| About this Abstract |
| Meeting |
2023 TMS Annual Meeting & Exhibition
|
| Symposium
|
Advanced Characterization Techniques for Quantifying and Modeling Deformation
|
| Presentation Title |
Size Effect in Polycrystalline Nickel-Based Superalloys in The Presence of a Free-Surface: Identification of the Crystal Plasticity of Surface Grains Versus Core Grains |
| Author(s) |
Damien Texier, Vincent Velay, Antonio Castro-Moreno, Daniel Monceau, Eric Andrieu |
| On-Site Speaker (Planned) |
Damien Texier |
| Abstract Scope |
Surface effects on the mechanical response of polycrystalline materials are particularly important for miniaturized components due to their high surface-to-volume ratio. Different grain-size microstructures and metallurgical states of an Alloy 718 Ni-based superalloy were purposely produced to investigate the influence of these microstructural features on the polycrystalline-to-multicrystalline transition (PMT). Ultrathin tensile specimens were thinned down (thickness of 15 to 500 µm) then tested. The macroscopic tensile properties were found insensitive to the specimen thickness beyond a certain thickness. Below the PMT, the yield strength, ultimate tensile strength and work-hardening decrease with the specimen thickness. This loss in mechanical properties is mainly attributed to a significant decrease in dislocation density within surface grains compared to core grains due to dislocation escape at the free-surface. A mean-field homogenization crystal plasticity model using fraction of core grains and surface grains was implemented for the identification of the mechanical behavior of miniaturized specimens. |
| Proceedings Inclusion? |
Planned: |
| Keywords |
Characterization, Mechanical Properties, Modeling and Simulation |