Journal
COMPUTATIONAL MATERIALS SCIENCE
Volume 155, Issue -, Pages 340-349Publisher
ELSEVIER SCIENCE BV
DOI: 10.1016/j.commatsci.2018.08.064
Keywords
Additive manufacturing; SEBM; CET; Nickel-base alloy; Microstructure control; Computational thermodynamics
Categories
Funding
- Air Force Research Laboratory (AFRL) [FA8650-15-C-5205]
- U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy, Advanced Manufacturing Office [DE-AC05-00OR22725]
- UT-Battelle, LLC [DE-AC05-00OR22725]
- U.S. Department of Energy
- Department of Energy
Ask authors/readers for more resources
Solidification conditions experienced during Selective-Electron Beam Melting (S-EBM) of Nickel-Base superalloys generally lead to epitaxial grain growth from previous layers, resulting in highly textured columnar grain structures, and consequently, highly anisotropic mechanical properties. However, in recent work, researchers have been able to produce equiaxed grain structures by changing the scan strategy to influence the solidification conditions, thereby obtaining isotropic properties. The competition between columnar and equiaxed grain formation is governed by both the local thermal conditions and alloy thermodynamics. The above examples demonstrate successful manipulation of the thermal conditions through changes in process parameters. However, there is no guarantee that process conditions that encourage the formation of equiaxed grains for a given alloy will coincide with the production of defect free material. The goal of this work is therefore to understand the influence of alloy composition on the columnar-to-equiaxed transition (CET) so that alloys may be designed such that grain structure control is accessible to a wider range of S-EBM process conditions. A CET model originally developed by Hunt and extended by Gaumann was used to relate processing conditions to resulting microstructure. A sensitivity analysis of the CET model was performed using the Element Effects Methods. The results lead to a comparison of the relative effects of various alloying additions on the CET, as well as an assessment of other model parameters, including, most significantly, the nucleation density of equiaxed grains.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available