The Effect of Strain Rate on the Cyclic Stress-Strain Response of Metals.
MIDWEST RESEARCH INST KANSAS CITY MO
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Monotonic and cyclic strain hardening parameters were measured for five alloys 7075-T6 aluminum 6061-T651 aluminum an alphabeta brass alloy 365 copper-1.9 beryllium alloy 172 and martensitic 4340E steel. Cyclic measurements were made under fully reversed strain control at constant strain rate by the incremental step test. A maximum strain range of plus or minus 0.015 and strain rates of 0.003, 0.03, 0.10 and 0.30sec were used. The cyclic softeninghardening behavior of the alloys was predictable on the basis of established empirical rules. The cyclic stress-strain coefficients K and exponents n were independent of strain rate and had the values 7075-T6 105Ksi, 0.06 6061-T651 60 Ksi, 0.06 brass 132 Ksi, 0.21 copper-beryllium 165 Ksi, 0.13 4340E steel 300 Ksi, 0.19. Adiabatic heating in high-strength materials appears to impose an upper limit 0.3sec on the strain rate at which isothermal cyclic strain hardening tests can be performed. Author
- Metallurgy and Metallography