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-Ce02 and IBAD-Gd2Zr207 buffer layers. A 20-mum 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 ~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.