Theanalyst: Some of these might not have the degree of specificity stated in your query, but they might be worth a try.
(1) Metals data including stress-strain and S-N curves. Select "Metals Handbook, MIL-HDBK-5H" at
.
(2) Stainless steel stress-strain curves in App. A, p. 18, in
(0.50 MB).
(3) Metals database (?),
.
(4) Steel sheet metal stress-strain curves (but I don't recognize the alloy names) in App. II in
(2.3 MB). Huge download, most of which is NOT stress-strain curves.
(5) Polymer stress-strain curves,
.
To disable pop-up windows and decrease load time at above and other sites, I turn off javascript for certain (or all) URLs. I saw this tip explained at
.
(6) Mild steel (ASTM A36M) stress-strain curve, stress in units of MPa as a function of strain, with Boolean coefficients, where "<=" means "less than or equal to," and ">=" means "greater than or equal to."
sign(x) = if(x<0,-1,1).
sigma
A36(x) = 0 + (|x|<=0.00125)(200000x) + (|x|>0.00125)(|x|<0.011)(sign(x))(250) + (|x|>=0.011)(|x|<0.232)(sign(x))(196.858 + 5399*|x| - 54375x^2 + 256000*|x|^3 - 503000x^4).
(7) ASM,
Atlas of Stress-Strain Curves, 2 ed., 2002,
.