Additive manufacturing has enabled us to manufacture components with design freedom and thin-walled structures. Laser Based-Powder Bed Fusion (LB-PBF) is one of the techniques which has captured the interest of the Superalloy community due to the possibility of having complex light-weight geometries with dedicated cooling channels and improved functionality by using LB-PBF. However, the microstructures of thin-walled structures are different from the one in the bulk material due to the difference in nucleation and growth as well as heat dissipation and is highly affected by the thickness of the geometrical features as well as thermal gradient (or, in other words, orientation in the build volume). Such a differences were clearly shown in case of 316L [1] and similar tendency is reported in IN939 in this study. This paper presents dedicated microstructure characterization of LB-PBF fabricated IN939 samples of different wall thicknesses (0.5, 1, and 2 mm) before and after heat treatment. The effect of microstructure on tensile and fatigue properties is presented and relationship between the two is discussed. The results obtained from this study can serve as a guideline for design optimization and simulations of IN939 samples manufactured using LB-PBF.

References

[1] A. Leicht, C. Pauzon, M.Rashidi, U.Klement, L. Nyborg, E.Hryha Advances in Industrial and Manufacturing Engineering, 2021, 2, 100037