LAUSR

Abstract n-SiCp/AZ91D magnesium matrix nanocomposites show the high strength and relatively good plasticity after T6 ageing treatment. In this study, optical microscope (OM), scanning electron microscope (SEM) and transmission electron microscope (TEM) were used to study the interaction of nanoparticles and dislocations with β-Mg17Al12 precipitates in n-SiCp/AZ91D-T6 nanocomposites. The experimental results show that SiC nanoparticles have a certain influence on the morphology, size and distribution of β-Mg17Al12 precipitates, which make the precipitates finer and more disperse, thus giving full play to the precipitation strengthening effect of the secondary precipitation phases. A large number of dislocations occur around the nanoparticles and the precipitates in the plastic deformation process. The dislocations tangle around the precipitates when the dislocations with different orientations encounter, and some dislocations leave the dislocation sinks after cutting through the Mg/Mg17Al12 interfaces. Refinement of matrix and precipitate phase grains, entanglement of dislocations and formation of dislocation sinks are the main reasons for the high strength and good plasticity of n-SiCp/AZ91D nanocomposites after T6 ageing treatment.