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

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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)

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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

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• 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

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EN Division-Materials and MetrologyCERN/EN/MME-MM/NJ-EDMS1216580

Optical observations

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• 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

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• 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

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• 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

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• 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

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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

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• 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