To enhance the mechanical strength of REBCO tapes, a technique involving the creation of "heterogeneous structures" within the REBCO layer has been developed. This method entails drilling small holes in buffer layers and filling them with metal material, resulting in the formation of heterogeneous structures that effectively suppress crack propagation. What we are concerned about is the mechanism by which these heterogeneous structures affect the crack propagation subsequently impacting the mechanical performance. Therefore, by introducing the phase-field method (PFM) of fracture, we presented the propagation path of the initial crack under tension in the REBCO layer with heterogeneous structures. Additionally, we established a quantitative correlation between the fracture ratio (crack depth/tape width) and tensile strain to characterize the influence of heterogeneous structures on mechanical performance. Our findings indicated that the presence of heterogeneous structures markedly restricts crack propagation, leading to a substantial increase in the tensile strength of the REBCO tape. Furthermore, we delved into the impact of heterogeneous structure density on fracture behavior. The results revealed that higher densities of heterogeneous structures were more effective in suppressing crack propagation. Considering that the heterogeneous structure reduces the effective current-carrying area, consequently causing critical current degradation, we also explored fracture behavior under various distributions of these structures. Our results demonstrate the possibility of mitigating critical current degradation while concurrently enhancing mechanical strength by strategically adjusting the distribution of heterogeneous structures.

为了增强 REBCO 胶带的机械强度，开发了一种在 REBCO 层内创建“异质结构”的技术。该方法需要在缓冲层中钻小孔并用金属材料填充它们，从而形成异质结构，有效抑制裂纹扩展。我们关心的是这些异质结构影响裂纹扩展进而影响机械性能的机制。因此，通过引入断裂相场法（PFM），我们给出了异质结构REBCO层中拉力作用下初始裂纹的扩展路径。此外，我们建立了断裂比（裂纹深度/带宽度）和拉伸应变之间的定量相关性，以表征异质结构对机械性能的影响。我们的研究结果表明，异质结构的存在显着限制了裂纹扩展，从而导致 REBCO 胶带的拉伸强度大幅增加。此外，我们深入研究了异质结构密度对断裂行为的影响。结果表明，异质结构密度越高，抑制裂纹扩展越有效。考虑到异质结构减少了有效载流面积，从而导致临界电流衰减，我们还探讨了这些结构不同分布下的断裂行为。我们的结果证明了通过策略性调整异质结构的分布来减轻临界电流退化同时增强机械强度的可能性。