气膜孔倾角角度对单晶高温合金疲劳性能的影响

In order to study the effects of the slant angle of film hole on the fatigue properties of single crystal superalloy, high temperature fatigue tests were carried out on 14 hole flat specimens with designed angle of 30°, 45˚, 90˚, respectively, under the same stress level, and the fracture analysis was carried out on the failure specimens. Based on the theory of crystal plasticity, numerical calculation was carried out for the flat plate with different slant angles of film holes, and the local stress and damage evolution of the hole edge were analyzed. The results show that the slant angle of the holes has a significant effect on the fatigue performance, and the order of the fatigue life is 90°>30°>45°. The number of cracks on the holes with the slant angle of 45° is significantly more than the other two type specimens. The numerical simulation shows that the accumulated strain of each cycle of 90° hole is relatively small, followed by 30° slant angle specimen and 45° slant angle specimen. The ratchet strain accumulation rates of 45° slant angle specimen and 30° slant angle specimen, respectively, are significantly higher than that of straight hole. The damage of 30° slant angle specimen is close to that of straight hole, and the damage of 45° skew hole is the largest. The calculation results are consistent with the experimental results.