In-situ observation of interaction between dislocations and carbon nanotubes in aluminum at elevated temperatures

In this study, in-situ high-temperature transmission electronic microscopy is performed to investigate the formation mechanism of high-fraction (>50%) low-angle grain boundaries (LAGBs) in carbon nanotubes/aluminum (CNTs/Al) composites with balanced strength and ductility. During heating up the low-temperature-sintered composite, we find that dislocation bands first moves and then they are pinned by CNTs to form LAGBs. Abundant dislocations in the Al matrix and large-aspect-ratio CNTs are clarified as two critical factors for producing LAGBs. This study provides new insight into the effect of CNTs on the microstructural and mechanical properties of metal matrix composites.