On the basis of studying the effect of rare earth elements on hot tearing susceptibility (HTS) of Mg–Zn alloys, further exploring effective ways to reduce HTS of Mg–Zn–Y alloys are very important for the development and application of magnesium alloys. In this paper, the effects of 2 at% Y on HTS of MgZn₁ alloy and several grain refiners on HTS of MgZn₁Y₂ alloy were studied. The modified Clyne–Davies model is used to predict the HTS of the investigated alloys, which are found in the descending order: MgZn₁ > MgZn₁Y₂ > MgZn₁Y₂–0.5 wt% Na₂CO₃ > MgZn₁Y₂–0.5 wt% Ti > MgZn₁Y₂–0.5 wt% Zr. By means of XRD, SEM, TEM and EBSD, the evolution of the microstructure during solidification is revealed. The results show that the addition of 2 at% Y can not refine α-Mg grains, but it can change the precipitation type of the second phase. When the precipitation type of the second phase changes from Mg₇Zn₃ to Mg₁₂ZnY (LPSO phase) and Mg₃Zn₃Y₂ (W-phase), the solidification end temperature of the alloy increases by more than 100 °C, and the coherent lattice of LPSO and α-Mg has a better bridging effect on the grain boundary, which reduces the HTS by 28.4%. Moreover, the addition of 0.5 wt% Na₂CO₃, 0.5 wt% Ti or 0.5 wt% Zr is an effective method for α-Mg grain refinement, equiaxation and dendrite coherent delay of MgZn₁Y₂ alloy. In particular, the addition of 0.5 wt% Zr can reduce the α-Mg grain size of MgZn₁Y₂ alloy by 89.1% and increase the solid fraction by 45% when dendrites are coherent, which results in a 77.1% reduction in HTS.

在研究稀土元素对Mg-Zn合金热撕裂敏感性（HTS）的影响的基础上，进一步探索降低Mg-Zn-Y合金HTS的有效途径对镁合金的开发和应用非常重要。在本文中，2原子％Y上的MgZn的HTS的影响₁上的MgZn的HTS合金和几个晶粒细化剂₁ Ÿ ₂进行了研究合金。修正的Clyne-Davies模型用于预测所研究合金的高温超导，其降序顺序为：MgZn ₁  > MgZn ₁ Y ₂ > MgZn ₁ Y ₂ –0.5 wt％Na ₂ CO ₃ > MgZn ₁ Y_{2 –} 0.5 wt％的Ti> MgZn ₁ Y _{2 –} 0.5 wt％的Zr。通过XRD，SEM，TEM和EBSD，揭示了凝固过程中微观组织的演变。结果表明，添加2at％的Y不能细化α-Mg晶粒，但可以改变第二相的析出类型。当第二相的沉淀类型从Mg ₇ Zn ₃变为Mg ₁₂ ZnY（LPSO相）和Mg ₃ Zn ₃ Y _2时（W相），合金的凝固结束温度升高超过100°C，并且LPSO和α-Mg的相干晶格在晶界上具有更好的桥接效果，从而使HTS降低了28.4％。此外，添加0.5重量％的Na的₂ CO ₃，0.5重量％的Ti或0.5重量％的Zr为α-Mg的晶粒细化，equiaxation和的MgZn的枝晶相干延迟的有效方法₁ ý ₂合金。特别地，当树枝状晶体连贯时，添加0.5 wt％的Zr可以使MgZn ₁ Y ₂合金的α-Mg晶粒尺寸减小89.1％，并使固体分数增加45％，这导致HTS降低77.1％。