| Abstract Scope |
The shift toward electric arc furnace steelmaking intensifies tramp element accumulation in recycled steels. During hot rolling, Cu-rich liquid penetrates austenite grain boundaries, causing surface hot shortness. While Sn and Sb exacerbate damage and As mitigates it, the underlying mechanisms remain unclear. This study develops 2NN MEAM interatomic potentials for Fe–Cu–X (X = Sn, Sb, As, Bi, Pb) ternary systems and performs molecular dynamics simulations of early-stage liquid metal penetration along Σ5(310) grain boundaries of fcc Fe at 1400 K. Three regimes emerge from the asymmetry between Fe–X and Cu–X mixing enthalpies: cooperative (Sn, Sb), where tramp elements lead Cu into boundaries; suppressed (Bi, Pb), where unfavorable Fe interactions exclude them from the interface; and decoupled (As), where liquid phase separation isolates Cu penetration. Based on binary mixing enthalpies, this framework prioritizes elements for industrial control, supporting tolerance design in sustainable steel recycling. |