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

Abstract

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.