INNOVATIVE MANUFACTURING PROCESS OF MGC COMPONENTS FOR ULTRA-HIGH EFFICIENCY GAS TURBINE SYSTEMS

摘要

Much attention has been paid to unidirectionally solidified ceramic composites as candidates for high-temperature structural materials. Eutectic composites, known as Melt Growth Composites (MGCs), have recently been developed. The binary MGCs (Al_2O_3/YAG and Al_2O_3/GAP binary systems) have a novel microstructure, in which continuous networks of single-crystal Al_2O_3 phases and single crystal oxide compounds (YAG or GAP) interpenetrate without grain boundaries. Therefore, the MGCs have excellent high temperature strength characteristics, creep resistance, superior oxidation resistance and thermal stability in the air atmosphere at very high temperatures. Manufacturing processes for the MGCs are being examined under a Japanese national project, scheduled from 2001 - 2005. To achieve higher thermal efficiency for gas turbine systems, uncooled turbine nozzle vanes have been fabricated on an experimental basis. Novel manufacturing processes for MGC gas turbine components are proposed.