Magnetic Field-Assisted Twin-Roll Casting of AZ31 Magnesium Alloy: Multiphysics Regulation of Solidification Front and Edge Cracking Suppression

This study proposes a magnetic field assisted twin-roll casting strategy for AZ31 magnesium alloy plate, which actively controls the solidification shell morphology by optimizing the casting-rolling process parameters to reduce edge cracks in AZ31 magnesium alloy. Through multiparameter and multifield simulations, we demonstrate that under optimized process parameters – casting-rolling speed of 2–3 m/min, pouring temperature ≥ 680 °C, and heat transfer coefficient of 5000–6000 W/(m 2 K) – the magnetic field facilitates the transition of the solidification front from a concave (“O”) to a near-linear (“1”) morphology. This transformation is accompanied by a 62.5 % increase in the α-angle between the side seal plate and the solidification front, effectively suppressing edge cracking and improving strip quality. The work provides a mechanistic basis for the application of in-situ magnetic fields to achieve synchronized solidification and deformation in lightweight alloy strip casting.