Sliding Wear Behaviour of In Situ TiB2 Reinforced Hypoeutectic Al-Si Alloy Composites

The wear behaviour of the Al-7Si alloy was investigated in this study under various in situ TiB2 reinforcements (3, 5, and 7 wt%). These composites were made by reacting molten Al-7Si alloy with a combination of KBF4 and K2TiF6 at an 800 °C reaction temperature. Stir casting was used to evenly distribute TiB2 reinforcing particles in the Al-7Si alloy. The microstructure, worn surface, and phases of both matrix and composites were described using an optical microscope (OM), scanning electron microscopy (SEM), and EDS, respectively. The findings reveal the presence of a dendrite Al phase and a needle shape of eutectic Si phase in matrix alloys. The microstructure of the composites reveals homogeneous dispersion of TiB2 particles, grain refined Al, and eutectic Si phase in a short-rod shape. With an increase in TiB2 concentration, there was significant refinement in Al and a reduction in interspaced between eutectic silicon. The microhardness of base and composites containing various amounts of TiB2 was investigated. It was observed that the hardness of composites increases as the weight % of TiB2 increases when compared to matrix alloy. When compared to matrix alloy, the Al-7Si -7TiB2 composite had a nearly 45% higher hardness. Dry sliding at loads of 10, 20, 30, and 40 N with sliding velocities of 1, 2, and 3.0 m/s was used to investigate the wear characteristics of the base alloy and composites. . The wear rate was shown to decrease under all operating settings with greater TiB2 concentration, according to the findings. Abrasion and de-lamination were the dominating mechanisms at higher loads and sliding speeds.