AL 7050-T7451

[etorrecillas]

Hi all,

I was interested in knowing AL7050-T7451 mechanical properties after being heated to 180°C and cooled again to room temperature.
At MMPDS, I found a curve (Fig. 3.7.4.2.1), showed below:

At 180°C (356°F), strength is reduced, so I should have care about hot operation, but there is no mention about what happens to mechanical properties after slow cool-down process and returning to room temperature. Is original strength regained? In which levels? As I am not a material engineer and have few aknowledgments in this area, can anyone help me please?

Best regards,

Eduardo Torrecillas

 

[CastMetal]

T7451 Treatment for AL7050 is 24hrs+ at 320°F. This step in the process is to artificially age the Aluminum. A longer time or cycling in this temperature range would have little effect on material properties. I do not have specific experience heat treating 7050 but would believe this to be the case. Attached is the US military handbook on heat treatment of various aluminum alloys.
It is good to be careful using aluminum at elevated temperatures, keep in mind the reduction in strength is only linear up to a certain temperature (varies with alloy) then falls off precipitously.

Comprehension is not understanding. Understanding is not wisdom. And it is wisdom that gives us the ability to apply what we know, to our real world situations

 

[metman]

I agree for the most part with CastMetal except for the fact that 180C = 356 F > 320 F aging temperature. This will tend to overage.

Because 180C is above the aging temperaure, I blieve you can expect the the strength to be reduced 10% after returning to room temperature if the Al is held at temp up to 1/2 hour. Longer time at temperature will derate the strength more but temperature is the more critical factor.

Look again at MMPDS. There might be a room temperature strength graph for overaged 7050. I know there a graph for 2024.

Design for RELIABILITY, manufacturability, and maintainability

 

[Kwan]

There is a great source of info for this in a book called: Aerospace Structural Metals Handbook published by Cindas/urdue university. You might be able to find it here (my work internet doesn't allow me to go there):
ntrs.nasa.gov/search.jsp?R=19990076131

I have a 1992 edition and for material code 3222 (this is 7050) page 22 shows test data for T7451 exposed to temps for given times.

Hope this helps.