Mechanical Characterization of Aluminum Silicate (Al₂SiO₅)/Alumina (Al₂O₃)-Reinforced Al6082 Hybrid Metal Matrix Composites: Monotonic Tensile Strength, Fatigue, and Fractographic Investigation

Particulate-reinforced metal matrix composites (MMCs) are gaining significant importance in advanced materials research due to their superior mechanical properties and also suitability for structural applications under monotonic and cyclic loading conditions. However, limited studies reported the combined experimental and numerical investigation of monotonic tensile behavior, high-cycle fatigue life, fatigue crack propagation, and fractographic characteristics of Al6082-based hybrid MMCs reinforced with dual ceramic particulates. The present work addresses this gap by investigating the mechanical behavior of Al6082 hybrid MMCs reinforced with alumina (Al₂O₃) and aluminum silicate (Al₂SiO₅), synthesized using the stir-casting process. The influence of material composition and the process parameters on microstructure, tensile strength, fatigue life, and fracture behavior is systematically examined for different Al₂O₃ contents while maintaining Al₂SiO₅ at a constant 5 wt.%. A maximum tensile strength of 198 N/mm² was achieved for the composite containing 5 wt.% Al₂SiO₅ and 10 wt.% Al₂O₃, representing a significant improvement compared to the unreinforced Al6082 alloy and aluminum-based MMCs reported in the literature. The composites with 10-15 wt.% Al₂O₃ exhibited enhanced fatigue and fatigue crack propagation life in the range of 8.4 × 10⁶ to 1.11 × 10⁷ cycles, attributed to improved load transfer, grain refinement, and strong interfacial bonding. Fractographic analysis under monotonic and cyclic loading conditions provides valuable insights into the dominant failure mechanisms and the role of ceramic reinforcements in governing crack initiation and propagation. The outcomes of this study demonstrate the potential of Al6082/Al₂O₃/Al₂SiO₅ hybrid MMCs for fatigue-critical structural applications.