About this Abstract |
Meeting |
2023 TMS Annual Meeting & Exhibition
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Symposium
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Fatigue in Materials: Fundamentals, Multiscale Characterizations and Computational Modeling
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Presentation Title |
On the Low Temperature Fatigue Crack Growth Behavior of AA7075-T651 in Ultra-high Vacuum Environments |
Author(s) |
Zachary D. Harris, Adam Thompson, James Burns |
On-Site Speaker (Planned) |
Zachary D. Harris |
Abstract Scope |
It is well-established that the fatigue crack growth behavior of aerospace aluminum alloys in high altitude applications is sensitive to both temperature and water vapor pressure. To isolate the role of temperature, fatigue crack growth experiments are performed on AA7075-T651 under ultra-high vacuum conditions (10-9 torr) at temperatures ranging from 23°C to -65°C. All da/dN–ΔK relationships exhibit the following behaviors: (1) the classical Paris regime where all temperatures exhibit similar behavior, (2) a deviation from the Paris regime to lower da/dN, which occurs at higher ΔK as the temperature decreases, and (3) a coalescence in the da/dN for all temperatures in the threshold region. Interestingly, the point of deviation from the Paris regime is found to correlate with a transition from a flat, transgranular fracture morphology to slip-band cracking (SBC) across all conditions. The likely mechanisms governing the observed behaviors are then discussed, focusing on the role of slip. |
Proceedings Inclusion? |
Planned: |
Keywords |
Aluminum, Environmental Effects, Mechanical Properties |