1989 Volume 75 Issue 6 Pages 956-963
A ten-year R & D program to develop advanced gas turbines had been carried out by Agency of Industrial Science and Technology, government research institutions, and Engineering Research Association for Gas Turbines. The ultimate thermal efficiency to be attained in a combined cycle plant was 55% (LHV), for which a high pressure turbine was operated at the gas temperature up to 1400°C. One of the elements to bear this burden was the application of new turbin blade materials with columnar grained structure made through directional solidification (DS). A DS alloy TMD-5 was developed in the advanced turbine program in which:
(1) DS castability experiments were conducted for the alloy development to obtain blades with complex internal channel for cooling, and it was concluded that the γ' precipitate volume should be at about 58% balanced with optimized mechanical properties.
(2) Various mechanical properties such as tensile strength, creep strength, high cycle and thermal fatigue strength and physical properties of TMD-5 were tested, and found to be superior to those of a commercialy available DS alloy with the equivalent degree of anisotropy.