采用数值模拟与实验结合的方法，研究Ni含量对Al-5.6Zn-2.5Mg-1.6Cu-xNi（x=0%，0.1%，0.3%，0.5%，质量分数，下同）合金热裂倾向的影响。用ProCAST软件对合金的热裂倾向进行模拟，并结合OM，SEM，XRD，室温拉伸，析出相，应力场，热裂指数（hot tearing indicator，HTI），有效应力等分析表征方法系统地研究Al-Zn-Mg-Cu系合金的热裂行为和力学性能。结果表明：当Ni含量小于0.5%时，HTI值随Ni含量的增加先增加后降低，当Ni含量为0.5%时，HTI值最低；约束棒下端的有效应力随Ni含量的增加也呈先增加后降低的变化趋势，当Ni含量为0.5%时，有效应力最低。与未添加Ni的合金相比，添加0.5%Ni的合金热裂敏感性明显降低，力学性能大幅度提升，抗拉强度提高了54.79%，屈服强度提高了48.49%，拉伸应变提高了461%。数值模拟结果与实验结果具有很好的一致性。

A combination of numerical simulation and experimental methods was used to study the influence of Ni content on the hot tearing tendency of Al-5.6Zn-2.5Mg-1.6Cu-xNi （x=0%，0.1%，0.3%，0.5%，mass fraction， the same below） alloys. The hot tearing tendency of the alloy is systematically simulated using the ProCAST software， combining with optical microscopy （OM），scanning electron microscopy （SEM），X-ray diffraction （XRD）， room temperature tensile tests， precipitation phase， stress field， hot tearing index （HTI），and effective stress analysis methods. The hot tearing behavior and mechanical properties of the Al-Zn-Mg-Cu series alloys are systematically studied. The results show that when the Ni content is less than 0.5%， the HTI value first increases and then decreases with the increase of Ni content， and when the Ni content is 0.5%， the HTI value is the lowest. The effective stress at the bottom of the constraint rod also indicates a trend of first increasing and then decreasing with the increase of Ni content， and when the Ni content is 0.5%， the effective stress is the lowest. Compared to the alloy without Ni addition， the alloy with 0.5%Ni addition shows a significant reduction in hot tearing sensitivity， a substantial improvement in mechanical properties， an increase of 54.79% in tensile strength， an increase of 48.49% in yield strength， and an increase of 461% in tensile strain. The numerical simulation results are in good agreement with the experimental results.