×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

7075-O Natural Aging Time @ Room Temp

7075-O Natural Aging Time @ Room Temp

7075-O Natural Aging Time @ Room Temp

(OP)
I can't find any information on the natural aging time of 7075-O aluminum. I've checked the AMS book "Aluminum and Aluminum Alloys" and they dance around the question:

"Most of the heat treatable alloys exhibit age hardening at room temperature after quenching. The rate and extent of such hardening varies from one alloy to another. Microstructural changes accompanying room temperature aging, except for long-time aging of 7XXX alloys, are undetectable because the hardening effect are attributable solely to the formation of zone structure within the solid solution."

"Alloy 7075 and other 7XXX series alloys continue to age harden indefinitely at room temperature; because of this instability, they are very seldom used in the W temper."

I've only been able to find information on tempered 7075.

Does anyone know how fast annealed 7075-O naturally age hardens at Room Temp?? (if at all?)

http://files.engineering.com/getfile.aspx?folder=6...

http://files.engineering.com/getfile.aspx?folder=b...

RE: 7075-O Natural Aging Time @ Room Temp

You age from the solution treated condition. If you have annealed material (condition O), there will be no ageing.

RE: 7075-O Natural Aging Time @ Room Temp

(OP)
Thank you Swall.

Do you by chance know if any mechanical properties change at all in 7075-O or is it completely stable in that condition?

Why is solution treated 7075-W use more often than 7075-O? O condition would be more ductile and easier to form am I correct?

RE: 7075-O Natural Aging Time @ Room Temp

As swall mentioned, the mechanical properties essentially do not change (they are stable) for 7075 in the O temper (annealed). I'm not sure that I would say that -W is used more often than -O, but one reason to use age hardening alloys like 7075 in the solution treated condition is to perform cold working operations like drawing, extrusion, etc. so that the subsequent aging process will produce maximum strength. This process of solution treat (and quench) + cold work + artificial aging is called the T9 temper, and usually improves ultimate tensile strength by about 20-100 MPa vs. T6 temper. And yes, the annealed temper has maximum formability, but the difference between -O and -W is not all that great as long as the forming is done within several hours of the solution treating operation.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources