中文摘要：

通过对两种不同Ru含量（0%和2%,质量分数）的新一代镍基单晶高温合金DD22铸态及热处理态组织定量表征与1100~1150℃持久性能测试,研究了Ru对相转变温度、（γ＋γ′）共晶组织、凝固偏析、合金元素相成分、合金元素分配比及持久性能的影响。结果表明：Ru降低了合金的固液相线、铸态共晶组织体积分数以及凝固偏析程度。合金热处理后,与无Ru合金相比,含Ru合金γ′尺寸更为细小,γ/γ′两相中对TCP相析出有重要影响的Re和Cr元素分配更加均匀。Ru通过降低γ′相尺寸,增加γ/γ′错配度,提高固溶强化效果,抑制持久加载过程中TCP相析出,显著提高DD22合金持久性能。

英文摘要：

The effects of Ru on the as-cast,heat-treated microstructures and stress rupture properties under 1100-1150 ℃ were investigated in new generation Ni-based single crystal superalloys DD22 with two levels of Ru（0%and 2%,mass fraction） additions.The results indicate that the addition of Ru results in the decrease of the solidus and liquidus temperatures,the volume fraction of（-γ ＋ γ＇）eutectic as well as solidification segregation.The size of-γ＇ phase and elemental partitioning ratio of Re and Cr which are important for the precipitation of TCP phase decreases after heat treatment with Ru addition.Ru addition decreases the size of y＇ phase,increases γ/γ＇ misfit and solution strengthening effect and inhibits the precipitation of TCP phase in the process of stress rupture loading,which finally improve the stress rupture properties of DD22 alloy significantly.