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采用气膜孔薄壁平板试样模拟冷却叶片,并与无气膜孔薄壁平板试样蠕变试验结果进行对比,研究了气膜孔对镍基单晶合金冷却叶片模拟试样高温持久断裂寿命的影响.试验结果表明:在950℃和377MPa条件下,无气膜孔薄壁平板试样的高温持久断裂寿命大约是气膜孔薄壁平板试样的2倍,扫描电镜(SEM)断口分析可以看出蠕变损伤首先发源于气膜孔周围并在气膜孔边缘开始起裂.基于晶体塑性理论建立单晶材料蠕变数值计算模型,将其编入Abaqus用户子程序中,对气膜孔和无气膜孔两种薄壁平板试样进行模拟分析.模拟结果显示在气膜孔周边存在应力集中和应力重分布,数值模拟分析结果与试样的断口表面形貌吻合.为便于工程应用,将高温持久断裂寿命与十二面体滑移系最大分切应力幅表达成指数关系,蠕变试验结果表明此式在该应力、温度条件下具有良好的精度.
In this paper, a thin-walled thin-walled gas film was used to simulate the cooling blade and compared with the creep test results of thin-walled plate without gas film hole. Life span.The results show that the long-term rupture life at high temperature of the thin film without holes is about twice that of the thin-walled film with gas-film holes at 950 ℃ and 377MPa, It can be seen from the analysis that creep damage originates at the periphery of the gas film pore and begins to crack at the edge of the film pore. Based on the crystal plasticity theory, a numerical calculation model of the creep of single crystal material is established and programmed into Abaqus user subroutine. The results show that there are stress concentration and stress redistribution in the vicinity of the film hole.The numerical simulation results are in good agreement with the fracture surface morphology of the sample Engineering application, exponential relationship between the long-term rupture life at high temperature and the maximum shear stress amplitude of the dodecahedron slip system, the creep test results show that this formula has good accuracy under the stress and temperature conditions.