The in-situ fabricated Al2O3/SiO2(p)/Al composites were produced by adding different quantities of SiO2 particles (viz. 0, 3, 6 and 9 wt.%) into molten commercial purity Al at 750 degrees C. Newtonian thermal analysis was conducted to investigate the solidification behaviors of these molten 'composites prepared by the stir casting process. The microstructure and phase identification were achieved via optical microscope, SEM (equipped with EDS) and X-ray diffraction. Results showed the dendrite arm spacing of alpha-Al grain decreased with the increase of SiO2 addition. The SEM image showed the special duplex phase with Al2O3 layer formed around SiO2 particle in Al matrix. The Si concentration in Al matrix increased with increasing in the SiO2 addition, resulting in the decrease of liquidus temperature of the melts. Compared with the purity Al melt, one more stage related to the exothermic Al-Si phase transformation was revealed in the cooling curves of these molten composites. Cooling rate of the purity Al melt was lower than that of the melts with SiO2 particles addition. The difference in solidification behaviors of these melts was ascribed to the effect of SiO2/Al reaction on the effective heat capacity and different amounts of latent heat released from phase transformation process. (C) 2016 Elsevier B.V. All rights reserved.