Evaluation of Microstructure and Mechanical Properties of TiO2 Reinforced Aluminium Composites Developed Through Multi-Step Stir Casting

The present paper investigates the effect of TiO2 particles on the microstructure and mechanical properties of AA2014 composites. AA2014 composite samples reinforced with varying amounts of TiO2 in the range of 1–4 wt% to matrix were developed through multi-step stir casting. The mechanical properties of the developed composites and their corresponding microstructures were correlated. The microstructures revealed that TiO2 has promoted grain refinement from dendritic to globular grains through nucleation across the AA2014 matrix due to high rate of solidification which increased with an increase in the TiO2 content. The TiO2 reacted with Al to form Al2O3 in the matrix besides Al2CuMg, Al2Cu secondary phases which provided additional strength to the composites. The composite sample reinforced with 4 wt% TiO2 exhibited the best combination of mechanical properties. However, improvement in the mechanical properties beyond 3 wt% TiO2 addition was not significant.