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Hybrid aluminum matrix composites have attracted researchers in the world because of their more excellent mechanical properties than metal matrix composites with single reinforcement. In this paper, TiC@TiN–Ti2N–Al4C3/Al composite was prepared by high-energy ball milling and spark plasma sintering (SPS) with Al–10Ti powders and g-C3N4 powders. TiC, TiN, Ti2N and Al4C3 reinforcements were synthesized by in situ reaction during the high-energy ball milling and SPS processing. Then, TiC@TiN–Ti2N–Al4C3/Al composite ribbons were prepared by melt spun. Next, the ribbons were added to the Al–Zn–Mg–Cu melt to prepare TiC@TiN–Ti2N–Al4C3/Al–Zn–Mg–Cu composite. It was found that TiC@TiN, Ti2N and Al4C3 reinforcements had good refining and reinforcing effects on the Al–Zn–Mg–Cu alloy. The average grain size of the composite is from ~ 95 to ~ 35 μm. Besides, there is a 14.0% increase on the ultimate tensile strength and a 21.9% increase on the elongation of the composite. The microstructure, orientation relationship and mechanical properties of the TiC@TiN–Ti2N–Al4C3/Al–Zn–Mg–Cu composite were investigated. Besides, the strengthening mechanism of the TiC@TiN core–shell structure on the composite was mainly discussed by first principles. [ABSTRACT FROM AUTHOR]

An in situ TiC–TiB2/Al composite inoculant is prepared by melt spinning the sintered mixture of Al powder, Ti powder, B4C particles, and graphene nanoplates (GNPs). To increase the degree of dispersion of the particles, the GNPs are coated on the surface of the B4C particles by high‐energy ball milling before sintering. The as‐spun inoculant ribbons are added to the melt of a typical Al–Si alloy to verify its effect of refining the grains on aluminum alloys. It is found that the columnar grains of the as‐cast Al–Si alloy sample are refined to finely approximate equiaxed grains, with an addition level of 0.6 wt% of the inoculant ribbons. The mechanical properties of the as‐inoculated Al–Si alloys also improve significantly, and show a remarkable strengthening and toughening effect. It can be attributed to the grain refinement and the dispersion strengthening by the introduction of TiC and TiB2 particles in the Al matrix. The results show that the newly developed composite inoculant ribbons using GNPs can significantly meliorate the overall mechanical performance of typical Al–Si alloys. [ABSTRACT FROM AUTHOR]