Alternatives to 5154 Aluminium Alloy

[spggodd]

Hi guys,

I'm working on an aerospace heat exchanger which is currently using 5154 Aluminium Alloy but we're getting significant creep issues.

Does anyone have any idea on alternative material suggestions?

The material will have to have good weldability and be able to withstand high temperature (approx 350 Deg) and temperature gradients. I'm sure there's a lot more information that I could provide, please advise me, but take the above for a start.

Thanks!

 

[TugboatEng]

Why specifically does the material have to be weldable? Can you design your heat exchanger so it doesn't require welding? That opens up a whole world of high silicon and AlFe alloys.

Otherwise, does anybody have access to this?

https://www.sciencedirect.com/science/article/abs/pii/S0167844298000640?via=ihub

 

[tbuelna]

Might take a look at 2219-T81. Just be sure to keep sustained tensile stress levels <50% of yield strength to prevent stress corrosion problems. Below are properties in the weld joint and weldability rating.

You didn't mention what temper your 5154 aluminum is, but I'll assume it's -H4. I suspect the problem is occurring around the weld joint HAZ, where the yield strength is reduced. If possible, consider locally increasing the section thicknesses around the weld joints to keep stress levels far enough below the yield strength at operating temps to prevent creep.

I also like TugboatEng's suggestion of modifying the design to eliminate welding. Adds cost, but allows use of higher strength alloys. And would definitely improve reliability, which is an important consideration for an aircraft application.

Hope that helps.

 

[gtaw]

You should probably consider the fact that whether you weld heat treatable or nonheat treatable aluminum alloy, the mechanical properties in the base metal adjacent to the weld will be degradated. Your design assumptions should be based on the "as welded condition".

Best regards - Al