Oxygen changes crack modes of Ni-based single crystal superalloy
Xueqiao Li, Yinong Liu, Yunsong Zhao, Yanhui Chen, Ang Li, Jianfei Zhang, Yadi Zhai, Zhipeng Li, Dongfeng Ma, Xiaochen Li, Qing Zhang, Xiaomeng Yang, Haibo Long, Shengcheng Mao, Ze Zhang, Xiaodong Han
Abstract
Oxygen-affected cracking commonly presents on thin Ni-based single crystal superalloy components serving in high temperature and oxidizing environments. This study uses a newly developed in-situ thermal-stress environmental transmission electron microscope to investigate the oxidation and fracture behaviors of Ni-based single crystal superalloy at 650°C under stress. The in-situ oxidation was found to change the tensile fracture mode from the close-packed {111} planes of plastic fracture to {001} planes adjacent to γ/γ′ interfaces of brittle fracture. The microanalysis also revealed that the γ′ cuboids, γ phase, and γ/γ interface exhibit different oxidation behavior, thus underscoring the thickness debit effect.