Study on the synergetic effect of Gd and Y alloying on the microstructure and deformation behavior in magnesium.

Magnesium (Mg) alloys, owing to their lightweight, have gained substantial attention in industries such as aviation and automotive. Researchers are continuously working on different strategies to improve the performance of Mg alloys, among which alloying is of prime importance. However, care has to be taken so as to avoid over alloying of Mg as that would degrade the lightweight advantage of Mg. Addition of gadolinium (Gd) and yttrium (Y) to magnesium holds promise for improving mechanical performance, but a detailed comprehension of their synergetic effect on alloy's microstructure and deformation behaviour is crucial, which forms the basis of this study. Mg alloys with varying percentage of Gd and Y are developed in this study using gravity casting method. Microstructural assessment revealed a complex interplay of phases, including the presence of eutectic structures among other strengthening precipitates. Distribution and morphology of these microconstituents are studied in detail through electron microscopic techniques. Mechanical performance of the materials is assessed through tensile testing. Results indicated that the incorporation of Gd and Y influenced critical resolved shear stress (CRSS) values, affecting the activation of specific slip systems and twin systems. Post-deformation analysis preformed through fractography provided valuable information on the fracture modes and failure mechanisms, contributing to a comprehensive understanding of the alloy's reliability. Mechanisms leading to a typical microstructure and a resultant mechanical performance for Mg-Gd-Y alloy is discussed in detail.