Ni-BASED ALLOY UNIDIRECTIONAL SOLIDIFICATION MEMBER AND MANUFACTURING METHOD OF UNIDIRECTIONAL SOLIDIFICATION MEMBER

摘要

PROBLEM TO BE SOLVED: To provide a Ni-based alloy unidirectional solidification member achieving both of higher mechanical properties and lower cost compared to conventional ones, and a manufacturing method of the unidirectional solidification member.;SOLUTION: In the Ni-based alloy unidirectional solidification member, the Ni-based alloy contains no Re as a chemical composition, the unidirectional solidification member has a structure of a turbine rotor blade in which a dovetail part, a shank part and a blade part are connected, an oxide coating film is formed on a surface of an area of thickness of 20 mm or more from the dovetail part to the blade part, no intergranular fracture exists in an area where the oxide coating film is formed, and the unidirectional solidification member has mechanical properties such that creep rupture time becomes 220 hours or more when a creep test is conducted under a condition of temperature of 1,040°C and stress of 137 MPa.;SELECTED DRAWING: Figure 1;COPYRIGHT: (C)2018,JPO&INPIT