FUTURISTIC IN-SITU AND EX-SITU APPROACHES FOR SYNTHESIS OF SUPERIOR MAGNESIUM NANOCOMPOSITES

Abstract

Magnesium nanocomposites, with excellent specific strength, thermal and damping properties, are not industrially viable due to poor control of reinforcement dispersion in matrix and inability to tailor matrix-reinforcement interface which dictate their properties. This thesis describes a controlled approach combining the benefits of conventional processing with those of thermodynamic principles to synthesize magnesium nanocomposites. Mg-1.8Y alloy is chosen as matrix and an in-situ synthesis mechanism is established through addition of thermodynamically favorable nanoparticles (ZnO) and is contrasted with ex-situ synthesis (Y2O3 added Mg-1.8Y alloy). This technique is applied to synthesize in-situ Mg-1.8Y/1CaO nanocomposite with unparalleled properties (tensile strength ~343MPa, weak texture mediated tensile ductility ~30%, compressive failure strain ~44%, ignition temperature ~1045oC i.e. near the boiling point of Mg), outperforming other traditional Mg based materials. This approach, resultant of a vigilant choice of alloying element and reinforcement, is a solution to develop high performance magnesium nanocomposites, enabling nanocomposites industrially realizable.