Construction and application of a multi-field coupling model for evaluating the hot tearing susceptibility of magnesium alloys under rotating magnetic field

Herein, a comprehensive 3D hot tearing testing model that coupled with transient electromagnetic force, fluid flow, heat transfer and solidification was constructed to quantify the multi-physical field coupling effects during the solidification process of magnesium alloys under rotating magnetic field, which are difficult to measure in experiments. The Mg-4Zn-1.5Ca-0.3Zr alloy was selected as the research object. The accuracy of the model was verified through experiments and theoretical calculations, and the hot tearing mechanism and crack arresting mechanism of magnesium alloys under the action of rotating magnetic field were revealed. The results show that the improvement of the hot tearing resistance of the alloy and the alleviation of stress/strain concentration are the main inducing factors for the reduction of the hot tearing susceptibility of magnesium alloys under the action of rotating magnetic field. Meanwhile, the optimized feeding channel improved the feeding efficiency of magnesium alloys, thereby enhancing their crack arresting ability. In addition, the application of rotating magnetic field reduced the solidification strain of the casting. This work has important practical significance for optimizing the parameters of electromagnetic casting and realizing the production of high-quality magnesium alloy castings. It is expected to provide strong theoretical support and technical guidance for the actual production in related fields.