Aircraft alloy

Hi folks,
A quick question for the guys in aerospace and materials science. A long ti me ago, I remember hearing about an aircraft alloy (I think it was aluminiu m based) which followed a hardness curve over about 40 years during normal use (i.e., at normal aircraft operating temperatures). This meant that it w as strongest after about 20 years, and then became weaker with age. Can any one tell me the name of this alloy?
Thanks!
Chris

Duralumin - Al-Cu alloy - hardens over days at room-temperature after being quenched from solution-treated (essentially annealed state) - but as far as I know that then stays permanent. There isn't really any driving-force even in geological time (for mountains to flow into the sea (!)) for the structure to coarsen and loose yield strength. As far as I know ??? Rich S

On 2/23/2020 7:45 AM, Christopher Tidy wrote:
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Airplanes can experience fatigue overtime, but its from vibration and flex. You really shouldn't barrel roll a jumbo jet. LOL.

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The Duralumins (Al-Cu alloys) have low very predictable fatigue crack growth rates - reason they are still used for the bidirectionally stressed underwing panels of aircraft wings (?).

Am Sonntag, 23. Februar 2020 20:37:44 UTC+1 schrieb Richard Smith:
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Thanks for the thoughts. I'm at a loss to remember what the alloy was. It's possible (now I think about it) that it was for an engine part with a normal operating temperature which was a long way above room temperature.
Chris

On 2/23/2020 1:37 PM, Richard Smith wrote:
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There's transparent aluminum. The alloy is strong enough to be used for water tanks for whales but extremely light weight. I'm not sure of the long term fatigue rate. It's pretty hard to get as each time I've tried it's on back order with no delivery date. It's probably because the alloy contains a fair amount of Unobtainium.
Steve

On Monday, February 24, 2020 at 1:10:02 PM UTC-5, googlemyass wrote:
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ong time ago, I remember hearing about an aircraft alloy (I think it was al uminium based) which followed a hardness curve over about 40 years during n ormal use (i.e., at normal aircraft operating temperatures). This meant tha t it was strongest after about 20 years, and then became weaker with age. C an anyone tell me the name of this alloy?
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It is only available to Starfleet Rear Admiral, or higher.

wrote:
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Scotty and the mouse. CLASSIC ST.

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I absolutely agree that you shouldn't. But, technically speaking, there is nothing wrong with that. The barrel roll is a 1 G maneuver, so in principle, every airplane can do it.
Tex Johnston became famous for barrel rolling the 707, which at the time was a very large aircraft.

https://www.youtube.com/watch?v
ªA7kPfC5Hk

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Oh, NOW you tell me...