Investigation of the effect of WS₂/ZrB₂ hybrid nanoparticles on the mechanical properties of the AZ31 magnesium alloy

AZ31 Magnesium alloy has attracted attention in various industries due to its high strength-to-weight ratio. However, this alloy's low strength and ductility have limited its application. Reinforcing this alloy with nanoparticles can increase strength and maintain ductility. In this study, WS2/ZrB2 hybrid nanoparticles have been added to AZ31 Magnesium alloy. To prepare hybrid nanopowder, ZrB2 micropowder was subjected to a high-energy planetary ball mill for 8h to achieve a nanoscale powder. The resulting powder was mixed with WS2 nanoparticles by milling for 2h to produce a homogeneous hybrid nanoparticles powder. The hybrid nanoparticles were dispersed into the molten matrix using the stir casting technique, and nanocomposite specimens with different compositions were cast into the metallic molds. The microstructure of the nanocomposites was evaluated using optical microscopy (OM) and scanning electron microscopy (SEM). The results indicated that the reinforcing particles were well-distributed within the matrix and contributed to the grain refinement and morphological refinement of the Mg17Al12 intermetallic phase. Energy-dispersive spectroscopy (EDS) analysis and XRD test confirmed these findings. Hardness and tensile test were conducted on the fabricated samples. Due to the higher hardness of ZrB2 compared to WS2, the AZ31/1vol%ZrB2 nanocomposite exhibited the highest hardness value (HBN 58). The tensile test results demonstrated that the AZ31/0.5vol%WS2-0.5vol%ZrB2 nanocomposite achieved the highest tensile strength while maintaining excellent ductility and the thermal expansion coefficient mismatch was the dominant mechanism in the strength of nanocomposites.