European School “Bulk metallic glasses” Torino, September ...momo.ch.unito.it/PDF/Vaillant.pdf · behaviour indicated the existence of net compressive residual stress. ¾ Ti content:

European School“Bulk metallic glasses”Torino, September 2006

Influence of Ti content and partial crystallization on mechanical properties of

a Zr-base bulk metallic glass

Materials Characterisation & Processing GroupMaterials Characterisation & Processing GroupWaterford Institute of TechnologyWaterford Institute of Technology

Marie-Laure Vaillant

Materials Characterisation & Processing Group Materials Characterisation & Processing Group –– Waterford Institute of TechnologyWaterford Institute of Technology

Materials

Zr62-xTixCu20Ni8Al10 with x = 2.5and x = 3.5

Rods of 3 mm diameter manufactured by copper mould casting in Dresden* in two different states:

As-cast Annealed

Study of the influence on mechanical properties of - Ti content

- Partial crystallisation

*U. Kühn et al. Acta Mat. In Press (2006)


DSC analysis

500 550 600 650 700 750 800 850

Nor

mal

ized

exo

ther

mic

hea

t flo

w, a

.u.

Temperature, K

Ti 3.5%

Ti 3.2%

Ti 2.9%

Ti 2.5%

TA


Annealed samples

XRD scans

20 30 40 50 60 70 80

(200

000)

(110

010)

(101

000)

(111

100)

(111

000)

(111

101)

(210

001)

(110

000)

Inte

nsity

, a.u

.

2Θ, Degrees

Ti 2.5%

Ti 2.9%

Ti 3.5%

Ti 3.2%

(100

000)

TEM

Size ofquasicrystals:

≈200 nm

≈50 nm

200 nm

200 nm


Compression tests - Parameters

Temperature: Room temperature

Strain rate: 4.4 × 10-4 s-1

Testpieces: h ≈ 5.6 mmØ ≈ 3 mm

Testpieces NOT machined


Compression tests

-200

0

200

400

600

800

1000

1200

1400

1600

1800

2000

-0,01 0 0,01 0,02 0,03 0,04 0,05 0,06

D1_K189D2_K188

Stre

ss [M

Pa]

Strain [-]

1891 MPa1728 MPa

As-castAnnealedBrittleness Plasticity

2.5 % Ti


-200

0

200

400

600

800

1000

1200

1400

1600

1800

2000

0 0,01 0,02 0,03 0,04 0,05 0,06

D1_K194D1_K195

Stre

ss [M

Pa]

Strain [-]

Compression tests

1918 MPa1655 MPa

As-castAnnealedBrittleness Plasticity

3.5 % Ti


Compression tests - Results

2.5% of TiAs-cast

Annealed

Yieldstrengthσy (MPa)

E(GPa)

σf(MPa)

Plasticstrainεpl (%)

Fracturestrainεf (%)

As-cast

Annealed

65.3 1580 1728 1.95 4.81

72.6 - 1891 - 2.93

3.5% of Ti64.8 1350 1655 2.12 4.96

72.2 - 1918 - 3.25


Fracture surface

AS-CAST samples (exhibited some plasticity)

43°

Comp. axis


Fracture surface

As-cast samples(exhibited some plasticity)

Smooth regionVein-like pattern

River-like pattern


Fracture surface

As-cast samples (exhibited some plasticity)


Fracture surface

Annealed samples(exhibited brittleness)

*Chang et al. Mat. Sci. Eng. A 396 (2005) 423-428

Quasicrystal:Vf = 48 %, sizeQC= 200 nm (2.5 at% Ti)Vf = 63 %, sizeQC= 50 nm (3.5 at% Ti)


Fracture surface

Annealed samples(exhibited brittleness)


Comparison with other materials

Young's Modulus (GPa)10 100 1000

Ela

stic

Lim

it (M

Pa)

1

10

100

1000

10000

Lead Antimony Alloy

Tungsten

Platinum Iridum Alloy

Lead Tin Alloy Solder

Cast Magnesium

Tin Antimony AlloyPlatinum, Commercial Purity

Cast Nickel Tungsten Alloy

Zr59.9Ti2.5Cu20Ni8Al10

La50Al25Cu25

La55Al35Cu10

Pd40Cu30Ni10P20

Zr55Al15Ni10Cu20 Ti50Be40Zr10Fe81.1C13.8Si5.1

Fe40Ni40P14B6

12% Nickel silver (cast)

70/30 Copper-nickel (cast)

Zinc Copper Alloy

Grey (Flake graphite) cast iron (BS grade 150)

Carbon steel, AISI 1117 (normalised)Wrought aluminium alloy (6061-T4)


Comparison with other BMG

Young's Modulus (GPa)20 50 100 200

Ela

stic

Lim

it (M

Pa)

200

500

1000

2000

5000

Zr59.9Ti2.5Cu20Ni8Al10

Zr41.25Ti13.75Cu12.5Ni10Be22.5

Ti50Be40Zr10

Ti50Ni20Cu25Sn5

Zr55Al15Ni10Cu20

Fe40Ni40P14B6

Fe81.1C13.8Si5.1

Pd64Ni16P20

Pt60P25Ni15Pd40Cu30Ni10P20

LM2

Mg69Y21Cu10

Mg90Ca2.5Ni7.5

La55Al35Cu10

La50Al25Cu25


ConclusionResidual stresses Testpieces not machinedWith the exception of the sample annealed at 480°C, the σ – εbehaviour indicated the existence of net compressive residual stress.

Ti content: no significant influence on mechanical properties, i.e. for 2.5 / 3.5 at.%.Comparing as-cast and annealed

As-cast Annealed

E (GPa)

Yield strength σy (MPa)σf (MPa)

Plastic strain εpl (%)

Fracture strain εf (%)

65 721450 -1700 1900

2 ≈04.9 3.1


Future work

Influence of size and volume fraction of quasicrystals on mechanical properties for this Zr-base BMG


Thanks for your attentionThanks for your attention


Compression tests

-0.01 0 0.01 0.02 0.03 0.04 0.05 0.06 0.07

Strain [-]

0

200

400

600

800

1000

1200

1400

1600

1800

2000

Stre

ss [M

Pa]

D1_K189D1_K195D1_K194D2_K188

As-castAnnealed

Ti 2.5%Ti 2.5%

Ti 3.5%Ti 3.5%


Volume fraction of quasicrystals

Volume fraction of quasicrystals

Ti content Before compression

Aftercompression

2.5 %

3.5 %

Estimate of quasicrystals volume fraction in the annealed samples from DSC analysis:

Documents

European School “Bulk metallic glasses” Torino, September ...momo.ch.unito.it/PDF/Vaillant.pdf · behaviour indicated the existence of net compressive residual stress. ¾ Ti content: