短时过热对DD6镍基单晶高温合金蠕变性能的影响

Investigation on Effect of Short-term Overheating on Creep Properties of Nickel-based Single-crystal Superalloy DD6

  • 摘要: 多引擎旋翼机在飞行过程中可能遇到因单发失效(OEI)而造成其余发动机工作功率激增的情况,由此带来的短时过热效应可能影响航空发动机涡轮叶片的服役性能,尤其是涡轮叶片材料的蠕变性能。本研究聚焦于短时过热效应对常见镍基单晶高温合金DD6蠕变性能的影响,通过含有OEI阶段的非等温蠕变试验对短时过热效应进行评估,并对合金经过OEI处理后的微观组织进行表征和分析。研究结果表明:OEI引入的短时过热会导致合金在OEI作用阶段内的应变突增,并改变其随后的蠕变进程。短时过热会导致DD6合金中的主要强化相γ'相的体积分数显著降低,且其降低幅度与γ'相是否筏化具有紧密的相关性。

     

    Abstract: A rotorcraft aircraft with multiple engines may encounter one engine inoperative (OEI) situation during flight, leading to a surge in the operating powers of the remaining aero-engines. This will cause the turbine blades to suffer short-term overheating, which may affect the service performance and creep life of the blade material. To understand the effect of short-term overheating on the creep property of the nickel-based single-crystal superalloy DD6, widely used in turbine blades, we conduct the non-isothermal creep test considering the OEI stage to study the influence of short-term overheating, and analyze the microstructure of the material after OEI treatment. The test results show that overheating will cause a sudden strain increase in the OEI term and change the subsequent creep process. The short-term overheating causes a significant decrease in the volume fraction of the γ' phase, and the decrease is closely related to whether the γ' phase becomes rafted.

     

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