Interface mobility in massive transformation

To date, date concerning the interface mobility (M(T)) are rarely experimentally available. On the basis of knowledge of the driving force, the interface mobility can be calculated from the interface velocities. By applying an analytical transformation model that assumes site saturation, interface-controlled linear growth, and an impingement mode that varies with the cooling rate, the austenite-ferrite phase transformation occurring in a substitutional binary Fe-3 at.% Mn alloy is described. On this basis, interface mobility data for this massive transformation were deduced via analysis of the driving force, with specific values of M = 6.3exp(−154700/(RT)) (m∙mol/Js) or 38.1exp(−165500/(RT)) (m∙mol/Js). Additionally, the interface migration rate data obtained through the calculation of isothermal transformations following the CCT-TTT conversion further substantiated the rationality of the aforementioned data. To the best of our knowledge, the approach introduced here is the first case in which effective mobility data can be directly deduced from experimental results in combination with a reasonable transformation model.