Theses and Dissertations Collection

3 mole % Yttria-stabilized tetragonal zirconia polycrystalline/Magnesium aluminate spinel (3Y-TZP/MgAl2O4) nanocomposite have exhibited high strain rate superplasticity at 1.7×〖10〗^(-2)-3.3×〖10〗^(-1) s^(-1). Low strain rate superplasticity 〖(10〗^(-5)-〖10〗^(-3) s^(-1)) has been the main drawback of using superplastic ceramics in industries. Microstructural design of

3Y-TZP/MgAl2O4 composite is a key in obtaining high strain rate superplasticity within the range of〖 10〗^(-2)-〖10〗^0 s^(-1). 3Y-TZP/MgAl2O4 may experience a surge in its application at high temperature if the microstructure is designed to exhibit high strain rates at low temperatures.

In the present study, the reverse coprecipitation synthesis technique was adopted to synthesize nanocomposite powders containing 70%3Y-TZP/30%MgAl2O4 and 60%3Y-TZP/40%MgAl2O4 with microstructural characteristics suitable for superplastic application. It was expected that the coprecipitation synthesis technique route will yield highly homogeneous nanocrystalline composite powders, which could be sintered into a dense component with high thermal stability of the small grains. Microstructual features observed after processing powders of 3Y-TZP/MgAl2O4 revealed that the coprecipitation synthesis is a suitable technique for processing nanocomposite powders for superplastic application.