Microstructure phase distribution analysis of Al-Si-TiB_2-Sr-Sc composite fabricated by casting technique

摘要

The aluminium-silicon (Al-Si) alloys, based on the Metal Matrix Composites (MMCs) system are widely used in light-weight constructions and transport applications requiring a combination of high strength and ductility. A grain refinement plays a crucial role in improving characteristics and properties of Al-Si alloys. In this investigation, titanium diboride (TiB_2), scandium (Sc) and strontium (Sr) elements were added to the aluminium alloys for grain refinement of the alloy. This study focused more on how to improve the microstructure of the alloy by adding some inoculants that mentioned above. The TiB_2 content was fixed at 6wt.% while 0.2-0.8wt.% Sc and Sr contents were chosen in this investigation. Characterizations of the alloy by using X-ray Diffraction (XRD) and Field Emission Scanning Electron Microscope (FESEM) were conducted to identify how the inoculants existence affected the phase composition and the microstructure of composite. From the results obtained, it showed that the hardness of the alloy increased compared to Al-Si-TiB_2-Sr alloy without addition of Sc. The study discovered that the inoculants can act as a grain refiner due to decrement size of dendritic structure and also responsible for the mechanical properties improvement.