| About this Abstract |
| Meeting |
MS&T22: Materials Science & Technology
|
| Symposium
|
Resisting Degradation from the Environment: A Symposium Honoring Carolyn M. Hansson’s Research and Pioneering Experiences as a Woman in STEM
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| Presentation Title |
Quantifying the Environmentally Assisted Cracking Initiation and Short Crack Behavior in New Generation 7xxx Aluminium |
| Author(s) |
Tim Burnett, Ryan Euesden, Yasser Aboura, Al Garner, Thomas Jailnin, Zak Barrett, Christian Engel, Phil Prangnell |
| On-Site Speaker (Planned) |
Tim Burnett |
| Abstract Scope |
New generation (new-gen) 7xxx aluminium alloys offer benefits in improved toughness and corrosion resistance. However, they can be more susceptible to Environmentally Assisted Cracking (EAC) in humid air. Initiation of EAC cracks has several mechanistically distinct stages of incubation, development of pre-cursors, proto-crack formation and short crack growth. Understanding initiation whilst critical to the overall material performance has always been difficult to study due to its stochastic nature. In this work, a high-resolution optical scanning system was developed, capable of in-situ monitoring the surface of constant displacement (4-point bend) tests. This has allowed for the unambiguous detection of EAC initiation sites and the ability to monitor the growth behaviour of short cracks in relation to the local microstructure. Subsequent site-specific fractography, combined with high–resolution SEM-EDX, has revealed the nature of the preferred initiation sites. This has led us to re-define the meaning of KEAC threshold in these materials. |