A criterion based on solidification microstructure was proposed to precisely predict the hot tearing behavior of cast alloys, which takes into account the effects of both mechanical and nonmechanical factors. This criterion focuses on the events occurring at the grain boundary, which are determined by the thermal contraction, solidification shrinkage, grain growing and liquid feeding. This criterion responds to a series of factors that affect hot tearing, such as alloy composition, mold design, casting process and microstructure. Its credibility has been validated by studying the hot tearing behavior of Mg-Ce alloys. In conformity with the experimental results, this criterion predicted decrease in the number of rods occurring hot tearing with increasing cerium content. A simplified criterion was derived and validated by Mg-Ce (equiaxed grain) and Mg-Al (columnar grain) alloy systems, which is suitable for the case where the eutectic liquid fraction is low and the liquid feeding can be ignored. In addition, a hot tearing index for equiaxed grains was proposed, that is,$|\mathrm{d}T/\mathrm{d}\left(f_s^{1/3}\right)|$near${\left(f_{\mathrm{s}}\right)}^{1/3}=1$, and its prediction results were consistent with the hot tearing susceptibility calculated from the experimental results.

提出了一种基于凝固组织的判据来精确预测铸造合金的热撕裂行为，该判据同时考虑了机械和非机械因素的影响。该标准侧重于发生在晶界的事件，这些事件由热收缩、凝固收缩、晶粒生长和液体补给决定。该标准响应一系列影响热撕裂的因素，如合金成分、模具设计、铸造工艺和微观结构。其可信度已通过研究 Mg-Ce 合金的热撕裂行为得到验证。与实验结果一致，该标准预测随着铈含量的增加，发生热撕裂的棒的数量减少。Mg-Ce（等轴晶）和Mg-Al（柱状晶）合金系统推导出并验证了简化准则，适用于共晶液体分数低且液体补料可以忽略的情况。此外，还提出了等轴晶粒的热撕裂指数，即$|\mathrm{d}吨/\mathrm{d}\left(F_{秒}^{1/3}\right)|$靠近${\left(F_{\mathrm{秒}}\right)}^{1/3}=1$，其预测结果与实验计算得到的热撕裂敏感性一致。