Simultaneously improving strength and ductility of hybrid Al–Si matrix composite with polyphasic and multi-scale ceramic particles

Highlights: • In situ polyphasic and multi-scale particles was prepared by PM and melt-spinning. • Inoculant ribbons refine the α-Al grain and optimize the morphology of eutectic silicon. • VB₂–AlN–Al₄C₃–VSi₂/Al interface is clean and well lattice-matched. • The VB₂–AlN–Al₄C₃–VSi₂/Al–12Si composite exhibit excellent mechanical properties. Hybrid aluminum matrix composites have received widespread attention because of their superior performance to single-phase reinforced aluminum matrix composites. In situ VB₂–AlN–Al₄C₃–VSi₂/Al ribbons with polyphasic and multi-scale reinforcement particles were prepared by powder metallurgy method and controlled by melt-spinning and then verified the reinforcement efficacy in Al–12Si alloy. It was found that the addition of VB₂–AlN–Al₄C₃–VSi₂/Al ribbons not only refined the grain of α-Al, but also optimized the morphology of eutectic silicon for Al–12Si matrix composite. Thereafter, the mechanical properties of the VB₂–AlN–Al₄C₃–VSi₂/Al–12Si composite, including the tensile strength, ductility and hardness were increased by 36.2%, 82.2% and 33.4%, respectively, with the addition of VB₂–AlN–Al₄C₃–VSi₂/Al ribbons. The excellent mechanical properties can be attributed to the micron-sized VSi₂ particles, nano-sized AlN, VB₂, and Al₄C₃ as well as the well-bonded particle/matrix interface. In addition, multiple strengthening mechanisms have also made outstanding contributions to the improvement of the mechanical properties, including (1) Orowan strengthening; (2) Coefficient of thermal expansion (CTE) mismatch strengthening; (3) the Hall-Petch effect caused by grain refinement. The present experimental results provide an insight into the understanding of polyphasic and multi-scale reinforcement particles, and extend the effort for the development of Al–Si composite.