以第一代镍基单晶高温合金 DD416 及其叶片为研究对 象 ， 采用 ProCAST 铸造 模 拟 软 件 对 Zr 含量 为0.001%、0.003%、0.007%、0.012%(质量分数 ，下同)的单晶 叶片的疏松缺陷进行模拟 。 结果表明 ，疏松缺陷主要分布于叶片缘板处，并随 Zr 的增加其含量先降低后升高。 实验表明，当 Zr 含量为 0.007%时，DD416 单晶叶片疏松缺陷最低，实验结果与模拟结果趋势基本相同。 分析其原因，当 Zr 含量从 0.001%增加至 0.007%时，叶片一次枝晶间距的变化是疏松缺陷的主要影响因素。Zr 含量的增加使叶片凝固过程中溶质的扩散激活能增大，扩散系数减小，使叶片一次枝晶间距减小，最终导致疏松缺陷含量降低，实验结果中疏松含量从 10Zr 的 0.463%降低到 70Zr 的 0.064%。 当 Zr 含量从0.007%增加至 0.012%时，此时疏松缺陷的主要影响因素为 γ/γ′共晶组织含量和凝固区间，共晶组织含量进一步增加，合金的固相线降低，凝固区间增大，导致疏松缺陷增加，实验结果中疏松含量增加到 0.493%。

To simulate the microporosity defects of single-crystal blades with Zr contents of 0.001 wt.%, 0.003 wt.%, 0.007 wt.% and 0.012 wt.%, the first-generation nickel-based single crystal superalloy DD416 and its blades were used as the research objects. The simulation results reveal that the microporosity defects are distributed mainly at the blade edge plate and that their content decreases first but then increases with increasing Zr. The experimental results and simulation results show essentially the same trend, and the experiments reveal that when the Zr content is 0.007 wt.%, the porosity defects of the DD416 single-crystal blade are the lowest. An examination of the reasons for this phenomenon reveals that when the Zr content increases from 0.001 wt.% to 0.007 wt.%, the change in primary dendrite spacing is the main factor influencing the formation of microporosity defects. An increase in the Zr content leads to an increase in the diffusion activation energy of solutes during the solidification process of the blades and a decrease in the diffusion coefficient, thereby decreasing the primary dendrite spacing and ultimately lowering the content of microporosity defects. The porosity defect content in the experimental results decreases from 0.463% in 10Zr to 0.064% in 70Zr. However, when the Zr content increases from 0.007 wt.% to 0.012 wt.%, the main influencing factors for microporosity defects are the volume fraction of the γ/γ′ eutectic phase and the solidification range. The content of the eutectic structure further increases, the solidus temperature of the alloy decreases, and the solidification range expands, resulting in an increase in microporosity. The porosity content in the experimental results increased to 0.493%.