• Fischer, Franz Dieter
• Antretter, Thomas

Abstract

<p>Tensile tests performed on materials of equal chemical composition may show entirely controversial elastic plastic characteristics depending on the preceding heat treatment. In the particular case of low alloyed TRIP (transformation induced plasticity) steels manufacturers have managed to stabilize retained austenite at room temperature whose presence is commonly held responsible for a significantly wide range of plastic straining before ultimate failure. Such a material behavior is naturally desirable for deep drawing processes. The applied tensile load gives rise to mechanical driving forces eventually triggering the transformation of microregions of retained austenite into martensite. This phase change, in turn, entails misfit strains large enough to initiate plastic yield around these newly formed martensitic inclusions. The current work focuses on the numerical quantification of the amount of plastification. Finite element models of unit cells containing a number of quasi-randomly oriented austenitic inclusions are used to investigate the influence of the volume fraction of retained austenite in the virgin material on the total elongation at fracture of the specimen. A comparison between the tendencies obtained in the numerical analyses with experimental data reveal the importance of taking into account metallurgical issues in order to satisfactorily explain the TRIP phenomenon.</p>

Topics

• impedance spectroscopy
• polymer
• inclusion
• phase
• steel
• chemical composition
• plasticity
• drawing