Atomistic interaction between silicon and manganese in pearlitic steel: Combined atom probe tomography and first-principle calculations

Abstract

Atom-probe tomography (APT) and first-principle calculations are employed to investigate the role of Si on the partitioning behavior of Mn in pearlitic steel. Mn is experimentally observed to partition preferentially to cementite, while Si prefers to bcc α-Fe by APT. The partitioning ratio of Mn in SWRS87BM steel (i.e., 8.17±1.57) is more pronounced than that in SWRS82B steel (i.e., 3.66±0.44), which is attributed to the higher content of Si in the former than in the latter. First-principle calculations illustrate that Si atoms, which strongly partition to bcc α-Fe phase, repulse Mn atoms into cementite phase and increase the Mn partitioning ratio.