Enhanced Elevated-Temperature Tribological Properties and Microstructure of Co-continuous Iron Foam/SiC/Al-Si Dual-Reinforced Composites Fabricated by Vacuum-Assisted Infiltration

Al-9Si-0.6Mg matrix composites dual-reinforced with 20 wt.% SiC particles and three-dimensional iron foam (iron foam/SiC/Al-Si) were fabricated using vacuum semi-solid stirring and vacuum-assisted infiltration. The tribological behavior at elevated temperatures was investigated under different loading conditions. The dry sliding wear test revealed that the three-dimensional interpenetrating iron foam skeleton contributes to improved wear performance at elevated temperatures, owing to an increase in surface hardness and decrease in subsurface wear deformation caused by the bearing capacity and synergistic strengthening effect of iron foam during the sliding process. SEM analysis of the longitudinal section of the friction-affected layer of the iron foam/SiC/Al-Si composite demonstrated that the formation of a mechanically mixed layer can decrease wear loss. Wear rate, wear morphology, and debris morphology were correlated with wear mechanisms. The increased load promotes the propagation of horizontal cracks and delamination wear. The predominant wear mechanisms of the iron foam/SiC/Al-Si composite change from abrasive wear and a small amount of oxidation wear to delamination, adhesive wear, and plastic flow when the temperature reaches 350 °C.