Creep Rupture Behavior of Selected Turbine Materials in Air, Ultra-High Purity Helium, and Simulated Closed Cycle Brayton Helium Working Fluids

Five turbine materials, IN100, 713LC, MAR-M-509, MA-754 and TZM were selected as candidate materials for use in a Compact Closed Cycle Brayton System (CCCBS) study in which helium served as the working fluid. The suitability of the alloys to serve in the CCCBS environment at 927 C (1700 F) was evaluated on the basis of creep-rupture tests conducted in air, ultra-high purity helium (>99.9999 percent), and a controlled impurity helium environment. Baseline reference creep rupture properties for times up to 10,000 hr were established in a static ultra-high purity helium environment.