Microstructure of Al₂O₃/Y₃Al₅O₁₂ eutectic fibers grown by μ-PD method

The application of μ-PD method to fiber growth of Al₂O₃/Y₃Al₅O₁₂ eutectic made possible to grow completely homogeneous, high-purity samples and to investigate the formation of eutectic microstructures under high solidification rates. Eutectic fibers of Al₂O₃/Y₃Al₅O₁₂ 0.25-1.5 mm in diameter and 500 mm in length free of grains, pores and cracks have been grown over a wide range of pulling rate 0.15-10.00 mm/min, using 4N purity starting materials. The development of characteristic eutectic microstructures in relation to pulling rate has been analyzed. Fine 'Chinese script' lamellae dispersion having interlamellar spacing less than 1 μm were completed throughout the entire cross-section of grown fibers with excellent reproducibility. The interlamellar spacing agrees with the inverse-square-root dependence on pulling rate according to λν_p^1/2 = constant = 10, where λhas the dimension μm and ν_p - μm/s.