镍基单晶冷却叶片高温持久性的理论与试验研究

采用含有0~4排气膜孔的薄壁平板试样模拟镍基单晶冷却叶片,研究了气膜孔排布对镍基单晶冷却叶片高温持久性的影响,并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,对不同气膜孔排布的薄壁平板试件进行有限元分析。试验结果表明,在气膜孔数相同的情况下,随着气膜孔排数的逐渐增多,冷却叶片高温持久寿命不断降低,且下降趋势逐渐加剧。文中提出了基于有限元数据的高温持久寿命预测幂函数模型,在对应孔排布、应力、温度条件下,其相对误差均小于3%,有限元分析得到的应力场分布结果与试样的断口形貌相吻合。

Theory and experiment study on stress rupture propertiesof nickel-based single crystal cooling blades

Thin-walled plate specimens with 0～4 rows of film cooling holes were used to simulate the air-cooled turbine blades.The effect of holes distribution on the lifetime until the stress rupture of nickel-based single crystal cooling blades was studied.Based on the crystal plasticity theory,a creep numerical model for single crystal materials was established,which was implemented into the Abaqus user subroutine.Finite element analysis(FEA)was carried out for specimens with different distribution forms of cooling holes.Experimental results show that with the same number of holes on DD6 specimens,the more rows of the holes are,the shorter stress rupture lifetime specimens it has.Moreover,with the increase of rows number,the descending of creep properties gradually accelerates.Power function models based on FEA data were developed to predict the creep life of the samples with a certain amount of cooling holes under predetermined temperature and loading conditions.The fractional errors of the results are all within 3％.Stress distribution results obtained by FEA coincide with the fracture position and the shape of samples after experiments.