2003 Volume 44 Issue 9 Pages 1690-1693
The microstructure and crystallographic texture of a directionally solidified Al2O3/YAG eutectic composite were studied by field emission scanning electron microscopy (FE-SEM), electron backscatter pattern (EBSP) method and X-ray diffraction (XRD). The high-temperature strength of the composites was investigated by compression test. The Al2O3/YAG eutectic composite with characteristic microstructure shows highly accumulated texture with preferred growth orientations of 〈300〉 for Al2O3 and 〈420〉-〈800〉 for YAG. The growth directions of Al2O3 are concentrated around 〈100〉 and 〈010〉 directions in twin-related variants, along the interphase boundaries. The composite strength is dependent on both compression direction and strain rate at 1773 and 1873 K, which is attributable mainly to the strain rate and orientation dependence of strength for constituent Al2O3.