Study on the microstructural and texture evolution of Hot Rolled Al7075/ graphene/ carbon nanotubes reinforced composites

Abstract

Hot rolling (95% reduction in thickness) was applied on the Stir Cast and Hot Rolled Al7075 matrix composites reinforced with graphene nanoplates (GNPs) and carbon nanotubes (CNTs). The effects of reinforcements on the microstructural and texture evolution of hot rolled composites were studied. Scanning electron microscope (SEM) revealed that reinforcements were elongated parallel to the rolling direction. Energy dispersive X-ray spectroscopy (EDS) from the black elongated phases shows a high fraction of carbon and it confirms that they are clusters of GNPs and CNTs (depends on the sample) and second phase precipitates are AlXFe (X: 3, 6). Electron backscatter diffraction (EBSD) was employed for microstructure characterization and texture evolution of composites. According to inverse pole figure (IPF) maps, in all composites the majority of grains were elongated parallel to roll direction. According to grain orientation spread (GOS<2°) maps, addition of GNPs and % CNTs lead to stimulate the occurrence of recrystallization in the matrix. The grain orientation spread (GOS<2°) maps near the clusters of reinforcements revealed that particle stimulate nucleation (PSN) occurred in the interface of matrix/reinforcements. By presence of GNPs and CNTs in the Al7075 matrix a different texture evolution during hot rolling of prepared composites were observed.