Mechanical Properties of Al-Si Alloy-Based Composites Reinforced by in-situ TiB_2 Particulates

摘要

Al-Si alloy-based composites are widely used in automotive, aerospace and mineral processing industries with improved properties. In situ techniques have been developed to fabricate Al-Si alloy-based composites, which can lead to better adhesion at the interface and hence better mechanical properties. Al-Si alloy reinforced with in situ TiB2 particles was synthesized successfully by using salt reaction route. These in situ composites have shown significant improvement in mechanical properties compared with the base alloy. The wear resistance of the alloy is also significantly improved with the addition of TiB_2 particles. The hardness, strength and wear resistance are strengthened with increasing TiB_2 content of the composites. TiB_2 can act not only as a grain refiner for primary Al but also as a modifier of Si in eutectic mixture. Analysis of the worn surface of Al-Si/TiB_2 composites tested under loads of 30 and 110N suggests that ploughing is predominant at lower loads and delamination is predominant at higher loads.