喷丸压力对GH3535合金表面状态及疲劳性能的影响研究

Research on the effect of Shot Peening Pressure on the Surface State and Fatigue Properties of GH3535 Alloy

摘要:

分别采用0.3MPa、0.45MPa和0.6MPa喷丸压力对GH3535高温合金表面进行喷丸。利用扫描电子显微镜（SEM）观察合金表面形貌、强化层组织结构，通过金相显微镜（OM）、维氏硬度计、X射线应力分析仪分析表层晶粒度、表层显微硬度、表层残余应力分布及X射线衍射峰半高宽。在室温条件下进行高周疲劳实验，并通过扫描电子显微镜（SEM）观察分析断口形貌特征。结果表明:GH3535合金喷丸后表层形成了晶粒细化层、硬化层和残余压应力层。且合金表面产生的晶粒细化层厚度、硬化层厚度以及残余压应力层厚度均随着喷丸压力的增加而提高。喷丸压力在0.3MPa～0.6MPa范围内，疲劳寿命受喷丸压力的影响较为敏感，且疲劳寿命随着喷丸压力的增加而提高。当喷丸压力为0.6MPa时，喷丸产生的效果最优，疲劳寿命提高了471.1%。喷丸后GH3535合金疲劳寿命的提高得益于合金表面状态的改善。

Abstract:

The surface of GH3535 superalloy was shot peened with shot peening pressures of 0.3MPa, 0.45MPa and 0.6MPa respectively. The optical profiler and scanning electron microscope (SEM) were used to observe the surface profile morphology of the alloy and the structure of the strengthening layer. Through metallographic microscope (OM), Vickers hardness tester, X-ray stress analyzer, the surface grain size, surface microhardness, surface residual stress distribution and X-ray diffraction peak half-height width are analyzed. The high-cycle fatigue experiment was carried out at room temperature, and the morphological characteristics of the fracture were observed and analyzed by means of scanning electron microscope (SEM). The results show that the grain refinement layer, hardened layer and residual compressive stress layer are formed on the surface of GH3535 alloy after shot peening. And the thickness of the grain refinement layer, the thickness of the hardened layer and the thickness of the residual compressive stress layer produced on the surface of the alloy all increase with the increase of the shot peening pressure.The shot peening pressure is in the range of 0.3MPa to 0.6MPa, and the fatigue life is more sensitive to the impact of shot peening pressure, and the fatigue life increases with the increase of shot peening pressure.When the shot peening pressure is 0.6MPa, the effect of shot peening is the best, and the fatigue life is increased by 471.1%.The increase in fatigue life of GH3535 alloy after shot peening benefited from the improvement of the alloy surface condition.