Study on Friction Properties of In Situ Synthesized (AlB2 + Al2O3)/A356 Composite

In this paper, we designed the A356-B2O3-KBF4 reaction system to synthesize (AlB2 + Al2O3)/A356 biphasic particles-reinforced aluminum matrix composite with varying weight percentages (2%, 4%, 6%, and 8%). The synthesis was achieved through mechanical mixing and mixed salt reaction. We studied the friction and wear performance of the composite at room temperature using XRD, PC, SEM, EDS, laser confocal microscopy, and microhardness analysis. Our results indicate that the AlB2 and Al2O3 duplex-enhanced particles were effectively synthesized, with predominantly short rod morphology and local clustering observed for the AlB2 particles. The AlB2 particles were mostly in the micron-scale range, while the Al2O3 particles were mostly in the nanoscale range, both exhibiting agglomeration phenomena. Both enhanced particles showed an agglomeration phenomenon and could grow together with the interface binding very closely. At 6 wt.% mass fraction of biphasic particles, the composite exhibited the best refinement effect on-Al grains, as well as the greatest friction reduction effect and wear resistance for both the (AlB2 + Al2O3)/A356 composite and the A356 matrix alloy. The wear mechanism was primarily abrasive wear, while the A356 matrix alloy's wear mechanism was adhesive wear.