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.

Previously, only superficial experimental observations have indicated that β’-series precipitates with significant strengthening effect can be sheared by basal 〈a〉 dislocations in Mg-rare earth (RE) alloys, while the corresponding mechanisms remain unclear. To address this issue, a phase-field (PF) simulation is conducted for a representative case: the interaction of β’_s-Mg₇Sm and basal 〈a〉 dislocations in Mg-Sm alloys. As a critical input for PF model, γ-surface (i.e., generalized stacking fault energy surface) of β’_s is computed using a novel ab-initio based method, where a carefully constructed multi-term Fourier series as a bridge, allowing molecular dynamics (MD) simulations to provide rough topography information to significantly reduce cost of first-principles (FP) calculations. The obtained γ-surface reveals multiple stable and unstable stacking faults (SFs) that may form during β’_s shearing. PF results further demonstrate that these SFs emerge along diverse deformation pathways of β’_s, governed by thermo-kinetic correlation, and reflect varied shearing mechanisms, including spontaneous SF transitions from an unstable one to a stable one, spontaneous formations of dislocation loops, complex stacking fault (CSF) ribbons and 2/3 <1100>-type compact super-dislocations, and SF accelerated dislocation cutting. These findings provide a reference for future experimental comparisons. The proposed γ-surface computation method is applicable to other β’-series precipitates, encouraging similar PF simulations in other Mg-RE alloys, while the dominant role of thermo-kinetic correlation in activating specific shearing mechanisms offers deeper insight into the design of precipitation strengthening.