A second-generation Co-free Ni base single crystal superalloy, TMS-82C (Ni-0Co-4.9Cr-1.0Mo-8.7W-5.3Al-6.0Ta-2.4Re-0.1Hf, in mass%) was derived from its base alloy, TMS-82+ (Ni-7.8Co-4.9Cr-1.9Mo-8.7W-5.3Al-6.0Ta-2.4Re-0.1Hf, in mass%), which had been successfully engine tested. The absent of Co can eliminate the product of isotope 60Co from radioactive decay, and it can improve the maintainability of the gas turbine engine. However, the removal of Co had decreased the creep strength of TMS-82C. To further improve its creep strength, five additional alloys were designed with the addition of 0.5 mass% Mo, W, Ti, Ta and Re to TMS-82C, respectively. Results indicated that creep properties of all five alloys performed better than that of TMS-82C under 900°C/392 MPa and 1000°C/245 MPa conditions. W-bearing alloy exhibits similar creep property comparing to that of TMS-82+ under the 900°C/392 MPa condition.
