Rate-Dependent Stress/Strain Curves for 7075-T651 AL

Hello all. For some time now I've been looking for a good source of rate-dependent stress/strain data for 7075-T651 Aluminum. Any useful
input would be very much appreciated.
Thanks.
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JD wrote:

useful
How long have you been looking? Where have you been looking? A few minutes in one of the right places (Engineering Index) turned up the following magazine articles with data for other tempers:
TENSILE TESTING OF MATERIALS AT HIGH RATES OF STRAIN. Nicholas, Theodore (US Air Force Wright Aeronaut Lab, Wright-Patterson AFB, Ohio) Source: Experimental Mechanics, v 21, n 5, May, 1981, p 177-185
Abstract: A tension version of the split Hopkinson bar or Kolsky apparatus is developed for conducting tests in tension at high rates of
strain up to 10**3 s** minus **1. A number of aluminum, titanium, and steel alloys tested in tension show increasing degrees of rate sensitivity above 10 to 10**2 s** minus **1. Tests on 6061-T651 and 7075-T6 aluminum show measurable strain-rate sensitivity in tension at the highest strain rates, although similar tests in compression in the literature show essentially no strain-rate sensitivity. Details of the apparatus and instrumentation and guidelines for its use are presented. (20 refs.)
Revised form for the Johnson-Cook strength model Rule, William K. (Univ of Alabama); Jones, S.E. Source: International Journal of Impact Engineering, v 21, n 8, Sep, 1998, p 609-624 Abstract: Strength models play a key role in the numerical simulation of impact events. A revised form of the Johnson-Cook strength model is proposed in this paper. The revised model treats the sudden strengthening that many ductile metals exhibit at strain rates greater than 10<sup>4</sup>/s. Strain rates of this magnitude are generally considered to be beyond the capability of the split-Hopkinson pressure bar and so such abrupt strengthening behavior is often not observed and reported. A method to economically estimate all eight coefficients of the revised strength model using quasi-static tension data and Taylor impact test data reduced with a modified version of the EPIC finite element code is also described. Revised strength model coefficients were determined for: 7075-T6 aluminum, OFHC copper, wrought iron, and a high-strength steel (Astralloy-V), A good fit to the quasi-static tension data and Taylor impact test results was obtained for these four different metals. The behavior of the revised strength model at high strain rates also compared favorably with independent predictions from an analytical model calibrated with the Taylor impact data. (16 refs.)
Strain rate effects on tensile deformation of 2024-O and 7075-O aluminum alloy sheet Dorward, R.C. (Kaiser Aluminum & Chemical Corp); Hasse, K.R. Source: Journal of Materials Engineering and Performance, v 4, n 2, Apr, 1995, p 216-220 Abstract: Coarse- and fine-grained 2024 and 7075 alloy sheets were tensile tested at strain rates ranging from 10<sup>-3</sup> to 10<sup>2</sup>/s. Ultimate tensile strengths decreased up to 10<sup>-1</sup>/s and increased at higher strain rates. Total elongations at failure showed the same behavior with uniform and localized components showing similar dependencies on strain rate. The initial ductility decrease at low strain rates is attributed to thermal gradients associated with a transition from isothermal to adiabatic conditions. At strain rates above 10<sup>-1</sup>/s, ductility increases as strain rate hardening effects become dominant. Although the fine-grained materials had higher elongations than their coarse-grained counterparts, both variants responded similarly to changes in strain rate. The only difference was a tendency for off-center failures in coarse-grained specimens tested at the slower strain rates. (14 refs.) (Author abstract)
Pittsburgh Pete
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