High-Temperature Friction Wear Behavior of (AlB2 + Al2O3)/A356 Composites Regulated by Acoustic-Magnetic Coupling Field

In this paper, the A356-B2O3-KBF4 system was designed, and (AlB2 + Al2O3)/A356 in situ dual-phase reinforced particle composites with mass fractions of 2 wt%, 4 wt%, 6 wt% and 8 wt% were prepared by the DMR method. The acoustic-magnetic coupling control was carried out during the preparation of 6 wt% (AlB2 + Al2O3)/A356 composite. XRD, PC, SEM, EDS, and dry friction tests studied the composites' microstructure and high-temperature wear properties. The results show that the matrix alpha-Al grains of the composite are refined under the action of the coupling field, with a grain size of: 94.3 um. The AlB2 particles are rod-shaped with a radial size of 11 um, and the Al2O3 particles are nano-sized flakes. The wear mechanism of (AlB2 + Al2O3)/A356 dual-phase in situ aluminum matrix composites is high-temperature oxidation abrasive wear, which differs from the adhesive wear of the matrix alloy. Due to the anti-friction, lubrication and anti-wear effects of the dual-phase in situ particles (AlB2 + Al2O3), the wear resistance of the composites is improved, and the coefficient of friction is reduced by 13.4% compared to the A356 matrix alloy. With the increase in temperature, the wear resistance of 6 wt% (AlB2 + Al2O3)/A356-1 kW-10 Hz composite was substantially better than that of the A356 matrix alloy. The wear rate of the composite at different temperatures was reduced by 8.82% (100 C-degrees), 11.29% (200 C-degrees), and 13.69% (300 C-degrees), respectively, compared with that of the matrix A356.