| 李艳明，王全，刘明坤，刘欢，李青，韩振宇.JG4246A高温合金尾喷管密封片裂纹机理分析[J].航空发动机,2021,47(6):96-102 |
| JG4246A高温合金尾喷管密封片裂纹机理分析 |
| Study on the Crack Failure Mechanism of JG4246A Nozzle Sealing Plates |
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| DOI： |
| 中文关键词: 密封片 JG4246A高温合金 热疲劳裂纹 热模拟 再结晶 残余应力 尾喷管 航空发动机 |
| 英文关键词:sealing plates JG4246A superalloy thermal fatigue crack thermal simulation recrystallization residual stress nozzle aeroengine |
| 基金项目:航空动力基础研究项目资助 |
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| 中文摘要: |
| 针对由Ni3Al基JG4246A高温合金精铸的航空发动机尾喷管密封片在工作后出现的裂纹故障，通过开展密封片外观检
查、裂纹断口分析、组织检查、化学成分分析、组织和再结晶热模拟试验等，对裂纹的性质和产生机理进行了分析。结果表明：密封
片的裂纹性质为以热应力为主导致的疲劳裂纹，起源于密封片表面的再结晶层。密封片边缘局部温度超过材料允许使用温度，使
其表面产生再结晶，在热应力作用下再结晶逐渐开裂形成微裂纹；局部超温也引起基体组织转变，降低了基体本身的高温性能，并
促进裂纹逐渐向基体扩展，最终形成宏观裂纹。为避免类似故障再次发生，建议进一步优化密封片结构，改善温度场温度梯度，降
低工作温度；增加去应力退火工艺，以降低构件的残余应力。 |
| 英文摘要: |
| Aiming at the crack fault on the aeroengine nozzle sealing plates casted by Ni3Al-based JG4246A superalloy，crack mode
and failure mechanism were identified by the visual inspection of sealing plates，fracture analysis of cracks，metallographic examination，chemical composition analysis，the thermal simulation experiments about organization and recrystallization. The results show that the crack on the sealing plates was fatigue crack induced by thermal stress，originated from the recrystallization layer on the surface of the sealing plates. Local over-temperature lead to re-crystallization layer on the edge of the sealing plates，and recrystallization gradually formed microscopic cracks under thermal stress. At the same time，local over-temperature also caused the transformation of matrix structure，reduced the high-temperature properties of the matrix，promoted the crack to gradually expand to the matrix and finally formed a macroscopic crack. It is advised that the further optimization design of structure are aimed to improve the premature field gradient and reduce premature，and stress relief annealing process can effectively reduce the residual stress of the material. |
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