Fundamental Structure-Property Relationships for High-Temperature Ceramic Composites

摘要

This research program focused on studying interface structure and thermal compatibility stresses in several directionally solidified eutectic ceramic materials, which are candidates for high-temperature and ultra-high temperature structural materials in aerospace applications. Under this award we specifically investigated the alumina-zirconia and lanthanum hexaboride- zirconium diboride eutectic systems. High-resolution transmission electron microscopy was utilized to understand interfacial structures in these materials and x-ray diffraction was utilized to measure thermal residual stresses. A major conclusion of the research program was that thermal stresses are the dominant factor that leads to the high fracture toughness in the lanthanum hexaboride-zirconium diboride eutectic systems. The research program supported two Ph.D. students and two undergraduate students.