Tensile and wear behaviour of in situ Al-7Si/TiB₂ particulate composites

Abstract

Al-7Si 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 in comparison to the base alloy. The wear resistance of the alloy also significantly improved with the addition of TiB₂ particles. The hardness, strength and wear resistance increased with increasing TiB₂ content of the composites. TiB₂ appears to not only act as a grain refiner for primary α-Al but also as a modifier of Si in eutectic mixture. The mechanical properties of the present Al-Si/TiB₂ composites are better than those reported earlier with SiC reinforcement. Analysis of the worn surface of Al-Si/TiB₂ composites tested under normal loads of 40 and 120 N suggests that adhesion and ploughing are predominant at lower loads and delamination is predominant at higher loads.