Mg–2xY–xTM(Zn,Cu,Ni) alloys reinforced with LPSO have outstanding mechanical properties, but there is less research on Mg–2xY–xNi hot tearing sensitivity. Therefore, based on Clyne Davies Model and Newton Baseline Method, the hot tearing tendency of Mg–2xY–xNi alloys with x = 0.5, 1, 1.5, 2.0, 2.5 wt% was quantified, and the tendency was further verified by the tearing evaluation of “T” shaped castings. The results show that the hot tearing susceptibility (HTS) decreases with the increase in x. Especially when x ≥ 1.5 wt%, and the HTS of Mg–Y–Ni alloys is even lower than that of Mg–Y–Zn alloys. The analysis of solidification microstructure evolution reveals that with the increase in x, the grain refinement and equiaxed tendency of α-Mg increases, and the solid fraction increases when dendrites are coherent, and the feeding stage of residual liquid phase between dendrites is shortened, which is an important reason for the decrease in hot tearing tendency. The analysis of phase transformation shows that with the increase in x, the residual liquid phase between α grains increases, which has better feeding effect on solidification, while the precipitation amount of LPSO phase which has coherent relationship with α increases, and its bridging effect on inhibiting grain boundary cracking is enhanced, which is another reason for reducing the HTS.

用LPSO增强的Mg–2 x Y – x TM（Zn，Cu，Ni）合金具有出色的机械性能，但对Mg–2 x Y – x Ni热撕裂敏感性的研究较少。因此，基于克莱恩·戴维斯模型和牛顿基线法，对x  = 0.5、1、1.5、2.0、2.5 wt％的Mg–2 x Y – x Ni合金的热撕裂趋势进行了定量，并通过以下方法进一步验证了这种趋势。 “ T”形铸件的撕裂评估。结果表明，随着x的增加，热撕裂敏感性（HTS）降低。特别是当x ≥1.5 wt％，Mg-Y-Ni合金的HTS甚至低于Mg-Y-Zn合金的HTS。凝固组织演变分析表明，随着x的增加，枝晶相干时α- Mg晶粒细化和等轴晶化趋势增加，固相分数增加，枝晶间残留液相的进料阶段缩短，这是热撕裂倾向降低的重要原因。相变分析表明，随着x的增加，α晶粒间的残余液相增加，对凝固有较好的进料效果，而LPSO相的析出量与α密切相关。 另外，HTS降低的另一个原因是其增加，并且其在抑制晶界裂纹方面的桥接作用增强。