metallurgical Simulator and Analyzer (UMSA) was used. Hardness values of Mg–Zn –Nd alloys increased with increasing Zn contents both in as-cast and after heat treatments with changes being accompanied by the alloy structure refinement. The results are discussed in terms of the role Zn plays in properties of magnesium alloys containing rare earths. Increasing Zn content in the Mg-xZn-1Nd alloy sheets led to a moderate increase in ultimate tensile strength and yield stress but substantial reduction in ductility.