Pressure-induced suppression of TCP stabilization during non-equilibrium solidification of liquid tungsten

Abstract The formation of topologically close-packed (TCP) structures is often considered an intrinsic feature of non-equilibrium solidification in metallic liquids. Whether such TCP stabilization is universal or can be altered by external thermodynamic fields, however, remains unclear. Here, molecular dynamics simulations are employed to investigate the role of external pressure in the non-equilibrium solidification of liquid tungsten (W), as well as the irradiation-induced structural evolution and tensile mechanical response of the resulting solidified structures. Results shows that, under low pressure, TCP structures emerge and persist during rapid cooling, whereas increasing pressure markedly suppresses TCP stabilization at an early stage of solidification. Instead of developing a saturated TCP network, the system undergoes an alternative solidification pathway in which the body-centered cubic (BCC) phase becomes stabilized at higher temperatures. Structural analyses reveal that pressure does not simply shift the balance between competing motifs, but fundamentally modifies the solidification pathway by preempting TCP growth before its stabilization. These results demonstrate that TCP-mediated structural evolution is not an inevitable precursor of crystallization, but is strongly contingent on the presence of external thermodynamic fields, providing new insights into non-equilibrium phase selection in refractory metals.