|About this Abstract
||Materials Science & Technology 2019
||Additive Manufacturing of Metals: Microstructure and Material Properties of Nickel-based Alloys
||Effect of Post-printing Heat Treatment on the Microstructure, Hardness and Phase Formation in Laser Powder Bed Fusion Inconel 718 Cuboids
||Amir Mostafaei, Runbo Jiang, Joseph Pauza, Scott Santoro, Anthony D Rollett
|On-Site Speaker (Planned)
Alloy 718 cuboids have been fabricated by laser powder bed fusion (LPBF). Various heat treatments including simulated hot isostatic pressing (simulated-HIP) and double aging (DA) resulted in a microstructural transition at the build direction from heterogeneous columnar grains with inter-dendritic micro-segregation to homogenous recrystallized grains with carbide precipitates. The effect of different heat treatments on the microstructure and phase formation was studied by electron microscopy in conjunction with electron backscatter diffraction and X-ray diffraction. Hardness mapping was performed on cross-sections including perpendicular and along the build direction to better understand the hardness distribution. The simulated-HIP process followed by a double aging treatment gives a homogeneous microstructure with nearly isotropic hardness. Electron microscopy observations revealed that the inter-dendritic micro-segregated regions are replaced by fine carbide precipitates. The results show that a simple post heat treatment not only homogenizes microstructure, but also enhances mechanical strength as measured by hardness.
||Planned: At-meeting proceedings