Characterization of Al-Si Alloy Reinforced with B₄C and TiO₂ Nanoparticles

Al-Si alloy as a matrix in Aluminium Metal Matrix Composites (AMCs) augments the hardness and strength. The work reports the characterization and mechanical properties of Hybrid Aluminium Metal Matrix Nanocomposites (HAMNCs) using Hypereutectic Al-Si grade LM30 alloy as the matrix with boron Carbide (nB₄C) and Rutile (nTiO₂) nanoparticles as reinforcements. Liquid metallurgy route ultrasonic squeeze-assisted stir-casting was employed to manufacture hybrid formulations. The HAMNC specimens were fabricated by maintaining 1 wt.% of nB₄C and by varying TiO₂ nanoparticles in steps of 0.25 wt.% in the 0 to 1 wt.% range. The optical micrographs revealed that ultrasonic vibration and squeeze casting effects aided the uniform distribution of nano reinforcements and lowered the porosity. XRD analysis revealed the formation of Aluminum Titanium Silicate (Al₄Ti₂SiO₁₂) due to the addition of nTiO₂. The results highlighted that the LM30 matrix having 1.0 wt.% of nB₄C and 0.75 wt.% of nTiO₂ exhibited the maximum hardness of 107.2 HRB, ultimate tensile strength of 265.52 MPa, and compressive strength of 656 MPa. The tensile fractography using FESEM highlighted the various kinds of dendrites associated with the fracture. nB₄C and TiO₂ nano reinforcements increased energy absorption during impact failure.