Abstract: As the main strengthening phase of austenite in Fe-15Mn-4.5Si-10Cr-5Ni shape memory alloy, the second phase particle Cr₂₃C₆ plays an important role in the shape memory properties. According to the classical grain boundary nucleation kinetics theory, the theoretical calculation of a series of related parameters including phase transition chemical free energy and interface energy of Cr₂₃C₆ and the selection principle of key parameters are analyzed and solved. This study proposes a relative quantitative theoretical method for calculating the precipitation of Cr₂₃C₆ in the austenitic matrix of Fe-15Mn-4.5Si-10Cr-5Ni shape memory alloys, that produces results consistent with experimental results. The calculated PTT curve (precipitation-temperature-time curve) can be used as a theoretical basis for the selection of aging treatment parameters of Fe-15Mn-4.5Si-10Cr-5Ni shape memory alloys.

Key words: shape memory alloys, Cr₂₃C₆, PTT curve, theoretical calculation