Constitutive modeling of the mechanical behavior of high strength ferritic steels for static and dynamic applications
- 250 Downloads
A constitutive relation is presented in this paper to describe the plastic behavior of ferritic steel over a broad range of temperatures and strain rates. The thermo-mechanical behavior of high strength low alloy (HSLA-65) and DH-63 naval structural steels is considered in this study at strains over 40%. The temperatures and strain rates are considered in the range where dynamic strain aging is not effective. The concept of thermal activation analysis as well as the dislocation interaction mechanism is used in developing the flow model for both the isothermal and adiabatic viscoplastic deformation. The flow stresses of the two steels are very sensitive to temperature and strain rate, the yield stresses increase with decreasing temperatures and increasing strain rates. That is, the thermal flow stress is mainly captured by the yield stresses while the hardening stresses are totally pertained to the athermal component of the flow stress. The proposed constitutive model predicts results that compare very well with the measured ones at initial temperature range of 77 K to 1000 K and strain rates between 0.001 s−1 and 8500 s−1 for both steels.
KeywordsConstitutive relations Temperature and strain rate effect High strength ferritic steel (HSS) Plasticity/viscoplasticity
Unable to display preview. Download preview PDF.
- Hecker, S.S., Stout, M.G., Staudhammer, K.P., Smith, J.L.: Effects of strain state and strain rate on deformation induced transformation in 304 stainless steel. I. Magnetic measurements and mechanical behavior. Metall. Trans. A 13A, 619–626 (1982) Google Scholar
- Johnson, G.R., Cook, W.H.: A constitutive model and data for metals subjected to large strains, high strain rates and high temperatures. In: Proceedings of the Seventh International Symposium on Ballistic, pp. 541–547. The Hague, The Netherlands (1983) Google Scholar
- Klepaczko, J.R.: Modeling of structural evolution at medium and high strain rates, FCC and BCC metals. In: Constitutive Relations and Their Physical Basis, pp. 387–395 (1987) Google Scholar
- Kocks, U.F., Argon, A.S., Ashby, M.F.: Thermodynamics and kinetics of slip. Prog. Mater. Sci. 19 (1975) Google Scholar
- Krauss, G.: Microstructures, Processing, and Properties of Steel. ASM Handbook 1, pp. 126–139 (1990) Google Scholar
- Nemat-Nasser, S., Isaacs, J.: Direct measurement of isothermal flow stress of metals at elevated temperatures and high strain rates with application to Ta and Ta-W alloys. Acta Metall. 45, 907–919 (1997) Google Scholar
- Orowan, E.: Discussion in Symposium on Internal Stresses in Metals and Alloys, p. 451. Institute of Metals, London (1948) Google Scholar
- Taylor, G.I.: Plastic strain in metals. J. Inst. Met. 62, 307–324 (1938) Google Scholar