GH4169鎳基高溫合金的超高周疲勞性能

GH4169鎳基高溫合金的超高周疲勞性能Very High Cycle Fatigue Properties of GH4169 Ni-based Superalloy

在室溫下使用超聲疲勞試驗(yàn)機(jī)對GH4169鎳基高溫合金進(jìn)行了105~108周次的疲勞試驗(yàn), 獲得了S-N曲線并觀察了疲勞斷口形貌。結(jié)果表明: S-N曲線呈逐漸下降的趨勢, 沒有出現(xiàn)疲勞極限, 在超過107周次的循環(huán)后試樣仍發(fā)生疲勞破壞; 疲勞裂紋的萌生位置并未隨S-N曲線的下降呈現(xiàn)出規(guī)律性, 裂紋主要萌生于試樣表面, 少量萌生于試樣內(nèi)部; 在超聲疲勞載荷作用下試樣同時存在塑性和脆性兩種破壞方式。

The fatigue tests in 105-108 cycles of GH4169 Ni-based superalloy were carried out at ambient temperature by the ultrasonic fatigue tester, and then the S-N curve was obtained and the fatigue fracture morphology was observed. The results show that the S-N curve exhibited a descending trend and the fatigue limit was not observed. The fatigue fracture of the specimen still occurred when the number of cycles exceeded 107. The fatigue crack initiation positions didn′t show the regularity with the S-N curve descending. The fatigue cracks mostly initiated from the surface and few from internal of the specimen. Under the ultrasonic load the plastic and brittle failure modes were both found in the specimen.

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