Initial prototype
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Thermomechanical Processing of High T c Superconducting Wire Super BSCCO Family C. Bjelkengren B. Cooper S. Maltas Y. King
Transcript of Initial prototype
Thermomechanical Processing of
High Tc Superconducting Wire
Super BSCCO Family
C. BjelkengrenB. CooperS. MaltasY. King
Super BSCCO Family2
Project Overview
BiSrCaCuO-2223 ceramic
encased in a silver tape
Supercurrent flows along
Cu-O planes
Super BSCCO Family3
Project Overview
Texture controls critical current
Good
Bad
Worst
Super BSCCO Family4
As-received BSCCO-2223 Properties
ST
0.22 mm
4.14 mm
Volume % ~ 60 % BSCCO
Tc: 110 K
Bc: 10-2 T
Ic: 110 A
A cross section ~ 0.9 mm2
At Ni(l) T
Super BSCCO Family5
Available Thermomechanical Processes Cold Rolling
Hot Rolling
Uniaxial Deformation
Compression Annealing
Annealing
Directional Grain Growth
Hot Isostatic Pressing
Super BSCCO Family6
Available Thermomechanical Processes Cold Rolling
Hot Rolling
Uniaxial Deformation
Compression
Annealing
Directional Grain Growth
Hot Isostatic Pressing
Super BSCCO Family7
Temperature (oC)
Time (min)
700 800 850 900
40
60
80
Pure Annealing
Super BSCCO Family8
Cold Rolling
Gained Access to Automated Precision Roller in NucE
Super BSCCO Family9
FixedO2 Partial Pressure: 107 Pa
Anneal Temperature: 815oC
VariableStrain: ∆w / w0
Anneal Time
Cold Rolling
Super BSCCO Family10
Strain (∆w/wo)
Time (min)
0.1 0.2 0.3 0.4
40
60
80
Cold Rolling
Super BSCCO Family11
Compression Annealing
Simultaneous heat, strain, and oxidation
Super BSCCO Family12
FixedO2 Partial Pressure: 107 Pa
Torque: 10 N·m
VariableAnneal TimeAnneal Temperature
Compression Annealing
Super BSCCO Family13
Temperature (oC)
Time (min)
200 300 500 700
10
20
40
Compression Annealing
Super BSCCO Family14
Hot Isostatic Pressing
t ~ 40 hours
T ~ 400-500 oC
P ~ 70 MPa
Ag-based solder
Annealing to restore Ox
Super BSCCO Family15
Hot Isostatic PressingTemperature
Time
40 hours
Pressure = 70 MPa
500 C
Super BSCCO Family16
Results so Far!
Cold Rolling
Hot Rolling
Uniaxial Deformation
Compression Annealing
Annealing
Directional Grain Growth
Hot Isostatic Pressing
Super BSCCO Family17
Results so Far!
Cold Rolling
Hot Rolling
Uniaxial Deformation
Compression
Annealing
Directional Grain Growth
Hot Isostatic Pressing
Super BSCCO Family18
Loss of Superconductivity
0
5
10
15
20
25
0 50 100 150 200 250
Current (A)
Vo
ltag
e (m
V)
Cold Rolled 'Hot' Rolled As-received
Super BSCCO Family19
Improvements in Superconductivity
0
5
10
15
20
25
0 50 100 150 200 250
Current (A)
Vo
ltag
e (m
V)
Compression Annealed As-received Annealed1 Annealed2
Super BSCCO Family20
Ic After Hot Isostatic Pressing
0
10
20
30
0 50 100 150 200 250
Current (A)
Vo
ltag
e (
mV
)
?
Super BSCCO Family21
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 Family22
Gantt Chart
5 4 3 2 1
Pure Anneal (2 out of 8 done)
Cold Rolling (2 out of 8 done)
Compression Annealing (1 out of 8 done)
Hot Isostatic Pressing
Prepare Detailed Processing Recepie
