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.

A method of metal forming known as severe plastic deformation (SPD) produces ultrafine-grained (UFG) structures and nanostructured materials with a high lattice defect density (Al-Qawabah and Zaid, 2016; Tajudin et al., 2023). Because of UFG’s high mechanical and physical properties, as well as its fatigue life improvement through the SPD technique, the structure is of great scientific interest. Metals and alloys can be strengthened with SPD techniques by causing large plastic deformations, producing true strains greater than one (Singh, Agrawal, et al., 2023). Equal channel angular pressing (ECAP) is one of the SPDs used to refine grain size. In 1972, equal-channel angular pressing was discovered. In metal alloys, ECAP processing has become a well-established procedure for grain refinement. A submicrometer grain particle is usually obtained by ECAP compared to a micrometer grain particle by thermo-mechanical treatment (Van Swygenhoven, 2002). At high strain rates, UFG particles exhibit superplastic ductility, giving them excellent material properties. By applying strain heat to aluminum and magnesium alloys, UFG particles are produced with superior mechanical properties (Mirzadeh, 2023). In most cases, SPD is performed at temperatures below 0.04Tm, where Tm refers to the melting temperature, at high pressures and relatively low temperatures. A particular advantage of equal-channel angular pressing over other SPD techniques is its ability to process relatively large bulk samples without requiring the dimensions to be altered, which makes it an attractive method for industrial applications. Science has always underestimated and neglected this process, but the fact remains that selecting appropriate parameters for different materials, such as channel angle, plunger speed, and operating temperature, results in desired properties (Alateyah et al., 2023; Krajnˇák et al., 2017). Based on the schematic shown in Figure 5.1, the plunger provides motion to the sample, the heating coils regulate die temperature, and the angle varies from die to die depending on the deformation required. <!----> <!----> <!----> <!---->