J. Phys. IV France 112 (2003) 355
Martensitic transformation in Fe-Mn-(Si, Ge, Sn) alloysG.E. Monastyrsky1, Yu.N. Koval2, G.S. Firstov3 and J. van Humbeeck3
1 National Technical University of Ukraine, 37 Peremogy Av., Kyiv 03056, Ukraine
2 lnstitute of Metal Physics of National Academy of Science of Ukraine, 36 Vemadsky Av., Kyiv 03142, Ukraine
3 K.U. Leuven-MTM, Kasteelpark Arenberg 44, 3001 Leuven (Heverlee), Belgium
Effect of Ge and Sn on the martensitic transformation and shape memory effect in Fe-Mn(22-26at.%)-Si alloys is investigated by the substitution of Si by Ge or Sn from 1.5% to 6at. %. It was found that addition of Ge causes the transformation to perform in several steps. Substitution of Sn makes this effect more superior. Resistometry, calorimetric and dilatometer measurements reveal that one of the transformation stages is close to second order. It is characterized by small values of the thermal hysteresis and heat effect. Shape memory effect measurements have shown that only one of the transformations has a distinct shear nature. At the same time the relief typical for martensitic transformation was observed by optical microscopy. The nature of both stages of transformation is discussed.
© EDP Sciences 2003