Biaxial residual stress measured in aluminum plate before and after stress relief

M. B. Prime and M. R. Hill, "Residual Stress, Stress Relief, and Inhomogeneity in Aluminum Plate," Scripta Materialia, 46, pp. 77-82, 2002. preprint (pdf) . (LA-UR-01-4723)

Two Specimens:
3-inch (75 mm) thick rolled 7050 Aluminum, 6 inch by 6 inch (150 mm by 150 mm) blocks

Solution treated and stabilized (7050-T74)
Stress relieved (7050-T7451) by stretching 1.5% to 3% in rolling direction

Two cuts each specimen:

First cut to measure rolling direction (x) residual stresses.
Second cut on half of specimen to measure transverse (y) residual stresses.
Cuts made in 1 mm depth increments.
Strain at each depth measured on top face (gages shown in picture) and back face (not visible) of specimens.

Photo of
aluminum block after cutting

Strain data

The Results:

results
Before stress relief

results
After stress relief

Residual stresses reduced by about a factor of 10. No problems measuring the stresses, even the low stresses after stress relief. These results are similar to other measurements, see Aluminum, Vol III., Fabrication & Finishing, by ALCOA

NOTE: The raw data from this test and any other data I have can be made available for research purposes. Just email me.

For additions, comments, or suggestions, contact Mike Prime at prime@lanl.gov
Technical questions welcome. Notification of typos, errors, bad links, etc. appreciated
Last Updated: October 6, 2003