Effect of the surface preparation techniques on the EBSD analysis of a friction stir welded AA1100-B4C metal matrix composite

Characterisation of the microstructure of aluminium based metal matrix composites (MMCs), which have been used in various automobile, aerospace and military industries, remains a challenge. The grain structure in the matrix of B4C particulate reinforced MMCs and their friction stir welds was characterised using optical metallography and electron backscatter diffraction (EBSD). Optical metallography can partially reveal the grain structure in the matrix of AA1100-16 vol% B4C composites. EBSD was used to characterise the grain structure in the AA1100-16 vol% B4C friction stir welds, providing a powerful tool to monitor the microstructural evolution of MMC materials during friction stir welding. Both mechanical polishing and ion beam polishing were used for EBSD sample preparation. The effect of the sample preparation on the EBSD data acquisition quality was studied. Some typical examples, such as the identification of grains and subgrains, grain size distribution, deformation fields and the texture components are given.