BaZrO3 refractory applied to the directional solidification of TiAl alloys

Abstract

Recently, much attention has been paid to the refractory used for the directional solidification process of TiAl intermetallics, the Y2O3 crucible/Y2O3 coated moulds seem to be the suitable candidate. However, the use of Y2O3 is limited by its low thermal shock resistance and high cost. In this work, a novel BaZrO3 refractory was introduced to the directional solidification of TiAl intermetallics. The melt of this alloy contained in BaZrO3 crucibles were heated for 30 minutes at 1600, 1650, 1700 °C, respectively, then cooled within the crucible for the investigation of the interface between the melt and the refractory. The scanning electron microscopy (SEM) was used to evaluate the surface topography and microstructure of the samples, and the energy dispersive spectroscopy (EDS) was used to analyse the chemical composition of the samples. The results indicated that no interfacial interaction layer and no obvious element diffusion were observed between the crucible and the metal, which may imply that the BaZrO3 is a promising candidate of refractory for the directional solidification of TiAl alloys. This work can provide a basis for the further study of directional solidification of TiAl alloys by using BaZrO3 shell mould.