Investigation of Delamination Mechanisms in IBAD-MOCVD REBCO Coated Conductors

In recent years, remarkable technical advances have been achieved in the development of Rare-earth-Ba-Cu-O (REBCO) based coated conductors for large-scale applications. For coil-based applications (e.g., motors, generators, magnets), in addition to high critical current density under applied field, the conductor also needs to maintain mechanical integrity when exposed to transverse tensile stresses typically found in impregnated coils. In this study, we present a detailed analysis of the microstructure of REBCO coated conductors delaminated by application of transverse tensile stresses, in an effort to gain insight into the underlying mechanisms of failure and the weak link in the multilayer conductor architecture. In addition, we perform statistical analysis of delaminated areas of multilayer coated conductors subjected to c-axis pull experiments. Results on optical image correlation of fractured surfaces, analysis of buffer layer defects, and analysis of variance of data scatter are presented.