Abstract

Magnesium is an attractive metal for various technological applications due to its low density (23% of steel and 66% of aluminum) and availability. Applications of magnesium in the automotive and aerospace industries aim for weight reduction and enhanced fuel efficiency.

However, magnesium has low toughness and low ductility, leading to a lack of formability, and these features limit its suitability for many applications. According to previous studies, enhanced mechanical properties can be achieved via alloying with certain solutes. In this study, three Mg binary alloys containing 1wt% Zn, 1wt% Al and 1wt% Y, were produced in the laboratory by casting using an induction furnace, and then processed by hot rolling at 250 °C using three passes, each of 50% reduction, to a final thickness of ～3 mm, to get sheets with a grain size of ~ 13 μm. Subsequently, some tensile tests were performed to failure at room temperature in order to characterize the full mechanical response as a function of the initial composition.

In addition, other set of samples were tensile tested up to a strain of ～10% in order to analyze the operative deformation mechanisms by electron backscatter diffraction (EBSD)-assisted slip trace analysis. Twinning mechanism was also evaluated by conventional electron backscatter diffraction. Therefore, the aim of this study is to assess the activity of the dominant deformation systems in three magnesium binary alloys. The incidence of the different systems is then related to the alloy composition, initial texture, misorientation distribution and mechanical properties. It is shown, that basal slip is the dominant deformation mechanism under tension in all the compositions investigated.

However, it is observed that Zn is the most effective alloying element to improve mechanical properties of Mg-based binary alloys in comparison to Al and Y. The Mg-Zn alloy presents the highest yield and maximum strength in comparison to the Mg-Al and Mg-Y alloys. The enhanced mechanical properties of the Mg-1wt%Zn alloy are rationalized based on the measured slip activities by EBSD-assisted slip trace analysis.