Rapid growth and formation mechanism of ultrafine structural oxide eutectic ceramics by laser direct forming

Melt growth of oxide eutectic is an important and fast-growing research topic in the fields of both applied physics and materials science. Rapid one-step fabrication of melt-grown oxide ceramics with large size is developed using laser direct forming. The near 100 density of Al₂O ₃/YAG eutectic ceramic in situ composite free of pore and cracks is rapidly melted/solidified directly from Al₂O₃-Y ₂O₃ powder without any preforming or sintering. Uniform three-dimensional network of ultrafine nanostructured eutectic microstructure is obtained. The direct experimental evidence of faceted-nonfaceted eutectic transition at high growth rate is presented and the physical model of the microstructural formation based on atom cluster elementary process is proposed. This technology provides a rapid freeform fabrication of high-performance complex shaped ceramics for various applications.