Orientation control of multiple single crystal blades using a novel high-throughput mold via seeding-grain selection technique

Abstract

As the increasing demand for high temperature performance of the Ni-based single crystal blades, the orientation consistency of the blades has become more and more important. In this work, a novel high-throughput mold capable of producing four single crystal blades with exactly the same orientation was proposed. The effects of the two important parameters as connector height and blade placement angle on single crystal growth were investigated by ProCAST simulation. The results showed that the 90° connector with a height of 50 mm could obtain the most appropriate temperature gradient for the production of single crystal blades, and when the blades were placed at 120° and 270°, the flattest liquid isotherm could be obtained. However, due to the difference in the distance of the nucleation points from the mold center and the direction where the thin edge of the blade platform faced, the blade placed at 120° had a larger platform area occupied by the stray grains. Therefore, the structure of this mold was determined by using a 90° connector and placing blades at 270°. At last, using this mold, four single crystal blades with the same three-dimensional orientation and no stray grains were successfully produced. These results fully demonstrated the feasibility of this novel mold and also provided ideas for using simulation methods to guide the design of the new mold structure.