Nano-Al2O3 Particle Incorporated in Al Matrix Composite by Vortex-Free High-Speed Stir Casting

Abstract

Vortex-free high-speed stir casting (VFHSC) methodology can achieve uniform dispersion of particles in melt without air entrapment for fabricating particle reinforced composites, and it has been proved to be feasible for preparing micron-composites by this methodology. In this work, in order to study deeply on particles in nano-size magnitude in composites by this methodology, the preparation of 1.5 vol.% Nano-Al₂O_3p/Al–Cu–Mg–Si composite is also investigated. The proper stirring parameters for ideal particle dispersion are determined to prepare the materials. Porosity of the composite can be limited to 0.147 % under the VFHSC methodology. The composition and microstructure of ingots, including the incorporation of Al₂O₃ particles as well as the morphology of precipitated phases, are examined by OM, XRD, SEM, TEM, HRTEM and EDS. The nano-particles are incorporated ideally in the matrix with restricted aggregation and sedimentation, and the well-bounded Al₂O₃–Al interface possesses semi-coherent interface. Moreover, the VFHSC 1.5 vol.% Nano-Al₂O_3p/Al–Cu–Mg–Si composite exhibits obvious strengthening, limited ductility reduction, higher hardness as well as better wear resistance than those of matrix, validating the efficacy of the VFHSC methodology on fabricating 1.5 vol.% Nano-Al₂O_3p/Al–Cu–Mg–Si composite. The work proves that incorporating nano-particles in Al matrix by VFHSC methodology is feasible and efficient. The work presented in this paper proposes a viable approach for the fabrication of nanocomposites using the stir casting method, thereby offering valuable insights for further research on stir casting technology.