Application of thermodynamics in designing of advanced automotive steels

Abstract

Advanced automotive steels were designed with alloy concept and thermodynamics. Several phases were taken for the designing of transformation induced plasticity(TRIP) steels in accordance with the practical metallurgy process. Al was firstly chosen to substitute Si for improving galvanizing property, afterwards P was proved to be another alternative of Si by thermodynamic calculation and kinetic estimation. Thermodynamic investigation in the third phase revealed the effective function of Al to increase carbon solubility in austenite as well as TRIP effect of steel. Stack fault energy was calculated, in combination with heat treatment and microstructure measurement, which led to a successful composition designing of twin induced plasticity (TWIP) steel.

Keywords

Thermodynamics / Phase diagram / Materials designing / Advanced steel

References

[1] Matsumumura O, Sakuma Y, Takechi A. Enhancement of elongation by retained austenite in intercritical annealed 0.4 C-1.5 Si-0.8 Mn steel. Trans. ISIJ, 1987, 27: 570.

[2] Li Lin, De Cooman BC, Wollants P. Effect of aluminum and silicon on transformation induced plasticity of the TRIP steel. J Mater Sci Technol, 2004, 20(2): 135-138.

[3] Li L, Liu R, Shi W et al (2009) Development of a new type TRIP steel with good weldability and galvanizing property. In: Proceedings of international symposium automobile steel, Dalian, China, 2009, pp 332–336

[4] Guttmann M, Mclean D. Johnson WC, Blakely JM. Grain boundary segregation in multicomponent systems. Interfacial segregation, 1979, Metals Park: ASM 261-348.

[5] Hillert M, Staffansson LI. Regular-solution model for stoichiometric phases and ionic melts. Acta Chem Scand, 1970, 24: 3618.

[6] Li L, Delaey L, Wollants P, et al. Thermodynamic analysis of the segregation of multicomponent steels. J Chim Phys, 1993, 90: 305-311.

[7] Li L, Delaey L, Wollants P, et al. Thermodynamic calculation of segregation in multicomponent steels. J Mater Sci Technol, 1996, 12(3): 238-240.

[8] Guttmann M, Dumoulin Ph, Wayman M. The thermodynamics of interactive co-segregation of phosphorus and alloying elements in iron and temper-brittle steels. Metall Trans, 1982, 13A: 1693-1711.

[9] Li L. Weng YQ, Dong H, Gan Y. Microstructure and property control of advanced high strength automotive steel. Metalluygical, 2010, Beijing: Industry Press 265

[10] Mclean D. Grain boundaries in metals, 1957, Oxford: Clarendon Press

[11] Sundman B, Jansson B, Andersson J. The thermo-calc databank system. Calphad, 1985, 9(2): 153-190.

[12] Li L, Huang SG, Wang L, et al. Thermodynamic re-assessment of the Fe-Al-C system based on the Fe-rich experimental data. Front Mater Sci China, 2009, 3(1): 33-37.

[13] Redlich O, Kister AT. Algebraic representation of thermodynamic properties and the classification of solutions. Ind Eng Chem, 1948, 40: 345-348.

[14] Sundman B, Ågren J. A regular solution model for phases with several components and sublattices, suitable for computer applications. J Phys Chem Solids, 1981, 42(4): 297-301.

[15] Kumar KCH, Raghavan V. a thermodynamic analysis of the Al-C-Fe system. J Phase Equilib, 1991, 12(3): 275-286.

[16] Gustafson P. A thermodynamic evaluation of the Fe-C system. Scand J Metall, 1985, 14: 259

[17] Matlock DK, Speer JG. Haldar A, Suwas S, Bhattacharjee D. Third generation of AHSS, microstructure design concepts. Microstructure and texture in steels, 2009, New York: Springer 185-205.

[18] Li L, Gao Y, Shi W et al (2011) Martensite transformation in high Mn steels. HMnS2011, Soeal, Korea, p A19

[19] Olson GB, Cohen M. A general mechanism of martensitic nucleation: Part II. FCC→ BCC and other martensitic transformations. Metall Trans A, 1976, 7A: 1905-1914.

[20] Allain S, Chateau JP, Bouaziz O, et al. Correlations between the calculated stacking fault energy and the plasticity mechanisms in Fe-Mn-C alloys. Mater Sci Eng A, 2004, 387–389: 158-162.

[21] Dumaya A, Chateau JP, Allain S, et al. Application of thermodynamics and kinetics in materials engineering. Mater Sci Eng A, 2008, 483–484: 184-187.

[22] Inden G. Determination of chemical and magnetic interchange and magnetic interchange energies in BCC alloys. Metallkde Z, 1977, 68: 529-534.

[23] Hillert M, Jarl M. A model for alloying in ferromagnetic metals. Calphad, 1978, 2: 227-238.

[24] Dinsdale AT. SGTE data for pure elements. Calphad, 1991, 15: 317-425.