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Crack Initiation in Ni-Based Single Crystal Superalloy under Low-Cycle Fatigue-Oxidation Conditions

Authors :
Pengfei Wang
Xinbao Zhao
Quanzhao Yue
Wanshun Xia
Qingqing Ding
Hongbin Bei
Yuefeng Gu
Ze Zhang
Source :
Metals, Vol 13, Iss 11, p 1878 (2023)
Publication Year :
2023
Publisher :
MDPI AG, 2023.

Abstract

The mechanism of oxidation-assisted initiation of surface cracks of a fourth-generation Ni-based single crystal superalloy was systematically investigated during low cycle fatigue at 900 °C and 980 °C. The results show that cracks initiate near the surface defects at 900 °C, while they initiate in the surface oxide layer at 980 °C. At 900 °C, the oxidation microcrack initiation in the thicker inner oxidation layer is difficult to connect with the surface oxidation crack, which is an essential reason for the crack growth rate being slower and not becoming the main crack. At 980 °C, microcracks form in the outer oxide layer and quickly connect with microcracks at the surface and inner/outer oxide layer interface, growing into long cracks that become channels for rapid oxygen transport. This accelerates the crack growth rate, and eventually the oxide crack becomes the main crack.

Details

Language :
English
ISSN :
20754701
Volume :
13
Issue :
11
Database :
Directory of Open Access Journals
Journal :
Metals
Publication Type :
Academic Journal
Accession number :
edsdoj.0bb9e23fef51412faf710fc3d701bfc5
Document Type :
article
Full Text :
https://doi.org/10.3390/met13111878