Formation mechanism of a wrinkled and textured Al2O3-ZrO2 nanoeutectic rapidly solidified from oxy-acetylene flame remelting

Abstract

A highly wrinkled and textured Al2O3-ZrO2 nanoeutectic induced by oxy-acetylene flame remelting was elaborated for the first time from the perspective of morphological evolution and formation mechanism. The rapidly solidified Al2O3-ZrO2 ceramic exhibits a wrinkled cellular nanoeutectic structure with a minimum interphase spacing of 0.12 μm. The Jackson-Hunt (JH) eutectic theory is more appropriate to predict the growth of Al2O3-ZrO2 nanoeutectic induced by oxy-acetylene flame remelting than the Trivedi-Magnin-Kurz (TMK) model. The bulk growth rate of 7.8 μm3/s is close to the theoretically predicted value of 11.0 μm3/s by the JH model. The eutectic growth rates of Al2O3-ZrO2 with average interphase spacings of 0.12 and 0.3 μm are estimated to be 763.8 and 122.2 μm/s, respectively. Especially, a mesoscopic insight into formation mechanism of the wrinkled and textured eutectic was proposed from a three-dimensional perspective based on both the crystal growth orientation and the airflow effect.