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Thermomechanical Processing of High T c Superconducting Wire. Super BSCCO Family C. Bjelkengren B. Cooper S. Maltas Y. King . Project Overview. B i S r C a C u O-2223 ceramic encased in a silver tape Supercurrent flows along Cu-O planes. Project Overview.
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Thermomechanical Processing of High Tc Superconducting Wire Super BSCCO Family C. Bjelkengren B. Cooper S. Maltas Y. King
Project Overview • BiSrCaCuO-2223 ceramic encased in a silver tape • Supercurrent flows along Cu-O planes Super BSCCO Family 2
Project Overview • Texture controls critical current Bad Good Worst Super BSCCO Family 3
As-received BSCCO-2223 Properties Volume % ~ 60 % BSCCO A cross section ~ 0.9 mm2 At Ni(l) T 4.14 mm Tc: 110 K Bc: 10-2 T Ic: 110 A 0.22 mm ST Super BSCCO Family 4
Cold Rolling Hot Rolling Uniaxial Deformation Compression Annealing Annealing Directional Grain Growth Hot Isostatic Pressing Available Thermomechanical Processes Super BSCCO Family 5
Cold Rolling Hot Rolling Uniaxial Deformation Compression Annealing Directional Grain Growth Hot Isostatic Pressing Available Thermomechanical Processes Super BSCCO Family 6
Pure Annealing Super BSCCO Family 7
Cold Rolling Gained Access to Automated Precision Roller in NucE Super BSCCO Family 8
Cold Rolling • Fixed • O2 Partial Pressure: 107 Pa • Anneal Temperature: 815oC • Variable • Strain: ∆w / w0 • Anneal Time Super BSCCO Family 9
Cold Rolling Super BSCCO Family 10
Compression Annealing • Simultaneous heat, strain, and oxidation Super BSCCO Family 11
Compression Annealing • Fixed • O2 Partial Pressure: 107 Pa • Torque: 10 N·m • Variable • Anneal Time • Anneal Temperature Super BSCCO Family 12
Compression Annealing Super BSCCO Family 13
Hot Isostatic Pressing • t ~ 40 hours • T ~ 400-500 oC • P ~ 70 MPa • Ag-based solder • Annealing to restore Ox Super BSCCO Family 14
Hot Isostatic Pressing Temperature Pressure = 70 MPa 500 C Time 40 hours Super BSCCO Family 15
Cold Rolling Hot Rolling Uniaxial Deformation Compression Annealing Annealing Directional Grain Growth Hot Isostatic Pressing Results so Far! Super BSCCO Family 16
Cold Rolling Hot Rolling Uniaxial Deformation Compression Annealing Directional Grain Growth Hot Isostatic Pressing Results so Far! Super BSCCO Family 17
Loss of Superconductivity Super BSCCO Family 18
Improvements in Superconductivity Super BSCCO Family 19
Ic After Hot Isostatic Pressing ? Super BSCCO Family 20
Further Assessment • Deduce: • Most effective process variables using the variable-squares outlined above • Relate: • Improvements in Ic to better texture • Investigate: • Lotgering Factor • SEM Super BSCCO Family 21
Gantt Chart Super BSCCO Family 22