Design and In-Situ Processing of Metal-Ceramic and Ceramic-Ceramic Microstructures

In-situ composites comprising phases of the Ni-Al-O systems are selected for investigation for high temperature applications. Metal-ceramic microstructures have been synthesized in situ by a variety of novel processing techniques, including the partial reduction of oxide compounds and displacement reactions and sol-gel processing for example, the PI has formed Ni-Al-O microstructures in situ by partial reduction of NiAl-O at 1100 C. Equipment and experimental procedures have been developed for performing strength, fracture toughness, and creep experiments on small samples of metal-ceramic composites at room and elevated temperatures. Mechanical properties measurements and microstructural studies have been made with the goal of developing an understanding of the microstructural features of composites that are desirable for good mechanical properties. Micromechanical calculations are being made to develop basic rules and criteria for optimizing the mechanical behavior of the in situ processed metal-ceramic composites operating under high temperature conditions. Analytical and numerical models are being developed to simulate the deformation and calculate their statistical strength and fracture toughness properties.