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

The application of mu-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 mu m 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 lambda v(p)(1/2) = constant = 10, where lambda has the dimension mu m and v(p) - mu m/s. (C) 1999 Elsevier Science B.V. All rights reserved.