Identification of novel dual-scale Al3BC particles in Al based composites

•Al3BC is firstly used as a strengthening agent for aluminum based composites.•Al3BC reinforced Al based composites are in-situ fabricated by liquid–solid reaction method.•Dual-scale Al3BC particles with sizes of 100–300 nm and 5–20 nm distribute homogeneously in the matrix.•Dual-scale Al3BC has promising strengthening effects on the aluminum alloy matrix.•The synthesis mechanisms of Al3BC particles in Al–B–C system are discussed.

In this work, the Al3BC/Al (Al–3Cu) composites have been firstly in-situ fabricated by liquid–solid reaction method. The microstructures of the samples were investigated by X-ray diffraction (XRD), scanning electron microscope (SEM) and transmission electron microscope (TEM). Two typical sized Al3BC particles of 100–300 nm and 5–20 nm have been in-situ fabricated, and the particles show the uniform distribution. Mechanical property tests reveal the remarkable coordinated enhancement effects of dual-scale Al3BC particles. The hardness, tensile strength and abrasion resistance of 26% Al3BC/Al–3Cu composite are improved by 106.3%, 143.5% and 27.3% respectively, compared with the unreinforced alloy. The synthesis mechanisms of Al3BC are also discussed and two different mechanisms are proposed to explain the formation of the dual-scale particles.

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