| XIA Tiancheng,YANG Xiaofeng,SHAO Zhaoyu,SUN Kai,LI Xiao,WANG Ji,LIU Yixin,CHEN Hao.Effect of Ultrasonic Rolling Process on Surface Integrity and Fatigue Life of Nickel-based Single Crystal Superalloy DD6[J],53(1):182-191 |
| Effect of Ultrasonic Rolling Process on Surface Integrity and Fatigue Life of Nickel-based Single Crystal Superalloy DD6 |
| Received:January 02, 2023 Revised:April 15, 2023 |
| View Full Text View/Add Comment Download reader |
| DOI：10.16490/j.cnki.issn.1001-3660.2024.01.017 |
| KeyWord:ultrasonic rolling nickel-based single crystal superalloy process parameters surface integrity fracture characteristics fatigue life |
| Author | Institution |
| XIA Tiancheng |
East China University of Science and Technology, Shanghai , China |
| YANG Xiaofeng |
East China University of Science and Technology, Shanghai , China |
| SHAO Zhaoyu |
AECC Commercial Aircraft Engine Co., Ltd., Shanghai , China |
| SUN Kai |
AECC Commercial Aircraft Engine Co., Ltd., Shanghai , China |
| LI Xiao |
Huzhou University, Zhejiang Huzhou , China |
| WANG Ji |
East China University of Science and Technology, Shanghai , China |
| LIU Yixin |
East China University of Science and Technology, Shanghai , China |
| CHEN Hao |
East China University of Science and Technology, Shanghai , China |
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| Abstract: |
| Nickel-based single crystal superalloy is one of the important materials for manufacturing aero-engine turbine blades. Due to long-term service in high-temperature and high-pressure environment, turbine blades are prone to wear, fracture and other accidents, and their surface integrity needs to be improved to extendtheir service life. In this work, ultrasonic rolling process(USRP) was used to strengthen the surface of nickel-based single crystal superalloy DD6. The vibration frequency of the ultrasonic generator was 10 kHz, and the static force and dynamic force were combined tobe applied to the workpiece surface. The orthogonal test method was used to test the three factors and three levels of sample group. The effect of ultrasonic rolling parameters such as static pressure, feeding rate and processing times on the surface integrity of nickel-base single crystal superalloy was investigated by three-position topography, microhardness tester, XRD diffraction and MTS universal fatigue tester, the corrosion solution mixed with 10% perchloric acid and 90% absolute ethanol was used to thin several strengthened samples layer by layer, and the distribution of residual stress on the surface of the strengthened samples with depth was studied after the average value was taken. The fatigue test was carried out at 650 ℃ high temperature to explore the law of improving the fatigue life of samples with different crystal orientations by ultrasonic rolling strengthening technology under different stress levels. The experimental results and theoretical analysis showed that the ultrasonic rolling strengthening process could reduce the surface roughness of the material, improve the surface microhardness, introduce a certain depth of residual stress in the material, and have different effects on improving the fatigue life under different stress levels. After USRP treatment, the best surface gain effect could be obtained for materials with different crystal orientations:the surface hardness increased from 465HV to 679.2HV, and the surface roughness decreased from 0.703 μm to 0.253 μm. The surface introduced residual compressive stress of about 782 MPa, and the average thickness of residual stress layer was 400 μm. It was found that residual stress layer and hardness layer were related to plastic deformation layer formed after surface impact. The fatigue life changes of materials were as follows:the fatigue life decreased when load was applied at a higher stress level. When load was applied at a stress level of 742.4 MPa, the fatigue life was 1.3 times higher than that of unreinforced samples, and the fatigue life was 1.5 times higher when the stress level was 649.6 MPa. The ultrasonic rolling process strengthening can effectively reduce the surface roughness of DD6 material, improve the surface microhardness and introduce a certain effective thickness of residual stress layer on the surface. The fatigue fracture is mainly slip fracture along {110} plane, and the fatigue life of DD6 under high temperature can be obviously improved by ultrasonic rolling strengthening. When the stress is lower than 742.4 MPa, ultrasonic rolling strengthening can significantly improve the fatigue life of DD6 material at high temperature. |
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