| MA Xian-feng,SHI Hui-ji.Effect of Surface Recrystallized Grains on the Fatigue Performance of Turbine Blade DZ4 Alloy[J],45(4):110-115 |
| Effect of Surface Recrystallized Grains on the Fatigue Performance of Turbine Blade DZ4 Alloy |
| Received:January 31, 2016 Revised:April 20, 2016 |
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| DOI：10.16490/j.cnki.issn.1001-3660.2016.04.019 |
| KeyWord:directionally solidified alloy recrystallization surface treatment turbine blade fatigue life grain size crystal plasticity |
| Author | Institution |
| MA Xian-feng |
Institut Franco-Chinois de l'Energie Nucl佴aire, Sun Yat-Sen University, Zhuhai , China |
| SHI Hui-ji |
School of Aerospace Engineering, Tsinghua University, Beijing , China |
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| Abstract: |
| Objective To understand the effect of recrystallization (RX) on the fatigue failure mechanism of turbine blade DZ4 alloy, so as to develop a method to improve the fatigue life. Methods The domestic turbine blade DZ4 alloy was used. DZ4 was shot peened under different pressures (0. 1, 0. 3, 0. 5 MPa), and heat treated at 1220 ℃ to generate surface recrystallization. The microstructure of surface recrystallization was characterized by scanning electronic microscope (SEM). Fatigue testing was conducted on the raw DZ4 and surface recrystallized DZ4 alloy. Results Under lower pressure (e. g. 0. 1 MPa), recrystallization occurred in form of discrete recrystallized grains, which remarkably reduced the fatigue life of DZ4. Under higher peening pressures (0. 3 MPa and 0. 5 MPa), fully recrystallized grains were observed and the recrystallized thickness increased with peening pressure. The fatigue life of RX-0. 5 MPa sample could be longer than that of raw DZ4 alloy. Conclusion Recrystallization did not necessarily reduce the fatigue life of DZ4 alloy. Under lower shot peening pressure (e. g. 0. 1 MPa) and heat treatment, the discrete RX was the most detrimental to fatigue life. Under higher shot peening pressure (e. g. 0. 5 MPa), the compact recrystallized layer with fine grain size was beneficial to the fatigue life of DZ4. Crystal plasticity model was helpful in understanding and predicting the influence of RX on fatigue property. |
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