Transport characteristics of CVD-YBCO coated conductor under hoop stress

Transport characteristics of IBAD/CVD-YBa2Cu3O7 (YBCO) coated conductor were measured at 4.2 K under hoop stress. The conductor was fabricated by a multi-stage metal-organic chemical vapor deposition (CVD) method. The YBCO layer was deposited on Hastelloy substrate with PLD-CeO2 and IBAD-Gd2Zr2O7 buffer layers. A 20-mu m silver layer was sputtered as a protective and stabilizing layer. The hoop stress test coils were fabricated by winding the conductor on a 250-mm diameter stainless-steel bobbin by five turns. Two coils, denoted as coils A and B, were fabricated. The Hastelloy substrate located outside for coil A and inside for coil B. Both coils were tested in magnetic field at 4.2 K under hoop stresses. Coil A and B experienced 1028 and 777 MPa at 11 T, 4.2 K. The measured stress-strain curves provided that the Young's modulus of the conductor was 190 GPa. The tolerable stress of similar to 1000 MPa and the Young's modulus of 190 GPa are consistent with the values obtained by a tensile test. The hoop stress test results indicates that the YBCO coated conductor is promising for application under huge hoop stress.