Engineers from the Edison Welding Institute, Columbus, Ohio, presented a discussion at the ASM International MS&T 2019 conference, of a study in which they reduced crack susceptibility in additively manufactured parts made of Hastelloy X.
Laser powder bed fusion has been successfully used in the production of various nickel-base superalloys such as IN718 and IN625. However, for other nickel-base superalloys characterized by high crack susceptibility, such as Hastelloy X, the occurrence of cracks is difficult to prevent, even when a process parameter optimization is applied.
In this study, the crack problem was mitigated by controlling the chemical composition and powder size distribution. The powder in this study met the conventional cast Hastelloy X commercial composition limits. However, laser powder bed fusion parts often show directional anisotropy in performance and material properties. Therefore, consideration is needed to ensure that the parts will have the required performance along the necessary load paths, and that these properties are reproducible.
The present study presents insights into the development of a heat treatment procedure that removes residual stresses and achieves an isotropic microstructure for tensile properties at room temperature and elevated temperature.
Optimization of Heat Treatment Parameters for Additive Manufacturing Hastelloy X
Alber Sadek and Hyeyun Song, Edison Welding Institute (EWI), Columbus, Ohio
