7075-T6 S-N Curves

[themaniac]

Hey all,

I'm looking for S-N curves for AL 7075-T6.

I've looked at MIL-HDBK-5 and unfortunately the Kt value does not go high enough for me (the highest is 5.0 and i'm in the region of 8.0).

Naturally i'd prefer any electronic resources but then again anything would be better than nothing at all.

Cheers

 

[israelkk]

MIL-HDBK-5J available at

http://assist.daps.dla.mil/quicksearch/

 

[TVP]

israelkk,

Did you see that the originator of this question already referenced MIL-HDBK-5? Even the latest "J" revision that you indicated still does not have any data for Kt > 5.

themaniac,

I doubt that any other references will have data for Kt > 5, but the ones to check would be the following:

Aerospace Structural Metals Handbook (ASMH), 1999 ed.
Structural Alloys Handbook, 1996 ed.
Damage Tolerant Design Handbook

https://engineering.purdue.edu/IIES/CINDAS/Pubs_html

Perhaps you can just extrapolate from the available MIL-HDBK-5 curves would the decrement in fatigue strength would be for Kt ~ 8. Best of luck.

 

[jagad5]

Since you are going from Kt=5 to Kt=8, it is reasonably safe to ratio the curves. The scatter will generally decrease in higher Kt data. I notice that there are several Kt fatigue curves. Plot the effect of Kt on life for a specific stress, or effect of Kt on peak stress for a specific life, to search for evidence of the material pattern.

Doug

 

[nvalencia]

themaniac,

In the ASM Handbook, Volume 19 "Fatigue and Fracture", you can find a S-N field for Al 7075-T6 whit very sharp notch Kt>12 (chapter "Selecting Aluminium Alloys to Resist Failure by Fracture Mechanics", p.786 '96 Ed.) is a small graph, but is the only reference i know.