The state-of-the-art blades and vanes that are employed in modern, high efficiency power generation combustion turbine engines rely on high quality materials such as single crystal alloys and precise control of the part's internal and external dimensions. Because of the large size of these parts, cost-effective manufacturing is being pursued by several routes. As an alternative to conventional practices, i.e. single piece castings, Westinghouse has studied the potential for applying precision assembly of multiple cast subcomponents to deliver precise, high quality and cost effective components. Our research, which coupled design innovation with improved casting of advanced single crystal materials and high quality transient liquid phase bonding, is described. Microstructural and mechanical properties were studied to demonstrate that transient liquid phase bonding can produce single crystal structures that are effectively equivalent to design spercified single crystal material. Subsequently, it was demonstrated that judicious incorporation of the bond planes in the component design can provide for the effective implementation of this approach in turbine component manufacturing. The feasibility of developing a cost-effective production process for large components for advanced power generation combustion turbines has therefore bneen demonstrated.
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