About this Abstract |
Meeting |
2022 TMS Annual Meeting & Exhibition
|
Symposium
|
Deformation and Damage Mechanisms of High Temperature Alloys
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Presentation Title |
Precipitate Free Zone Formation in an Alumina-forming Austenitic Stainless Steel and the Effect on Mechanical Properties |
Author(s) |
Andrew Peterson, Ian Baker |
On-Site Speaker (Planned) |
Ian Baker |
Abstract Scope |
Alumina-forming austenitic stainless steels (AFAs) are a class of iron-based alloys being studied for use in high temperature applications, many of which are strengthened by nano-sized L12-structured precipitates. However, a L12 precipitate free zone (PFZ) can form along grain boundaries (GBs) at long creep times, which will likely have a negative effect on the creep strength. In this study, the formation mechanism and growth of L12 PFZs during creep in the AFA Fe-20Cr-30Ni-2Nb-5Al were studied using electron microscopy and energy dispersive x-ray spectroscopy. The PFZ formation and growth is due to the dissolution of L12 precipitates because of depletion of nickel and aluminum near larger Laves phase and B2-structured precipitates covering the GBs. Micro-cracks observed in the PFZ at long creep times suggest that fracture initiates in the PFZ, ultimately compromising the creep strength of the alloy. This research was supported by National Science Foundation Grant DMR 1708091. |
Proceedings Inclusion? |
Planned: |
Keywords |
Characterization, High-Temperature Materials, Iron and Steel |