Characteristics and mechanical properties of magnesium matrix composites reinforced with micron/submicron/nano SiC particles

The (micron[m] + submicron[s] + nano[n]) SiC particles (SiCp) reinforced AZ31B magnesium matrix composites (AZ31B/SiCp/m + s + n composites) were fabricated by stirring casting technology followed by hot extrusion. This method has successfully solved the homodisperse problem of SiCp/m + s + n in the magnesium matrix composites. The influence of SiCp/m + s + n on the dynamic recrystallization (DRX) behavior of the magnesium matrix was investigated by researching the TEM microstructures of composites. The results indicated that the addition of SiCp/m + s + n was helpful to increase the ratio of DRXed nucleation and reduce the average grain size of matrix. The particle deformation zone (PDZ) can be formed in the vicinity of micron SiCp, while the region with high dislocation density can be created around submicron SiCp owing to pin dislocation and deformation mismatch between matrix and particles. These regions are ideal sites for the formation of recrystallization nucleus. Meanwhile, the addition of fine SiCp(nano and submicron) may delay or hinder the growth of matrix grain through the pinning effect on the grain boundaries during hot extrusion. The tensile test indicates that the strength of the AZ31B/SiCp/m + s + n composites has a significant improvement. Compared with the single sized or bimodal sized particles reinforced magnesium matrix composites, the tensile strength of the AZ31B/SiCp/m + s + n composites were highlighted. (C) 2016 Published by Elsevier B.V.