J Mater Sci Technol ›› 2003, Vol. 19 ›› Issue (Supl.): 105-108.

• Research Articles • Previous Articles     Next Articles

Physical Simulation of Thermally Induced Martensite Formation from Retained Austenite in TRIP Steels

Lie ZHAO, Fred J. VERMOLEN, Jilt SIETSMA, Sybrand van der ZWAAG   

  • Received:1900-01-01 Revised:1900-01-01 Online:2003-12-28 Published:2009-10-10
  • Contact: Lie ZHAO

Abstract: The present work analyses the total free energy of the material during the martensitic transformation. A general expression for the martensite fraction as a function of temperature is derived, assuming that the nonchemical free energy is proportional to the volume of martensite. This expression indicates that the temperature-dependent martensite fraction can be predicted once the characteristic transformation temperatures and the relation between the chemical free energy and temperature of the martensite and austenite are known. An advantage of this development is that the proposed equation is valid for all types of relations between the chemical free energy and temperature. This simulation is successfully applied to the martensitic transformation upon further cooling of retained austenite in a low-alloyed TRIP steel, in which the relation between chemical free energy and temperature is quadratic and the fraction is determined from a thermo-magnetic measurement.

Key words: Thermodynamics, Martensitic transformation, Retained austenite, TRIP steels