Investigation on the Fretting Wear Behavior and Mechanisms of Alloy 690TT during the Transformation from Mixed Regime to Partial Slip Regime Induced by Elevated Temperature

Abstract

Fretting wear of Alloy 690TT can occur in the steam generator of a nuclear power plant, in which the interfacial conditions are changed as the temperature varies. In this study, the gradual transformation from the mixed fretting regime (MFR) to the partial slip regime (PSR) occurred with an increase in test temperature. Correspondingly, there was a competition in wear modes due to the formation of a nanostructured tribologically transformed structure (TTS), presence of delamination cracking, nucleation of fatigue cracks, and oxidation. Delamination within the TTS dominated first. As the area of TTS and the plastic deformation region was reduced, fatigue cracks began to initiate. Oxidation was accelerated by an increase in the test temperature, and that effect resulted in reduced wear volume of Alloy 690TT in the MFR.

Keywords:

• Fretting wear
• wear mechanisms
• cracks
• oxidation

Acknowledgement

The authors thank Xue Liang from Shanghai University for preparation of the TEM specimens.

Additional information

Funding

We thank Xue Liang from Shanghai university for assistance in TEM experiments. We are grateful for the financial supports of the National Key Research and Development Plan (2016YFF0203804), the Beijing Natural Science Foundation (2194081), the Project funded by China Postdoctoral Science Foundation (2018M641187) and the Fundamental Research Funds for the Central Universities (FRF-TP-18-047A1).