Superalloy MMC Components for Advanced Turbine Systems

Advanced Ultra-Super Critical (A-USC) boiler will use nickel based alloys and will operate in the range of 700-760 °C (5000 psi). Advanced turbine and boiler component manufacturing process by conventional process are comprised of multi steps, turbine components are fabricated by conventional machining from a forged or rolled billet processed from an ingot which is originally made from casting/ingot metallurgy. As a result a long lead time is needed and part acquisition time is high. Low cost fabrication process is needed to replace current forging and machining processes to produce large turbine components of equal or improved high temperature strength, fatigue and corrosion resistance. Low cost, rapid fabrication of this component can be done by Additive Manufacturing (AM) process where parts are fabricated by successive melting of layers of metal powder rather than like a conventional process. By AM each layer is melted to the exact geometry defined by a 3D CAD model and the same part could be fabricated within hours. The Phase I results demonstrated that additive manufacturing of superalloy (equivalent to 740 and 282 alloy) have similar or better mechanical properties compared to their wrought version fabricated by traditional processes. Addition of ceramic particles to superalloy improved the yield and UTS at a cost of little loss in ductility. Superalloy (equivalent to 740 and 282 alloy) AM fabrication development and optimization follow-on activities in Phase II will continue to focus on DOE needed specific component development and will also examine the possibility of further enhancing the MMC’s mechanical thermal and corrosion resistant properties. If successful, the rapid fabrication of superalloy component developed by AM in this SBIR program will reduce the cost and enhance the life and performance of current advanced turbine components such as casing/shroud, header, rotor/ disc, blade, bolt, superheater tubing and thick sections. The composite powders developed in this program could be used for thermal sprayed or cold sprayed steam oxidation, corrosion resistant high tempererature coating for retrofitting existing fossil-fired power plant equipment and also applied as laser additives manufacturing for turbine engine/ blade repairing or refurbishing