Direct evidence of hydrogen-assisted crack nucleation and propagation associated with the δ phase in the selective laser melted GH4169 superalloy was obtained. The analysis of hydrogen trapping sites using thermal desorption spectroscopy revealed that the δ phase exhibits strong hydrogen capture capability, with a hydrogen desorption activation energy of 35.45 ± 2.51 kJ/mol. In addition, spatially resolved hydrogen mapping conducted by scanning Kelvin probe force microscopy and hydrogen microprint technique provided further evidence for the δ phase as a deep hydrogen trapping site. The atomic-scale characterization sufficiently reveals the deformation mechanism of the δ phase induced by dislocation accumulation. Hydrogen-promoted dislocation slip localization facilitates the formation of microvoid defects in the δ phase, which is the main reason for the δ phase fracture, and induces intergranular and transgranular cracks.

获得了选择性激光熔化 GH4169 高温合金中与 δ 相相关的氢辅助裂纹形核和扩展的直接证据。利用热解吸光谱对氢捕获位点进行分析表明，δ相具有很强的氢捕获能力，氢解吸活化能为35.45±2.51 kJ/mol。此外，通过扫描开尔文探针力显微镜和氢微印刷技术进行的空间分辨氢图谱为δ相作为深层氢捕获位点提供了进一步的证据。原子尺度表征充分揭示了位错积累引起的δ相变形机制。氢促进的位错滑移局部化有利于δ相中微孔缺陷的形成，这是δ相断裂的主要原因，并诱发沿晶和穿晶裂纹。