Insight into hexacelsian-to-celsian transformation in hot-pressed BN/BAS composites

摘要

This study aims to elucidate the phase transformation of hexacelsian-to-celsian in 10 wt.% h-BN reinforced BaAl2Si2O8 (BN/BAS) composites fabricated by hot-pressed at 1300 degrees C for different holding time. Results showed that the relationship between the transformation fraction of celsian and the holding time displays a typical "S" curve according to Johnson-Mehl-Avrami equation. During the hexacelsian-to-celsian transformation, a transitional phase of paracelsian was observed. Celsian tended to nucleate and grow up along the (110)(p) habit plane of paracelsian by a non-diffusive transition behavior. During transformation, celsian and paracelsian present an oriented intergrowth with orientation relations of (110)(p)//(020)(M), [001](p)//(101](M) and [1 (1) over bar0]p//[10 (1) over bar](M).