The hot tearing behavior of the double ternary eutectic alloy system, Al-6Mg-xSi (0 to 6.0 wt pct Si) alloys, was evaluated by a constrained rod casting mold equipped with a thermocouple and a load cell connected to a data acquisition system. Experimental results were compared with the results calculated by Scheil’s model using Pandat software to predict the occurrence of hot tearing in Al-6Mg-xSi alloys. The curve of hot tearing susceptibility contained two peaks, which were mainly affected by the double ternary eutectic reactions and the solidification phases evolution. And it agreed with the Kou’s hot tearing index precisely. The types and fractions of solidification phases (Al₃Mg₂, Mg₂Si, and eutectic Si) determined by the addition of Si content changed the freezing range and eutectic liquid fraction greatly. In addition, the types, fractions, sizes, and distributions of solidification phases affected the nucleation, propagation, and healing of hot tear cracks. The maximum contraction force value decreased as the reduction of volume shrinkage coefficient due to the addition of Si content. The drop-in force value on the contraction force curve could indicate the occurrence of hot tearing, and predict the hot tearing susceptibility when considering the shrinkage coefficient.

双三元共晶合金系统Al-6Mg- x Si（0至6.0 wt pct Si）合金的热撕裂行为是通过装有热电偶和连接到数据采集系统的称重传感器的受约束杆铸造模具评估的。将实验结果与使用Pandat软件通过Scheil模型计算的结果进行比较，以预测Al-6Mg- x Si合金中热撕裂的发生。热撕裂敏感性曲线包含两个峰，主要受双三元共晶反应和凝固相演变的影响。它与寇氏的热泪指数恰好吻合。凝固相（Al ₃ Mg ₂，Mg ₂通过添加Si含量确定的Si和共晶Si）极大地改变了冻结范围和共晶液体分数。此外，凝固相的类型，分数，大小和分布会影响热撕裂裂纹的成核，扩散和修复。随着Si含量的增加，最大收缩力值随着体积收缩系数的减小而减小。收缩力曲线上的插入力值可以指示热撕裂的发生，并在考虑收缩系数时预测热撕裂的敏感性。