在不同条件（760℃/750 MPa、850℃/500 MPa、980℃/260 MPa、1 050℃/140 MPa）下对DD407单晶高温合金进行蠕变试验，观察了蠕变断口形貌以及蠕变断裂后的显微组织和位错，分析了蠕变断裂机制。结果表明：在760℃下，试验合金发生滑移剪切断裂，γ'强化相稍有变形，但未出现明显筏排化结构；蠕变位错主要分布在γ/γ'相界面处，仅有少量位错切入γ'相。在850℃下合金仍主要发生滑移剪切断裂，γ'相开始出现筏排化；在980℃和1 050℃下，合金发生韧性断裂，并且γ'相筏排化随蠕变温度升高而越发严重；在1 050℃/140 MPa条件下γ基体通道出现大量位错塞积，大量位错以长直的位错线形态切入γ'相。

Creep tests were carried out on DD407 single crystal superalloy under different conditions (760℃/750 MPa, 850℃/500 MPa, 980℃/260 MPa, 1 050℃/140 MPa). The creep fracture morphology and the microstructure and dislocations after creep fracture were observed. The mechanism of creep fracture was analyzed. The results show that at 760℃, the test alloy fractured in slip shear modes, and the strengthening phase γ' was slightly deformed, but no obvious rafting structures were found; creep dislocations were mainly distributed at the γ/γ' phase interface, and only a small number of dislocations entered the γ' phase. At 850℃, the alloy still mainly fractured in slip shear modes, and the γ' phase began to show rafting structures. At 980℃ and 1 050℃, the alloy had ductile fracture, and the rafting of the γ' phase became more serious with the creep temperature. Under the condition of 1 050℃/140 MPa, a large number of dislocations were packed in the γ matrix channel, and a large number of dislocations cut into the γ' phase in the form of long straight dislocation lines.