激光标刻、电解标刻对GH4169疲劳性能的影响

对GH4169合金进行激光标刻和电解标刻处理,研究了两种标刻工艺后GH4169合金的高周疲劳性能及其断裂机理。结果表明,激光标刻、电解标刻后试样的抗拉强度下降幅度很小,几乎不影响合金的抗拉强度,与未标刻的GH4169合金疲劳寿命相比,激光标刻后合金疲劳寿命下降19.2%,电解标刻后疲劳寿命下降16.0%。从标刻截面处观察发现激光标刻后的形貌较为尖锐,电解标刻的陷坑形貌较为圆滑。通过观察裂纹源区形貌发现未标刻试样裂纹从合金表面处萌生,激光标刻试样缺口处产生了高应力集中,加快了裂纹的萌生速率。电解标刻位置存在呈灰暗色的化学蚀刻层,进而引起裂纹的萌生和扩展,综合比较下航空用电解标刻工艺所标刻的试样比激光标刻工艺疲劳性能更优。

Effects of laser marking and electrolytic marking on fatigue properties of GH4169

The high cycle fatigue properties and fracture mechanism of GH4169 alloy after laser marking and electrolytic marking were studied. The results show that the tensile strength of the specimen after laser marking and electrolytic marking decreases very little, which almost does not affect the tensile strength of the alloy. Compared with the fatigue life of the unmarked GH4169 alloy, the fatigue life of the alloy after laser marking decreases by 19.2%, and the fatigue life of the alloy after electrolytic marking decreases by 16.0%. It is observed from the marking section that the morphology after laser marking is sharp, and the crater morphology of electrolytic marking is smooth. By observing the morphology of the crack source area, it is found that the crack of the unmarked sample starts from the alloy surface, and the notch of the laser marked sample produces a high stress concentration, which accelerates the crack initiation rate. There is a dark gray chemical etching layer at the electrolytic marking position, which leads to the initiation and propagation of cracks. By comprehensive comparison, the fatigue performance of the samples marked by the aviation electrolytic marking process is better than that of the laser marking process.