Thermo‐Mechanical Coupling and Asymmetric Deformation Mechanisms in Differential Temperature Rolling of Dual‐Phase Mg‐Li Alloy Slabs: A Numerical Study

ABSTRACT Dual‐phase Mg‐Li alloys represent a promising class of lightweight structural materials owing to their super‐light characteristics and high specific strength. However, they frequently exhibit a strength–ductility imbalance and develop a strong basal texture during conventional rolling (CR). In this study, we pioneer the application of a novel and practical differential temperature rolling (DTR) for processing these alloy slabs. A thermo‐mechanical coupled numerical model, validated experimentally, is developed to systematically analyze and compare the evolution of macro‐physical fields under CR and DTR. The results demonstrate that DTR generates an asymmetric temperature field (top‐cool and bottom‐hot) via roller temperature differences and promotes near‐isothermal rolling conditions. Furthermore, this process induces dynamic velocity reversal and the formation of a cross‐shear zone (CSZ). DTR also produces asymmetric deformation behavior in the slab, leading to a more complex and dispersed stress state characterized by enhanced shear effects. This distinctive deformation behavior, coupled with the thermodynamic driving force present in the high‐temperature region, substantially reduces the Zener‐Hollomon parameter, thereby suggesting a high propensity for enhanced dynamic recrystallization (DRX). Our findings provide insights into the DTR‐induced mechanisms, revealing that the asymmetric temperature field induces an asymmetric flow stress distribution, which leads to differential interfacial friction and dynamic velocity reversal. These combined effects ultimately result in the formation of a CSZ, which introduces additional shear deformation. This mechanistic framework offers theoretical support for exploring strategies to improve the strength–ductility balance, weaken texture, and refine grains in dual‐phase Mg‐Li alloys. It also provides critical guidance for industrial rolling design.