Microstructurally-sensitive fatigue crack nucleation and subsequently short crack growth were observed at an edge-notch in a textured Zircaloy-4 sample with the c-axis aligned perpendicular to the viewing surface. To understand the competition between the main crack and the secondary crack nucleation at the edge-notch root, a combined experimental and computational investigation was conducted to analyse various micro-scale mechanical quantities, including local strain, local stress, GND density, and stored energy density. A computational crystal plasticity finite element simulation that incorporated grain morphology, crystallographic orientation, and loading conditions was found to have good agreement with experimental results from the three-point bend fatigue test. The results showed that both the main crack and secondary crack nucleation sites had the highest magnitudes of local stored energy density, indicating that this factor was both necessary and sufficient for crack nucleation.

在纹理化的 Zircloy-4 样品的边缘凹口处观察到微观结构敏感的疲劳裂纹形核和随后的短裂纹扩展，其中 c 轴垂直于观察表面。为了了解边缘切口根部主裂纹和次裂纹形核之间的竞争，进行了实验和计算相结合的研究，以分析各种微尺度力学量，包括局部应变、局部应力、GND 密度和存储能量密度。结合晶粒形态、晶体取向和加载条件的计算晶体塑性有限元模拟被发现与三点弯曲疲劳试验的实验结果非常一致。