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Characterization of DISCUP C3/30 ODS Copper from Luvata OY/ECKA Granules for 11T DS Dipole project
EN Division-Materials and MetrologyCERN/EN/MME-MM/NJ-EDMS1216580
1
Domaine / Field: LHC –11T DS Dipole Project
Date: 8-5-2012
N° EDMS EDMS Nr.: 1216580
Requérant / Customer: D. Smekens (TE/MSC)
Liste de distribution / Distribution list: M. Karppinen (TE/MSC) S. Sgobba (EN/MME)
Données expérimentales / Experimental data:Samples : 2 x 600 mm long samples
Optical microscope: Microscope Digital KEYENCE; Quantimet Leica Q600Hardness :Wolpert hardness machineTensile tests: UTS tensile test machineSEM observations: ZEISS SigmaDimensional metrology: Digital level TESA
Sample description and tests performed
View of the 2 shapes in the “as received” state
a
b
• Two extruded and drawn shapes of approximately 600 mm long made of DISCUP C3/30 from Luvata OY/ECKA Granules have been characterized through different techniques:
• Dimensional metrology• Optical and SEM observations• Hardness measurements• Tensile tests
• The term “as received” (AR) refers to the shape prior to any heat treatment and “heat treated” (HT) following a Nb3Sn reaction type heat treatment (665 °C 50h)
2
EN Division-Materials and MetrologyCERN/EN/MME-MM/NJ-EDMS1216580
Face R30.1
Face A5000 µm
Cross section in comparison with the plane provided (LHCMBHSP0023)
Macro observations
Presence of some stain on the surface in the “As received” state3
EN Division-Materials and MetrologyCERN/EN/MME-MM/NJ-EDMS1216580
Dimensional metrology
• One of the shapes was cut into two halves of 300 mm length (Half 1 and Half 2) and a dimensional metrology was carried out in two of their surfaces (Face A and Face R30.1) to check the straightness in the “as received” and “heat treated” states
• The curvature is slightly reduced after the heat treatment in all the samples but in “Half 2 Face A”
4
-25 25 75 125 175 225 275 325
-0.2-0.15
-0.1-0.05
00.05
0.10.15
0.2
Half 1 Face A
ARHT
Distance from the extremity /mm
Devi
ation
/m
m
-25 25 75 125 175 225 275 325
-0.6
-0.3
0
0.3
0.6
Half 1 Face R30.1
ARHT
Distance from the extremity /mm
Devi
ation
/m
m
-25 25 75 125 175 225 275 325
-0.2-0.15
-0.1-0.05
00.05
0.10.15
0.2
Half 2 Face A
ARHT
Distance from the extremity /mm
Devi
ation
/m
m
-25 25 75 125 175 225 275 325
-0.6
-0.3
0
0.3
0.6
Half 2 Face R30.1
ARHT
Distance from the extremity /mm
Devi
ation
/m
m
EN Division-Materials and MetrologyCERN/EN/MME-MM/NJ-EDMS1216580
Optical observations before etching
5
• There is not visible porosity in any of the temper statesEN Division-Materials and Metrology
CERN/EN/MME-MM/NJ-EDMS1216580
AR HT
Electrical conductivityTemper state
Electrical
conductivity /%IACS
AR 88.7±0.1
HT 90.7±0.1
• The electrical conductivity is slightly increased after heat treatment
HT
AR
Optical observations after etchingTransversalLongitudinal
6
EN Division-Materials and MetrologyCERN/EN/MME-MM/NJ-EDMS1216580
Optical observations
7
• For the longitudinal images (parallel to the extrusion direction) in the previous slide, we can state that the piece is ultra-fine grained and that shows a fibrous structure.
• In the transversal images (perpendicular to the extrusion direction), the grains are equiaxed
• The grain size is slightly increased after the heat treatment as visible in both longitudinal and transversal cross cuts
• In left image, relative to the HT specimen, we can observe some recrystallization near the center region of the cross-cut, parallel to the extrusion direction
• These large recrystallized grains are common in the annealing of the ODS coppers and are due to primary recrystallization.
EN Division-Materials and MetrologyCERN/EN/MME-MM/NJ-EDMS1216580
Measurements parallel to the extrusion direction Measures in cross section
HRB (HV)
Temper 1 2 3
AR 70.7±1.5 (137) 71.7±0.6 (139) 70.3±1.5 (137)
HT 59.7±0.6 (118) 61.7±0.6 (121) 62±1 (122)
Pure Cu(O) 45
HV5
Temper A B
AR 137.2±2.8 147.2±3.3
HT 124.3±5 125.8±6.3
1 32 A
B
Hardness measurements
8
• The hardness does not vary in the length direction and is depressed by the heat treatment as expected
• Before the heat treatment, the values of hardness in the thick part of the cross section (A) are lower than the thin part (B) close to the sharp edge, however, after the heat treatment they become similar (annealing phenomenon). EN Division-Materials and Metrology
CERN/EN/MME-MM/NJ-EDMS1216580
CW 60%
Tensile tests
9
• The heat treatment reduces the yield and tensile strength and increases ductility
• As expected, mechanical properties at cryogenic temperatures are improved including ductility
Yield Strength Ultimate Tensile Strength Elongation0
200
400
600
800
0
10
20
30
40
50
60
70
397 414
271
353
486
629
341
540
9.21
12.69
21.4 20
RT - AR
RT - HT
4.2 K - AR
4.2 K - RT
Str
eng
th /M
Pa
Elo
ng
atio
n x
100
EN Division-Materials and MetrologyCERN/EN/MME-MM/NJ-EDMS1216580
Elongation vs. Temperature
AR
HT
10
• A common behavior for pure copper is that the elongation decreases when the temperature increases finding a minimum of elongation at around 250° C
% of flat fracture
RT 4.2 K
AR 66% 0%
HT 33% 0%
As received Heat treated0
5
10
15
20
25
Elongation (%)
Room temperature4.2 K
11
Comparison of results with supplier’s dataand Glidcop (C15715)
• According to the values of oxide content, the most similar ODS copper is C15715
• The closest tensile properties are observed are for a CW55% C15715
ECKA Granules ASM
MME-MMmeasurement AR (includes +
CW15% by Luvata)
Reference (“fully cold worked” by
Ecka)
C15715(CW 55%)
Al oxide content (wt%) Not available 0.60 0.70
UTS (MPa) 414 360-400 427
Yield strength (MPa) 397 300-340 407
Elongation (%) 9.21 15-20 18
HRB 71 65-70 68
Electrical conductivity (%IACS) 88.7 88-91 92
EN Division-Materials and MetrologyCERN/EN/MME-MM/NJ-EDMS1216580
CW 99%
4KRT
Conclusions
12
• The dimensions of the shapes have to be improved. The cross section does not perfectly fit the planes and the straightness could be improved. This straightness in fact changes when the shape is heat treated and might lead to a problem of dimensional stability.
• The mechanical properties are comparable to the ones of CW 55% C15715
• Strength and ductility increase at cold• HT samples show a partial annealing
• No porosity was found• The heat treatment have several effects in the properties:
• Changes the curvature of drawn shapes• Increases the electrical conductivity• Increases the grain size and promote some local recrystallization • Homogenizes the hardness across the section
EN Division-Materials and MetrologyCERN/EN/MME-MM/NJ-EDMS1216580