Constant load amplitude and ΔK fatigue crack propagation (FCP) tests have been carried out to investigate FCP behavior of grain size transition zone in a dual microstructure turbine disc. The results show grain size exerts more significant influence in the time-dependent FCP regime, but the effect of grain size is relatively limited in the cycle-dependent FCP regime. Larger local plastic deformation zone is found in fine-grained region, which is believed to be the reason that causes more significant grain boundary oxidation along with contribution from more grain boundaries acting as short-circuit diffusion paths of oxide-forming elements, resulting in accelerated FCP.

 已经进行了恒定载荷振幅和ΔK 疲劳裂纹扩展 (FCP) 测试，以研究 双微结构涡轮盘中晶粒尺寸过渡区的 FCP 行为。结果表明，晶粒尺寸在时间依赖性 FCP 机制中发挥更显着的影响，但在周期依赖性 FCP 机制中，晶粒尺寸的影响相对有限。 在细晶区发现较大的局部塑性变形区， 这被认为是导致更显着的晶界氧化的原因以及更多的晶界作为氧化物形成元素的短路扩散路径的贡献，导致加速FCP。