Tensile testing of C17410 sheet before and after bakeout

Jorge Guardia-Valenzuela (EN-MME-EDS)

HiColDEM meeting 07-Nov-2018

Description of the material

Copper-beryllium

Cu-Be C17410 sheet from CERN store.

Thickness 0.33 mm

2

Specimen preparation

3

4 sets of samples:

• AR-RD

• AR-TD

• B-RD

• B-TD

RD - Rolling direction

TD - Transversal direction

AR - As received

B - Baked (standard bake-out 250˚C 48 h.)

Specimens “cut” by chemical etching at CERN

(masking + acid immersion).

Contact Découpe chimique: Bertrand Mehl/Benilde

Martins B.107

Holes were drilled for hanging them in the furnace

(small vacuum furnace at B.112).

(Fritz Motschmann)

Tensile specimen (type 1, Table B.1, annex B of ISO 6892-1)

Transversal

Description of the test

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Tensile tests were carried out at room temperature with a UTS®

electromechanical testing machine equipped with a 200 kN load cell and a

MFA25 contact extensometer according to the ISO 6892-1 requirements.

Main parameters for the test are the following:

Lc: 66 mm

L0: 50 mm

Preload at 10 MPa at 1 MPa.s-1

Method A (strain rate control): 0.10 mm.s-1 (εLc 0.0015 s-1)

Tensile tests and reports done by M.Crouvizier EN-MME-MM

Final report:

https://edms.cern.ch/document/1806321/1

As-received specimens: EDMS 1753333

Results

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Specimen Rp0.2 (MPa) Rm (MPa) A (%) Young modulus (GPa)

AR-RD 634.9 ± 10.2 743.1 ± 8.3 15.6 ± 0.4 126.7 ± 2.8

AR-TD 566.1 ± 10.2 664.8 ± 2.5 21.1 ± 1.1 126.4 ± 7.8

B-RD 611.4 ± 4.2 722.0 ± 2.9 15.9 ± 0.4 129.6 ± 7.6

B-TD 582.6 ± 8.0 672.3 ± 2.6 21.8 ± 1.1 125.6 ± 8.0

Tensile tests results (average ± std deviation).

Rm, Rp0.2 and Elongation are in accordance with given values for this product (CERN stores material

datasheet). Measured Young modulus are a little bit lower than values given in literature [1] (138 GPa).

Baking seems to homogenize tensile properties by decreasing a little yield and tensile strength in rolling

direction and increasing them a little bit in transverse direction. For a same sampling direction, elongation

remain unchanged after baking.

Reference:

[1]. ASM specialty handbook copper and copper alloys, page 473. J.R. Davis 2001.

Effect of bake-outs in the mechanical

performance of CuBe pieces. Comparison between C17200 and C17510/C17410

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Study done in August 2014 (J.Guardia)

Bake-out process

Schematic of the bake-out cycle of the collimators, VACUUM ACCEPTANCE TESTS FOR LHC COLLIMATORS

The collimator’s body is baked during 48 hours at 250°C. In the collimator life, it

is supposed to have 80 cycles of bake-out, which is 3840h ≈ 4000h

Comparison of Stress Relaxation

100

9384

70

55

33

100

97

85

62

20

0

10

20

30

40

50

60

70

80

90

100

50 100 150 200 250 300 350

Rem

ain

ing

stre

ss (

%)

Temperature (⁰C)

Remaining stress after 4000h * 250⁰C value for C17200 (alloy 25) is extrapolated

C17510 (3) andC17410 (174)

C17200 (25)

Alloy C17510 (3) is better in terms of retaining elasticity at high temperatures than

alloy C17200 (25), because at the same temperature, C17200 releases more stress

(or it retains less elasticity) than C17510.

At low temperatures the difference between both alloys is negligible, but C17200 has

a better behaviour.

Reference: Guide for Copper-Beryllium (FR),

BRUSHWELLMAN Engineered Materials

EXAMPLE

1000h, 300°C 42%

Comparison of Ultimate Tensile Strength

0

200

400

600

800

1000

1200

1400

50 150 250 350 450 550

UTS

(M

Pa)

Temperature (⁰C)

Ultimate Tensile Strength (MPa) [1]

C17510(alloy 3)

C17200(alloy 25)

0

10

20

30

40

50

60

70

80

90

100

100 150 200 250 300 350 400 450 500 550

Re

lati

ve U

TS (

%)

Temperature (⁰C)

Relative UTS loss [1]

C17510 (alloy 3)

C17200 (alloy 25)

Despite the lower Ultimate tensile strength at room

temperature in the alloy C17510, his behaviour at high

temperatures is better because its UTS is maintained

up to higher temperature.

In C17200 the UTS starts

to decrease sharply at

250⁰C, on the other hand

in C17510 falls at a

temperature about 400⁰C.

References: [1] SmithMetal Copper Datasheets

[2] S. Calatroni, LRFF Working Group (3rd Meeting)

Yield strength 0.2% offset, MPa

C17510 (alloy 3) HT [1] 650-870

C17200 (alloy 25) ½ H (TD02) [2] 510-650

C17200 (alloy 25) ½ HT (TH02) [2] 1100-1340

AR-RD

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As-received specimens: EDMS 1753333

AR-TD

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AR-RD

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AR-TD

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