Zhou You-He, Liu Cong, Shen Lei, Zhang Xingyi
Key Laboratory of Mechanics on Disaster and Environment in Western China attached to the Ministry of Education of China, Lanzhou University, Lanzhou, Gansu, PR China.
Department of Mechanics and Engineering Sciences, College of Civil Engineering and Mechanics, Lanzhou University, Lanzhou, Gansu, PR China.
Nat Commun. 2021 May 25;12(1):3110. doi: 10.1038/s41467-021-23487-0.
The second generation HTS wires have been used in many superconducting components of electrical engineering after they were fabricated. New challenge what we face to is how the damages occur in such wires with multi-layer structure under both mechanical and extreme environment, which also dominates their quality. In this work, a macroscale technique combined a real-time magneto-optical imaging with a cryogenic uniaxial-tensile loading system was established to investigate the damage behavior accompanied with magnetic flux evolution. Under a low speed of tensile strain, it was found that the local magnetic flux moves gradually to form intermittent multi-stack spindle penetrations, which corresponds to the cracks initiated from substrate and extend along both tape thickness and width directions, where the amorphous phases at the tip of cracks were also observed. The obtained results reveal the mechanism of damage formation and provide a potential orientation for improving mechanical quality of these wires.
第二代高温超导带材制成后已应用于许多电气工程超导部件中。我们面临的新挑战是，这种具有多层结构的带材在机械和极端环境下是如何产生损伤的，而这也决定了它们的质量。在这项工作中，建立了一种将实时磁光成像与低温单轴拉伸加载系统相结合的宏观技术，以研究伴随磁通量演化的损伤行为。在低拉伸应变速率下，发现局部磁通量逐渐移动，形成间歇性的多层纺锤状贯穿，这对应于从基底引发并沿带材厚度和宽度方向扩展的裂纹，同时还观察到裂纹尖端的非晶相。所得结果揭示了损伤形成的机制，并为提高这些带材的机械质量提供了潜在方向。
