Relationship between Anisotropic Stress Rupture Properties at High Temperature and Microstructure of Selective Laser Melting Mar‐M247 Alloy

The anisotropy in stress rupture properties of additively manufactured superalloys at elevated temperatures poses a critical challenge for their reliable application in aerospace components. In this study, a nickel‐based superalloy (Mar‐M247) with axial direction perpendicular and/or parallel to the printing direction is prepared by the selective laser melting (SLM) technique. The alloys with different microstructures are obtained by adjusting the heat treatment parameters. Following an optimized heat treatment consisting of hot isostatic pressing (1180 °C/160 MPa/4 h), solution treatment (1260 °C/4 h), and double‐stage ageing (1080 °C/4 h, 870 °C/24 h), the vertical sample exhibits excellent tensile performance at 760 °C, achieving an ultimate tensile strength of 1103 MPa and a fracture elongation of 14.6%. Under stress rupture conditions (760 °C, 724 MPa), the rupture lives of the horizontal and vertical samples are 6.5 h and 104.3 h, respectively. The observed anisotropy in stress rupture life is primarily attributed to differences in grain size, carbide morphology, and γ′ phase characteristics. These results provide a basis for the reduction of stress rupture anisotropy of SLM Mar‐M247 alloy and play a positive role toward its promotion in engineering applications.