Abstract The effect of trace B on the microstructure and creep properties under 1100 °C/130 MPa in three single crystal superalloys with various levels of B (0, 0.01 and 0.02 wt %) additions was investigated. Compared with the boron-free alloy, the creep rupture life decreased slightly for the alloy with 0.01 wt % B, but dropped obviously for the 0.02 wt% B contained alloy. The low B addition had a slight effect on the main element compositions of γ/γ′ by the high precision atom probe tomography (APT) analysis and no significant change of γ/γ′ misfit was observed. However, the contents of Re, Mo, Cr in γ phase were decreased with the high B addition, resulting in the decrease of γ/γ′ misfit and increase of the spacing of γ/γ′ interfacial dislocation networks. Meanwhile, the residual (γ+γ′) eutectics and borides with a large volume fraction obviously decreased the creep rupture properties in the high B addition alloy. This study is helpful for understanding the boron's role of strengthening mechanism in high temperature creep of Ni-base single crystal superalloys.

中文翻译：

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微量硼对含稀土单晶高温合金组织演变和高温蠕变性能的影响

摘要 研究了微量 B 对三种不同水平 B（0、0.01 和 0.02 wt%）添加量的单晶高温合金在 1100 °C/130 MPa 下微观结构和蠕变性能的影响。与无硼合金相比，含 0.01 wt% B 的合金蠕变断裂寿命略有下降，但含 0.02 wt% B 合金的蠕变断裂寿命明显下降。通过高精度原子探针断层扫描（APT）分析，低B添加对γ/γ'的主要元素组成有轻微影响，未观察到γ/γ'失配的显着变化。然而，随着B添加量的增加，γ相中Re、Mo、Cr的含量降低，导致γ/γ'错配减少，γ/γ'界面位错网络间距增加。同时，残余(γ+γ′)共晶和体积分数大的硼化物明显降低了高硼合金的蠕变断裂性能。本研究有助于理解硼在镍基单晶高温合金高温蠕变中的强化机制。