An EBSD study on microstructure and texture development in graphene-reinforced Al–Mg–Si nanocomposites via FSP

Abstract

This study investigates the microstructure evolution and texture development of friction stir processed (FSP) AA6061-T6 Al–Mg–Si matrix composites reinforced with graphene nanoplatelets. Using electron backscatter diffraction (EBSD), we studied changes in grain boundary characteristics and texture components. As heat input increases, the Zener-Hollomon parameter decreases, causing grain size to grow. Particles, including those of Fe-rich and Mg2Si nature, also coarsen from average sizes of 0.9–1.4 μm, and 0.2–0.5 μm, respectively. Higher heat input and plastic strain lead to a reduction of the fraction of low-Σ boundaries, while increasing high-Σ boundaries suggest activation of other deformation mechanisms, i.e., from dislocation slip to twinning, respectively, as a function of dislocation generation and recovery kinetics. Grain orientation spread (GOS) and kernel average misorientation (KAM) values also decrease, indicating a higher homogeneity and smaller local disorientations under the excess heat. The higher texture indices observed in the composite samples suggest that frictional heat and graphene addition collectively enhance preferred orientations, potentially leading to higher anisotropy. Principal texture components shift from {101}, {1‾2‾3}, {111}, {332}, {013}, and {214} in the base metal to {011}, {011}, and {112} in composites. Components such as {101} remains unaffected.

Keywords

• Friction stir processing (FSP)
• Aluminum matrix composite (AMC)
• Graphene
• Electron backscatter diffraction (EBSD)
• Microstructure
• Grain boundary