INITIAL INVESTIGATION OF CARBIDE-TYPE CERAMAL OF 80-PERCENT TITANIUM CARBIDE PLUS 20-PERCENT COBALT FOR USE AS GAS-TURBINE-BLADE MATERIAL

摘要

An investigation vas conducted to deteimine the material problems arising in the use of a carbide-type ceramal for gas-turbine blades. Specimens of an 80-percent titanium carbide plus 20-percent cobalt (by weight) ceramal were investigated for short-time tensile-strength characteristics at 1800° and 2200℉ and for thermal-shock characteristics at 1800°, 2000°, 2200°, and 2400℉. Gas-turbine blades of this material were operated in a quasi-service-evaluation unit. The conditions of operation were indicated inlet-gas temperatures between 1700° and 2200℉ and turbine tip speeds between 478 and 835 feet per second. A commercial tensile machine, a specially designed fur¬nace and air-quench-chamber apparatus, and a small gas turbine were used for these investigations. X-ray-diffraction studies were made of the material before and after operation in the form of turbine blades. For comparison purposes, zircon and titanium carbide ceramics and an alloy were investigated for thermal-shock; characteristics and turbine-blade performance, respectively.