Improved Silicon Nitride For Advanced Heat Engines
Report summarizes results of four years of research directed toward increasing strength and reliability of injection-molded silicon nitride parts for advanced heat engines.
Yeh, Harry C.↗
Engineering topics
Yeh, Harry C.
Publications and source records attributed to Yeh, Harry C..
Improved silicon nitride for advanced heat engines
The results of a four year program to improve the strength and reliability of injection-molded silicon nitride are summarized. Statistically designed processing experiments were performed to identify and optimize critical processing parameters and compositions. Process improvements were monitored by strength testing at room and elevated temperatures, and microstructural characterization by optical, scanning electron microscopes, and scanning transmission electron microscope. Processing modifications resulted in a 20 percent strength and 72 percent Weibull slope improvement of the baseline material. Additional sintering aids screening and optimization experiments succeeded in developing a new composition (GN-10) capable of 581.2 MPa at 1399 C. A SiC whisker toughened composite using this material as a matrix achieved a room temperature toughness of 6.9 MPa m(exp .5) by the Chevron notched bar technique. Exploratory experiments were conducted on injection molding of turbocharger rotors.
Yeh, Harry C.↗