A new casting process, Counter-gravity Low-pressure Inert-atmosphere (CLI) casting, has been developed for the production of integral turbine wheels and closed-face nozzle components for small power-generation turbine engines, also known as micro-turbines. Benefits of this casting process include improved cleanliness, improved fill of thin walls, and lower cost. In order to validate the ability of the CLI cast components to meet product and property requirements for micro-turbine engine applications~ the components were characterized via X-ray radiography, metallography and mechanical testing. These were compared with components produced by conventional vacuum gravity casting. Comparisons between the two processes have also been made to compare the component quality, and production cost. In general, the mechanical properties of CLI cast IN713 LC and MAR-M247 alloy components compared favorably with conventional gravity castings. Additionally; a reduction in FPI indications has been documented, which should lead to lower rework and scrap costs. Overall, CLI casting has been demonstrated to offer advantages over conventional gravity casting for several applications and alloy types.
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