Development of Novel Ni–Co Base P/M Disk Superalloy by Redesigning Based on Turbine Blade Alloy TM-47

The temperature capability of current state-of-the-art high-pressure diskDisk superalloysSuperalloys is around 700 °C. To further improve their temperature capabilities, new diskDisk alloy designAlloy design approaches with a focus on blade alloy compositions, which was designed for applications at temperatures of above 900 °C or higher, may be effective. In this study, novel Ni–Co base diskDisk superalloysSuperalloys were designed based on a combination of Ni-base blade superalloySuperalloys TM-47 and Co-12.5 wt.% Ti, both of which possess a γ–γʹ two-phase structure. First screen results using single crystalSingle crystal casts revealed TM-47 to be a potentially promising candidate as a base alloy for Ni–Co base diskDisk superalloySuperalloys, while additions of Co-12.5 wt.% Ti to TM-47 was found to improve creepCreep strength of the alloy. A later investigation using P/M alloys revealed that limited additions of Co-12.5 wt.% Ti to the base alloy also improves powder manufacturability, phase stability, and high temperatureHigh temperature proof stress. Thus, TM-47 M2 (20 wt.% addition of Co-12.5 wt.% Ti to TM-47) was selected as a candidate alloy for subscale manufacturing trial. CreepCreep tests at 760 °C/630 MPa demonstrated that the selected TM-47 M2 provides superior creep propertiesCreep properties compared to other conventional diskDisk superalloysSuperalloys, especially for the 0.2% creepCreep time, which is a critical property for high-pressure turbine disksDisk.