Publication

Abstract : The utilisation of recycled Mg–Al–Zn alloys in structural applications is limited by their insufficient corrosion resistance, poor wear properties, and reduced mechanical strength. To address these challenges, graphene (2–6 wt%) and BN (2 wt%) were reinforced into the recycled alloy using vacuum-assisted bottom-pouring stir casting. Microstructural observations revealed that graphene and BN promote finer dendrites and inhibit dendritic coarsening, appearing as tree-like facets that are finer, shorter, and more dispersed throughout the magnesium matrix. The extracted composites exhibited a decrease in density (0.54 ± 0.001%) while achieving enhanced hardness (45.88 ± 0.01%). Mechanical testing revealed a notable improvement in tensile (32.93 ± 0.01 %), compressive (39.58 ± 0.1 %), flexural (30.88 ± 0.01 %), and impact strength (34.48 ± 0.02 %), which can be attributed to enhanced load transfer, reduced dislocation movement, and a more refined microstructure. Furthermore, improved corrosion and wear resistance were observed due to the formation of stable intermetallic phases, including MgO, Mg2C3, and MgAl2O4, combined with the even distribution of ceramic reinforcements that create protective layers against degradation.