J. Phys. IV France 01 (1991) C4-367-C4-372
THE COURSE OF THE VOLUME FRACTION OF MARTENSITE VS. TEMPERATURE FUNCTION Mx(T)B. SKROTZKI
Institut für Werkstoffe, Ruhr-Universität Bochum, Postfach 10 21 48, D-4630 Bochum 1, Germany
Next to the starting temperatures the course of the martensite formation is of special interest. It can be smooth, step-wise or burst-like. This depends on the alloy system, the defect structure including grain size of the austenite and on the morphology of the martensitic microstructure, i. e. on its nucleation and growth. Investigations on the transformation course of f.c.c. Fe-Ni-base, Fe-Mn and Fe-Cr-C alloys were compared with b.c.c. shape memory alloys. In burst-like transformation no continuous function volume fraction of martensite vs. temperature fα(T) can be observed. To describe some microstructures, fractal a analysis is applied, because conventional methods of quantitative metallography fail. With these investigations of the transformation course it is expected to get a better understanding of the martensitic transformation itself. Attemps are made for an analytical description of the fα(T)-function, based on experimental and theoretical analysis.
© EDP Sciences 1991