In this paper, the creep behaviors and deformation mechanisms of a 3 wt% Re-containing single crystal superalloy, are investigated under two tough conditions of 1120 °C/137 MPa and 850 °C/690 MPa. The detailed TEM observation on interfacial dislocation networks and superdislocations are analyzed to interpret the creep resistance. Results show that at 1120 °C/137 MPa, dislocation networks degrade into unstable structures and give rise to the universal shearing of superdislocations. At 850 °C/690 MPa, three mechanisms including superdislocation pairs, stacking faults, and bypassing loops jointly contribute to the plastic deformation. In addition, the comparison of superdislocations and creep performance of superalloys with different Re contents are concluded. In general, the deficiency of interfacial dislocation networks and γ′ phases in resisting dislocation climbing and shearing causes the poor creep performance, which could be improved by stabilizing interfacial dislocation networks with additional W contents. This paper guides the composition optimization of low-cost third-generation superalloys in the future.

本文研究了含 3 wt% Re 单晶高温合金在 1120 °C/137 MPa 和 850 °C/690 MPa 两种恶劣条件下的蠕变行为和变形机制。分析了对界面位错网络和超位错的详细 TEM 观察，以解释抗蠕变性。结果表明，在 1120 °C/137 MPa 时，位错网络退化为不稳定结构并引起超位错的普遍剪切。在 850 °C/690 MPa 时，超位错对、堆垛层错和旁路环三种机制共同促成了塑性变形。此外，还总结了不同Re含量高温合金的超位错和蠕变性能的比较。一般来说，界面位错网络和γ'相在抵抗位错攀爬和剪切方面的不足导致蠕变性能较差，可以通过添加W含量稳定界面位错网络来改善蠕变性能。本文指导未来低成本第三代高温合金的成分优化。