Abstract
Theta-shaped specimens were additively manufactured out of Inconel 718 powders using an electron beam melting technique, as a model complex load bearing structure. Two different build strategies were employed; producing two sets of specimens. Microstructural and micro-mechanical characterizations were performed using electron back-scatter, synchrotron x-ray and in-situ neutron diffraction techniques. In particular, the cross-members of the specimens were the focus of the synchrotron x-ray and in-situ neutron diffraction measurements. The build strategies employed resulted in the formation of distinct microstructures and crystallographic textures, signifying the importance of build-parameter manipulation for microstructural optimization. Large strain anisotropy of the different lattice planes was observed during in-situ loading. Texture was concluded to have a distinct effect upon both the axial and transverse strain responses of the cross-members. In particular, the (200), (220) and (420) transverse lattice strains all showed unexpected overlapping trends in both builds. This was related to the strong {200} textures along the build/loading direction, providing agreement between the experimental and calculated results.
| Original language | English |
|---|---|
| Pages (from-to) | 161-175 |
| Number of pages | 15 |
| Journal | Acta Materialia |
| Volume | 108 |
| DOIs | |
| State | Published - Apr 15 2016 |
Funding
This research was sponsored by the Laboratory Directed Research and Development Program of Oak Ridge National Laboratory , managed by UT-Battelle, LLC, for the U. S. Department of Energy. Research at MDF was sponsored by the U.S. Department of Energy , Office of Energy Efficiency and Renewable Energy , Advanced Manufacturing Office , under contract DE-AC05-00OR22725 with UT-Battelle, LLC. The research at ORNL's Spallation Neutron Source was sponsored by the Scientific User Facilities Division, Office of Basic Energy Sciences, US Department of Energy. This research used resources of the Advanced Photon Source, a U.S. Department of Energy (DOE) Office of Science User Facility operated for the DOE Office of Science by Argonne National Laboratory under Contract No. DE-AC02-06CH11357. EC and TRW would like to thank Mr. Tom Geer for metallographic sample preparation. EC would also like to acknowledge Dr. Olaf J. Borkiewicz for his helps during the measurements at APS.
Keywords
- Additive manufacturing
- Lattice strains
- Neutron diffraction
- Nickel-based superalloys
- Texture