Microstructural characteristics and mechanical behaviour of aluminium matrix composites reinforced with Si-based refractory compounds derived from rice husk

The microstructural characteristics and mechanical behaviour of aluminium matrix composites reinforced with Si-based refractory compounds (SRC) derived from rice husk were investigated. The reinforcement materials (SRC) were synthesized using a carbothermal processing technique. The reinforcement was used to prepare a 10 wt.% Al-Mg-Si alloy-based composite using a double stir casting process. The composites produced were characterized using microhardness, tensile properties, scanning electron microscopy (SEM), and X-ray diffractometer (XRD). From the results, A1650, C1650, and A1600 grades of the samples show more resistance to indentation due to the high proportion of hard SRC in the reinforced materials. Superior elongation values were observed for these composites A1650, C1650 and A1600 grades, respectively. The grades A1250, B1250, and C1250 series had the least toughness values within the range of 20-37% as compared to the control sample. For all composites under examination, the percent porosity was noted to be less than 4% and the strain to fracture was within 24-38%. Higher intensity of SiC was observed from the XRD spectrum and the formation of intermetallic materials. The tensile fracture surface morphologies of the composites produced were similar, showing a ductile dimple-like structure. The formation of a micro-crack and micro-void was also observed along the interphase.

Automated summary

The study found that aluminium matrix composites reinforced with Si-based refractory compounds (SRC) derived from rice husk showed superior fire resistance and high elongation and hardness. Composites with lower toughness values were mainly in the A1250, B1250, and C1250 series, with porosity less than 4% and strain to fracture ranging from 24-38%. The XRD spectrum revealed higher intensity of SiC and the formation of intermetallic materials, while the tensile fracture surface of the composites displayed a ductile dimple-like structure with micro-cracks and voids at the interphase.