Effects of cyclic stress and temperature on oxidation damage of a nickel-based superalloy

MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING

卷:528

Article

Karabela, A.¹  Zhao, L. G.¹  Tong, J.¹  Simms, N. J.²  Nicholls, J. R.²  Hardy, M. C.³ 

[1] Univ Portsmouth, Dept Mech & Design Engn, Portsmouth PO1 3DJ, Hants, England

[2] Cranfield Univ, Sch Appl Sci, Cranfield MK43 0AL, Beds, England

[3] Rolls Royce PLC, Derby DE24 8BJ, England

关键词: Oxidation;    Cyclic stress;    Oxide scale;    Micro-void;    Nickel-based superalloy;   

DOI  :  10.1016/j.msea.2011.04.029

来源: Elsevier

【 摘 要 】

Oxidation damage, combined with fatigue, is a concern for nickel-based superalloys utilised as disc rotors in high pressure compressor and turbine of aero-engines. A study has been carried out for a nickel-based alloy RR1000, which includes cyclic experiments at selected temperatures (700-800 degrees C) and microscopy examination using focused ion beam (FIB). The results suggest that the major mechanism of oxidation damage consists of the formation of surface oxide scales and internal micro-voids and oxide particles beneath the oxide scales, which become more severe with the increase of temperature. Applying a cyclic stress does not change the nature of oxidation damage but tends to enhance the extent of oxidation damage for temperatures at 750 degrees C and 800 degrees C. The influence of cyclic stress on oxidation damage appears to be insignificant at 700 degrees C, indicating a combined effect of cyclic stress and temperature. Further energy-dispersive X-ray spectrometry (EDXS) analyses show the enrichment of Cr and Ti, together with lower Ni and Co levels, in the surface oxide scales, suggesting the formation of brittle Cr2O3, TiO2, NiO and Co3O4 oxides on the specimen surface. Penetration of oxygen into the material and associated internal oxidation, which leads to further material embrittlement and associated failure, are evidenced from both secondary ion imaging and EDXS analyses. (C) 2011 Elsevier B.V. All rights reserved.

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