Nucleation and epitaxial growth of highly textured Al₂O₃–ZrO₂ nanoeutectic rapidly solidified from oxyacetylene flame remelting

The nucleation and epitaxial growth behavior of a novel Al₂O₃-ZrO₂ nanoeutectic rapidly solidified from the oxyacetylene flame remelting have been investigated. The nanoeutectic ceramic consists mainly of highly textured cellular structure with an average interphase spacing of 136 nm. Especially, a singular transition mechanism associated with “one-step cellular refining” to “two-step cellular refining” is proposed in a variable region from a coarse irregular to an ultrafine lamellar structure, and the regional undercooling is estimated to be 0.57–2.86 K. The Al₂O₃ phase nucleates as the leading phase in the rapidly solidified structure according to a quantitative calculation of nucleation rate. The cellular eutectic exhibits with a tilted feature, where its cellular growth deviates from the heat flow direction to a preferred growth orientation.