Advanced turbines with improved efficiency require materials that can operate at higher temperatures. Availability of these materials would minimize cooling flow requirements, and, thus, improve the efficiency of a turbine. Advanced processing. such as directional solidification (DS), can improve temperature capability of the majority of Ni based superalloys. However, results of earlier work on IN-738 reveal that the DS process does not significantly improve temperature capability of this alloy. A research program was initiated to develop a corrosion resistant Ni-based DS blade material for land based turbines. In this program, eight heats with varied Cr, Al, Ti, Ta, and W contents were selected for evaluation. Screening tests performed on these heats in the DS condition include tensile, creep, and corrosion. The Results of experimental heats were compared with those of IN-738 in the equiaxed condition. From these results, two chemistries offering approximately 100°F temperature advantage at typical row I turbine blade operating stress were selected for castability and further mechanical property evaluation. Several row 1 solid and cored turbine blades were successfully cast. The blades were evaluated for grain structure and mechanical properties. Tests were also conducted to evaluate the effects of withdrawal rates on properties. These results are summarized in this paper.

Bannister, R. L., Cheruvu, N. S., Little, D. A., and McQuiggan, G., 1994, “Development of Requirements for an Advanced Gas Turbine System,” ASME Paper No.94-GT-388.
Beck, G., 1983, “Evaluation of DS IN-738 Material,” unpublished work, Westinghouse Electronic Corporation, Orland, Florida.
Caruel, F., et, al., 1996, “Snecma Experience With Cost Effective DS Airfoil Technology Applied Using CM 186LC® Alloy,” ASME Paper No. 96-GT-493.
Cheruvu, N. S., and Roan, D. F., 1995, “Directionally Solidified and Single Crystal Blades For Land Based Turbines,” Presented at TMS-AIME Fall Meeting/ASM Materials Week, Oct. 29-Nov. 2, 1995, Cleveland, Ohio.
Farmer, R., and Fulton, K., 1995, “Design of 60% Net Efficiency in Frame 7/9H Steam Cooled CCGT,” Gas Turbine World, May, pp. 12–20.
Matsuzaki, H., et al., 1996, “New Advanced Cooling Technology and Material of the 1500°C Class Gas Turbine,” ASME Paper No. 96-GT-16.
McLean, M., 1983, Directionally Solidified Materials or High Temperature Service, The Metals Society, 1 Carlton House, London SW1Y 5DB, pp. 153.
McQuiggan, G., 1996, “Design for High Reliability and Availability in Combustion Turbines,” ASME Paper No. 96-GT-510.
Pallotta, A. A., and Srinivasan, V., 1993, “Trends in Combustion Turbine Materials and Coatings Westinghouse Perspective,” presented at EPRI Workshop, Palo Alto, California, Oct., 1993.
Sato, M., et, al. 1994, “High Temperature Demonstration Unit for a 1500°C Class Gas Turbine,” ASME Paper No. 94-GT-412.
Sato, M., et, al, 1995, “High Temperature Demonstration Unit for a 1500°C Class Gas Turbine,” ASME Paper No. 95-GT-365.
Sims, C. T., Stoloff, N. S., and Hangel, W. C., 1987, Superalloys II, John Wiley & Sons, New York.
Schneider, K., 1990, “Advanced Blading,“ Proceedings of COST 501 and 505 Conference on High Temperature Materials For Power Eng.:Part II,” Kluwer Academic Publishers Group, Boston, MA, pp. 935.
Yamamoto, Y., 1995, “Material Evaluation of Large Single Crystal and Directionally Solidified Bucket Castings for Advanced Land-Based Gas Turbines,” ASME Paper No. 95-GT-449.
This content is only available via PDF.
You do not currently have access to this content.