| JI Chun-yan,HUANG Lei,XU Jia-le,CAI Jie,ZHANG Teng,MENG Xian-kai,HUANG Shu,ZHOU Jian-zhong.High-temperature Oxidation Resistance of IN718-Hf Coating by Ultrasonic Vibration-assisted Laser Cladding[J],52(9):199-208 |
| High-temperature Oxidation Resistance of IN718-Hf Coating by Ultrasonic Vibration-assisted Laser Cladding |
| Received:August 31, 2022 Revised:January 21, 2023 |
| View Full Text View/Add Comment Download reader |
| DOI：10.16490/j.cnki.issn.1001-3660.2023.09.016 |
| KeyWord:laser technology ultrasonic vibration nickel-based superalloy Hf microstructure high-temperature oxidation |
| Author | Institution |
| JI Chun-yan |
School of Mechanical Engineering, Jiangsu University, Jiangsu Zhenjiang , China |
| HUANG Lei |
School of Mechanical Engineering, Jiangsu University, Jiangsu Zhenjiang , China |
| XU Jia-le |
School of Mechanical Engineering, Jiangsu University, Jiangsu Zhenjiang , China;School of Mechanical and Electrical Engineering, Changzhou College of Information Technology, Jiangsu Changzhou , China |
| CAI Jie |
School of Mechanical Engineering, Jiangsu University, Jiangsu Zhenjiang , China |
| ZHANG Teng |
School of Mechanical Engineering, Jiangsu University, Jiangsu Zhenjiang , China |
| MENG Xian-kai |
School of Mechanical Engineering, Jiangsu University, Jiangsu Zhenjiang , China |
| HUANG Shu |
School of Mechanical Engineering, Jiangsu University, Jiangsu Zhenjiang , China |
| ZHOU Jian-zhong |
School of Mechanical Engineering, Jiangsu University, Jiangsu Zhenjiang , China |
|
| Hits: |
| Download times: |
| Abstract: |
| To improve the high-temperature oxidation resistance, the doping of Reactive Element (RE) and physical field are used to treat the surface of IN718 alloy, since the aerospace field has higher requirements for its high-temperature oxidation resistance. In this experiment, the IN718-Hf coating was fabricated on IN718 alloy by ultrasonic vibration-assisted laser cladding. The microstructure evolution and oxidation behavior of multiple coatings at 800 ℃ for 100 h were investigated. The microstructure, morphologies of oxide film, elemental distribution, and phase composition were studied by scanning electron microscopy (SEM), electron probe microanalyzer (EPMA), and X-ray diffractometer (XRD). The results indicated that the scale thickness of the IN718-0.3wt.% Hf coating was the thinnest and the oxide film was the most uniform among the coatings with different Hf contents (0, 0.3wt.%, 0.6wt.%, 0.9wt.%). With higher Hf content, more HfO2 was generated in the oxide scale, resulting in higher scale thickness and slight scale peeling. The excessive formation of HfO2 particles allowed rapid inward transport of oxygen, leading to an increase in the thickness of the oxide film. The high chemical activity of Hf made it easy to react with other elements and form new compounds in the molten pool, thereby increasing the number of nucleating particles during solidification and refining the microstructure of the coatings. The application of ultrasonic vibration increased the degree of supercooling of the molten pool, and at the same time broke the coarse columnar dendrites in the molten pool to further achieve grain refinement. The grain refinement was conducive to the formation of a more dense and uniform oxide layer, thereby improving the high-temperature oxidation resistance of the IN718 cladding layer. The oxide layer had a double-layer structure. The outer layer was MnCr2O4, and the inner layer was Cr2O3. The doping of Hf element and the application of ultrasonic vibration promoted the preferential formation of MnCr2O4 spinel oxide and Cr2O3. During this oxidation process, Hf prevented the outward diffusion of cations, but it did not prevent anions from diffusing inward. As a result, the growth of the oxide film changed from the outward diffusion of Cr3+ to the inward diffusion of O2–, which decreased the oxide film growth rate. Ultrasonic vibration further refined the microstructure of the coatings and induced a more uniform distribution of elements. It also increased the grain boundary density of the coating surface. Increased grain boundary density led to faster diffusion of Cr3+ in the coatings. Consequently, a stable, continuous, and compact Cr2O3 oxide film was formed over a short time. At the same time, the oxide nodules formed on the surface of the oxide film were more uniform and finer. Compared with the IN718 coating, the oxidation weight gain (0.349 mg/cm2) and oxidation rate constant (1.21×10–3 mg2.cm–4.h–1) of the ultrasonic vibration-assisted IN718-Hf coating were reduced by 46% and 69% respectively. The doping of Hf element and the application of ultrasonic vibration promote grain refinement, improve the high-temperature oxidation resistance, and expand the application of the IN718 alloy in the aerospace field. |
| Close |
|
|
|