Abstract:The recrystallization nucleation processes of two cold-rolled Al-Mg-Si/SiC_p composites with different contents of Mg are investigated mainly by dynamic mechanical analyzer (DMA) and electron microscopy including high angle annular dark field scanning transmission electron microscopy (HAADF-STEM) and high-resolution transmission electron microscopy (HRTEM). Internal friction and electron microscopy results show that solute atom clusters are present in association with dislocations in supersaturated cold-rolled composites. During recrystallization process, the internal friction peak position of Al-Mg-Si/3SiC_p/2Mg (volume fraction, %) is higher than that of Al-Mg-Si/3SiC_p (volume fraction, %) due to more solute atom clusters formed in association with the dislocations in the cold-rolled composite with a much higher Mg content, indicating a stronger resistance for the recrystallization nucleation.

Key words: aluminum matrix composites; recrystallization; internal friction; dislocation; microstructures；transmission electron microscopy;