Y. Waku (Sp), HPGT Research Association, Ube City (Japan); N. Nakagawa, Ube Industries, LTD., Ube City (Japan); K. Kobayashi, Ishikawajima-Harima Heavy Industries, LTD., Tokyo (Japan); K. Hirano, National Institute of Advanced Industrial Science and Technology, Ibaraki (Japan)
We have recently developed eutectic composites, which are named as Melt Growth Composites (MGCs). The binary MGCs (Al2O3/YAG and Al2O3/GAP binary systems) have a novel microstructure, in which continuous networks of single-crystal Al2O3 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. In this paper, high temperature characteristics such as high temperature strength, creep resistance, oxidation resistance and thermal stability of microstructure are briefly introduced. To achieve higher thermal efficiency for gas turbine systems, MGC bowed stacking nozzle vanes have been fabricated on an experimental basis. The steady state temperature and thermal stress distribution on the surface of the bowed stacking nozzle have been analyzed. Novel manufacturing processes for MGC gas turbine components are proposed.
