About this Abstract |
Meeting |
2022 TMS Annual Meeting & Exhibition
|
Symposium
|
Deformation and Damage Mechanisms of High Temperature Alloys
|
Presentation Title |
Ultra-high Temperature Deformation in a Single Crystal Superalloy: Mesoscale Process Simulation and Micro-mechanisms |
Author(s) |
Yuanbo T Tang, Neil D'Souza, Bryan Roebuck, Phani Karamched, Chinnapat Panwisawas, David M. Collins |
On-Site Speaker (Planned) |
David M. Collins |
Abstract Scope |
A mesoscale study of a single crystal nickel-base superalloy subjected to an industrially relevant process simulation, relevant to casting, investigates the interplay between microstructural development and micromechanics. Test samples were smaller than the periodicity of the cored solidification structure, permitting the study of subtle composition variations. Foremost, hardening rates, influenced by differing γ’ precipitate solvus temperatures, were heavily influenced. Observed post-mortem, γ’ precipitates possessed a butterfly morphology, resulting from concurrent octodendritic growth and N-type rafting. High resolution-electron backscatter diffraction revealed deformation patterning follows the γ/γ’ microstructure, with high dislocation densities at γ/γ’ interfaces. Examination of residual elastic stresses indicated the butterfly γ’ precipitate morphology had enhanced deformation heterogeneity, resulting in stress states within the γ channels that favour slip, and encourages further growth of γ’ protrusions. The combination of localised plasticity and residual stresses are considered critical in the formation of the recrystallisation defect in subsequent post-casting homogenisation heat treatments. |
Proceedings Inclusion? |
Planned: |
Keywords |
High-Temperature Materials, Mechanical Properties, Phase Transformations |