Zhang Qunli, Zhang Jie, Zhuang Yifan, Lu Jinzhong, Yao Jianhua
Institute of Laser Advanced Manufacturing, Zhejiang University of Technology, Hangzhou 310023, China.
Collaborative Innovation Center of High-end Laser Manufacturing Equipment, Zhejiang University of Technology, Hangzhou 310023, China.
Materials (Basel). 2020 May 4;13(9):2128. doi: 10.3390/ma13092128.
Hot corrosion is one of the crucial failure modes of Ni-based superalloy components operating at high temperatures, which inevitably affects the subsequent mechanical properties of the alloys. In this research, damaged Inconel 718 alloy components with a pre-made trapezoid groove are repaired using laser additive manufacturing technique, and the change mechanisms of the microstructure and tensile properties of the repaired Inconel 718 alloy due to the hot corrosion in the salt mixture of 87.5 wt.% NaSO + 5 wt.% NaCl + 7.5 wt.% NaNO at 650 °C for different durations are investigated. The results show that oxidation and Cr-depletion occur on the repaired components due to the hot corrosion, and the corrosion products are mainly composed of CrO, FeO, and NiS. The tensile strength and elongation of the as-repaired specimens are 736.6 MPa and 12.5%, respectively. After being hot corroded for 50 h, the tensile strength increases to 1022.9 MPa and elongation decreases to 1.7%. However, after being hot corroded for 150 h, both tensile strength and elongation of the repaired specimens drop to 955.8 MPa and 1.2%, respectively. The mechanical performance alteration is highly related to thermal effects instead of the molten salt attack.
热腐蚀是镍基高温合金部件在高温下运行时的关键失效模式之一，这不可避免地会影响合金随后的力学性能。在本研究中，采用激光增材制造技术修复了带有预制梯形凹槽的损坏因科镍合金718部件，并研究了在650℃下于87.5 wt.% NaSO + 5 wt.% NaCl + 7.5 wt.% NaNO的盐混合物中进行不同时长热腐蚀后，修复后的因科镍合金718的微观结构和拉伸性能的变化机制。结果表明，修复后的部件由于热腐蚀发生了氧化和Cr贫化，腐蚀产物主要由CrO、FeO和NiS组成。修复后试样的抗拉强度和伸长率分别为736.6 MPa和12.5%。在热腐蚀50小时后，抗拉强度增加到1022.9 MPa，伸长率降低到1.7%。然而，在热腐蚀150小时后，修复后试样的抗拉强度和伸长率分别降至955.8 MPa和1.2%。力学性能的改变与热效应高度相关，而非熔盐侵蚀。
