The automobile industry uses magnesium for load-bearing components due to its low density, durability, and ductility. This study investigated a nanocomposite containing Nb2O5 (3 and 6 wt%) nanoparticles as reinforcement with AZ31 magnesium alloy made by stir casting. A severe plastic deformation was conducted on the cast samples via equal-channel angular pressing (ECAP) after homogenization at 410 °C for 24 h and aging at 200 °C for 10 h. The microstructural distributions and mechanical properties of the magnesium metal matrix composites (MMCs) reinforced with Nb2O5 nanoparticles were investigated via ECAP. With the increase in the number of ECAP passes, the grain sizes became uniform, and the size of secondary phases reduced in the pure Nb2O5/AZ31 MMC. The grain size decreased remarkably after the ECAP process from 31.95 µm to 18.41µm due to the dynamic recrystallization during plastic deformation. The mechanical properties of hardness, ultimate tensile strength, and elongation effectively improved after each ECAP pass. The maximum values achieved for the Nb2O5/AZ31 composite subjected to ECAP were 64.12 ± 12 HV, 151.2 MPa, and 52.71%.

There have been remarkable improvements in the research field of magnesium over the last few decades, especially in the magnesium metal matrix composite in which micro and nanoparticles are used as reinforcement. The dispersion phase of nanoparticles shows a better microstructural morphology than pure magnesium. The magnesium metal matrix nanocomposite shows improved strength with a balance of plasticity as compared to the traditional magnesium metal matrix composite. In this research, Nb2O5 (0 wt.%, 3 wt.%, and 6 wt.%) nanoparticles were used to reinforce AZ31 with the stir casting method, followed by heat treatment, and finally, an investigation was conducted using microstructural analysis. Factors such as the degree of crystallinity, crystallite size, and dislocation density are affected by the concentration of Nb2O5 and heat treatment. With the compositional increase in Nb2O5 weight percentage, the grain size decreases up to 3% Nb2O5 and then increases gradually. The SEM image analysis showed a grain size reduction of up to 3% Nb2O5 and fracture morphology changed from basal slip to a mixture of basal slip and adiabatic shear band.