High-resolution EBSD study of the microstructural evolution,grain boundary dynamics,and crystallographic texture in rare-earth-oxide–containing hybrid composites

Abstract

The development of advanced aluminium hybrid metal matrix composites (AHMMCs) reinforced with rare earth oxides (REOs) remains a concern for the research community to produce lightweight materials for many advanced engineering applications with improved mechanical characteristics. To ensure the effective manufacturing of REOs-based composites, further research into the behavior of reinforcement with the matrix microstructure following composite preparation is required, as well as which strengthening process is best suited to improving mechanical qualities. The present paper aims to investigate the reinforcement SiC/Al₂O₃/CeO₂ effect on the microstructure of Al hybrid composites prepared using stir casting. Hybrid aluminium composites contains 5 to 15% wt.% of (silicon carbide and aluminium oxide) and 0.5 to 2.5 wt.% CeO₂. The in-depth understanding of the microstructural formation mechanisms was analysed using the EBSD results. Variable mis-orientation threshold values obtained by EBSD were used to recognize the grain and subgrain structures. Low-angle grain boundaries (LAGBs) were defined within the range of 3°-15°, while high-angle grain boundaries (HAGBs) were considered as those with mis-orientation angles greater than 15°. Geometry necessary boundaries (GNBs) and LAGBs develop as a result of dynamic recovery (DRV) at tested places with minimal or moderate plastic deformation in all composites tested. The texture evolution at various locations is presented by the inverse pole figures.