Flow stress model considering the transformation-induced plasticity effect and the inelastic strain recovery behavior

Abstract

On the basis of continuum mechanics and the Mori-Tanaka mean field theory, a micro-mechanical flow stress model that considered both the transformation-induced plasticity (TRIP) effect and the inelastic strain recovery behavior of TRIP multiphase steels was presented. The relation between the volume fraction of constituent phases and plastic strain was introduced to characterize the transformation-induced plasticity effect of TRIP steels. Loading-unloading-reloading uniaxial tension tests of TRIP600 steel were carried out and the strain recovery behavior after unloading was analyzed. From the experimental data, an empirical elastic modulus expression is extracted to characterize the inelastic strain recovery. A comparison of the predicted flow stress with the experimental data shows a good agreement. The mechanism of the transformation-induced plasticity effect and the inelastic recovery effect acting on the flow stress is also discussed in detail.

Keywords

flow stress / transformation-induced plasticity / inelastic strain / elastic modulus

References

[1] Tsuchida N., Tomota Y. A micromechanic modeling for transformation induced plasticity in steels. Mater. Sci. Eng. A, 2000, 285(1–2): 345.

[2] Sugimoto K.I., Usui N., Kobayashi M., et al. Effects of volume fraction and stability of retained austenite on ductility of TRIP-aided dual-phase steels. ISIJ Int., 1992, 32(12): 1311.

[3] Dan W.J., Li S.H., Zhang W.G., et al. The effect of strain-induced martensitic transformation on mechanical properties of TRIP steel. Mater, Des., 2008, 29, 604.

[4] Andersson A. Numerical and experimental evaluation of springback in advanced high strength steel. J. Mater. Eng. Perform., 2007, 16(3): 301.

[5] Cleveland R.M., Ghosh A.K. Inelastic effects on springback in metals. Int. J. Plast., 2002, 18, 769.

[6] Li X.C., Yang Y.Y., Wang Y.Z., et al. Effect of the material hardening mode on the springback simulation accuracy of V-free bending. J. Mater. Process. Technol., 2002, 123, 209.

[7] Luo L.M., Ghosh A.K. Elastic and inelastic recovery after plastic deformation of DQSK steel sheet. J. Eng.. Mater. Technol., 2003, 125, 237.

[8] Morestin F., Boivin M. On the necessity of taking into account the variation in the Young modulus with plastic strain in elastic-plastic software. Nucl. Eng. Des., 1996, 162, 107.

[9] Yoshida F., Uemori T., Fujiwara K. Elastic-plastic behavior of steel sheets under in-plane cyclic tension-compression at large strain. Int. J. Plast., 2002, 18, 633.

[10] Benito J.A., Manero J.M., Jorba J., et al. Change of Young’s modulus of cold-deformed pure iron in a tensile test. Metall. Mater. Trans. A, 2005, 36(12): 3317.

[11] Pérez R., Benito J.A., Prado J.M. Study of the inelastic response of TRIP steels after plastic deformation. ISIJ Int., 2005, 45(12): 1925.

[12] Eshelby J.D. The determination of the elastic field of an ellipsoidal inclusion and related problems. Proc. R. Soc. (London) A, 1957, 241, 376.

[13] Mori T., Tanaka K. Average stress in the matrix and average elastic energy of materials with misfitting inclusions. Acta Metall., 1973, 21, 571.

[14] Tomita Y., Okabayashi K. Tensile stress-strain analysis of cold worked metals and dual-phase steels. Metall. Trans. A, 1985, 16(5): 865.

[15] Streicher A.M., Speer J.G., Matlock D.K. Forming response of retained austenite in a C-Si-Mn high strength TRIP sheet steel. Steel Res., 2002, 73(6–7): 287.

[16] Yu H.Y., Gao Y.K., Meng D.J. Transformation behavior of retained austenite under different deformation modes for low alloyed TRIP-assisted steels. Mater. Sci. Eng. A, 2006, 441, 331.