Abstract: A strengthened Mg based alloy comprising Mg as a base element and at least two microalloying elements. A microstructure having at least one of dislocations, stacking faults, coherency strains, grain boundaries and dislocation domains decorated by segregation of microalloying elements. One of the microalloying elements is a large atom element having an atomic size larger than the atomic size of a Mg atom and another of the microalloying elements is a small atom element having an atomic size smaller than the atomic size of the Mg atom. The microstructure includes an absence of continuous films of grain boundary intermetallic compounds.