Development of high toughness Bulk metallic glass composite ...ocw.snu.ac.kr/sites/default/files/NOTE/10046.pdfDevelopment of high toughness Bulk metallic glass composite with Transformation
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Development of high toughness
Bulk metallic glass composite
with Transformation mediated 2nd phase
e-mail : hyunseok07@snu.ac.kr
2014.03.25. Current Status of Structural Materials
Seoul National University
Hyunseok Oh
Homepage : http://espark.snu.ac.kr
Contents
Development of “Work-hardenable” BMGCs with transformable 2nd
phases
Optimization of work-hardenability in BMGCs with transformable 2nd phases by controlling Vf and MS temp.
1) Fabrication of BMGCs with transformable 2nd phases
2) Evaluation of deformation mechanism in BMGCs
3) Hard ceramic, Soft crystalline, Transformation mediated
Comparison of Work-hardenability depending on 2nd Phases
4) Different martensitic transformation temperature
→ 2 different deformation behaviors of BMGCs depending on 2nd phases
work-softening vs work-hardening behavior → Self healing?
Brief introduction of BMGs and BMG matrix composites
Necessity of work hardenable bulk metallic glass composites
: Metallic Glasses Offer a Unique Combination of High Strength and High Elastic Limit
0.0
0.5
1.0
1.5
2.0
2.5
3.0
Engin
eering S
tress
(G
Pa)
0 2 4 6 8 10 12 14 16
Engineering Strain (%)
“Conventional metal”
- low strength
“Amorphous metal”
- limited plasticity (0~2%)
- catastrophic failure
20㎛ 200㎛
Necessity of work hardenable bulk metallic glass composites
Possibility : Metallic Glasses has an intrinsic plasticity
Ceramic : Broken
Metallic glass : Weaken
Necessity of work hardenable bulk metallic glass composites
200 nm ~ 20 nm
clear boundary between undeformed matrix and shear bands
R
~ 20 nm
HRTEM image of a shear band
Shear deformed areas with the same composition & different density of free volume
Shear bands form by accumulation of defects during deformation.
Ref : Prof. Park
2) Transformation media
→ Work hardening
Douglas C. Hofmann, SCIENCE VOL 329 10 SEPTEMBER 2010
1) Ductile phase
→ Work softening
Necessity of work hardenable bulk metallic glass composites
BMG matrix CuZr B2 Transformation media
Yuan Wu, et al. Adv. Mater. 2010, 22, 2770–2773 [XRD pattern & Morphology of secondary phase before / after tensile test]
Necessity of work hardenable bulk metallic glass composites
Work-hardening behavior of BMGCs in tension
2) Transformation media
→ Work hardening
Douglas C. Hofmann, SCIENCE VOL 329 10 SEPTEMBER 2010
1) Ductile phase
→ Work softening
A
1. Size & Distribution
2. Volume fraction
3. Transformability: Martensitic transformation
Modulated Ex-situ Composite
To develop ultra tough BMGCs : Control the characteristics of 2nd phase
Necessity of work hardenable bulk metallic glass composites
1. Matrix Cu-based system
TiNi ~ Commercialized transformation media
with high performance 2. 2nd phase TiNiCu B2 phase
Preparation of Gas atomized powders
Preparation of metallic glass and SMA powders
-50 0 50 100 150
-0.4
-0.2
0.0
0.2
0.4
Heating
cooling
DSC trace
As -3.9°C
Af 17.2°C
Mf -21.0°C Ms -4.4°C
Temperature(°C)
ΔH=12.6J/g
ΔH=-12.6J/g
Secondary phase : TiNiCu powder B2 B19
200㎛
20 30 40 50 60 70 80
CC
C
Inte
nsi
ty(a
.u.)
2theta(degree)
C
10 20 30 40 50 60 70 80
0
2
4
6
8
10
12
14
16r
avg= 38.9 μm
Particle Size Distribution(Ti50Ni45Cu5)
fra
ctio
n(%
)
radius(um)
XRD
300 350 400 450 500 550 600
-20
-15
-10
-5
0
5
10
DSC
Tg 448°C Tx1 475°C
Temperature(°C)
20 30 40 50 60 70 80
Inte
ns
ity
(a.u
.)
2theta(degree)
XRD
0 20 40 600
2
4
6
8
10
12
14
16
18
fraction(%
)
radius(μm)
Particle Size Distribution(Cu54Ni6Ti18Zr22)
ravg=24.8μm
Matrix : Cu based metallic glass
200㎛
0 20 40 60 800
200
400
600
800
1000
Lo
ad
(uN
)
Displacement(nm)
2um conical tip, 5-2-5s
Conventional
metal
Superelastic property of TiNiCu 2nd phase
Nano-indentation
TiNi(B2)
B2 elastic
B2 B19(B19’)
B19(B19’)
Hysteresis loop : Superelasticity
B2 B19(B19’) reversible martensitic transformation 0
0
Strain
Str
ess
B2 elastic B2 B19’ B19(B19’)
Strain hardening
Pressure
POWDER
Powder
particle Electrical current
Joule heat
Discharge
Vacuum
chamber
Temperature : 440~470°C
Time : 15min
13mm disc, 7mm height
Pressing at Supercooled Liquid Region of mixed powders with high pressure (600MPa)
to consolidate the sample through viscous flow of metallic glass matrix.
Fabrication : Spark plasma sintering
Preparation of BMGC by Spark Plasma Sintering Method
20 30 40 50 60 70 80
30%
20%
10%
0%
C C
Inte
nsity(a
.u.)
2theta(degree)
C
500㎛
0%
500㎛
10%
500㎛
20%
500㎛
30%
XRD pattern SEM image
Ultrasonic measurement
Density(g/cm) v E(GPa) G(GPa) G/K
0% 7.90 0.360 80.6 29.6 0.21
10% 7.77 0.369 74.2 27.1 0.19
20% 7.67 0.374 70.6 25.7 0.18
30% 7.58 0.378 68.4 24.8 0.17
Fabrication : Spark plasma sintering
0.0 1.8 3.6 5.4 7.2 9.00
500
1000
1500
2000
(d)
x=30
(c)
x=20
(a)
x=0
Str
ess(M
Pa)
Strain(%)
Cu-based BMG + x% TiNiCu
(b)
x=10
1×10-4S-1 Uniaxial compression
1.93GPa
1.83GPa 1.86GPa
1.39GPa
2㎜
2㎜
4㎜
1. Large plasticity and Work hardening behavior
2. Fracture crack – propagate through interface of the 2nd phase and matrix
3. Multiple shear bands: initiation & propagation
0%
100μm 100μm
20%
Compression test: Large plasticity and work-hardening behavior
Cu-based BMGC with 20% TiNiCu
- Neutron source
diffractometer,
wave length=1.46Å
- Gauge volume:
2 x 2 x 2 mm3
(along the radial direction)
Deep penetration
depth (several
centimeters in most
materials)
Powerful tool for analyzing internal strain/phase in bulk samples
during deformation
-
Deformation Mechanism of BMGC with transformable 2nd phase
Neutron diffraction
36 37 38 39 40 41 42
0.0
0.2
0.4
0.6
0.8
1.0
No
rma
lize
d In
ten
sity
2theta(degree)
36 37 38 39 40 41 42
0.0
0.2
0.4
0.6
0.8
1.0
No
rma
lize
d In
ten
sity
2theta(degree)
36 37 38 39 40 41 42
0.0
0.2
0.4
0.6
0.8
1.0
No
rma
lize
d In
ten
sity
2theta(degree)
0 1 2 3 4
0
200
400
600
800
1000
1200
1400
1600
1800
2000
Str
ess(M
Pa)
Strain(%)
B2
0MPa
1. M.T. is constrained by horizontal frame of MG matrix because of the imbalance of
Poisson’s ratio during M.T.(~0.5) with elastic loading of MG matrix(~0.33).
Work hardening of BMGCs
In-situ neutron diffraction measurement under compression
Work hardening
Cu-based BMGC with transformable 2nd phase (20% TiNiCu)
34 36 38 40 42 44
0
10
20
30
40
50
60
0kN
A
0kN
0 1 2 3 4
0
200
400
600
800
1000
1200
1400
1600
1800
2000
Str
ess(M
Pa)
Strain(%) 1200MPa
In-situ neutron diffraction measurement under compression
Cu-based BMGC with transformable 2nd phase (20% TiNiCu)
Work hardening
1. M.T. is constrained by horizontal frame of MG matrix because of the imbalance of
Poisson’s ratio during M.T.(~0.5) with elastic loading of MG matrix(~0.33).
Work hardening of BMGCs
36 37 38 39 40 41 42
0.0
0.2
0.4
0.6
0.8
1.0
No
rma
lize
d In
ten
sity
2theta(degree)
36 37 38 39 40 41 42
0.0
0.2
0.4
0.6
0.8
1.0
No
rma
lize
d In
ten
sity
2theta(degree)
36 37 38 39 40 41 42
0.0
0.2
0.4
0.6
0.8
1.0
No
rma
lize
d In
ten
sity
2theta(degree)
B2
34 36 38 40 42 44
0
10
20
30
40
50
60
8.5
kN
A
8.5kN
36 37 38 39 40 41 42
0.0
0.2
0.4
0.6
0.8
1.0
No
rma
lize
d In
ten
sity
2theta(degree)0 1 2 3 4
0
200
400
600
800
1000
1200
1400
1600
1800
2000
Str
ess(M
Pa
)
Strain(%) 1500MPa
In-situ neutron diffraction measurement under compression
Work hardening
Cu-based BMGC with transformable 2nd phase (20% TiNiCu)
2. M.T./slip deformation of 2nd phase are allowed to proceed with formation of shear
bands in the metallic glass matrix near yield strength.
Work hardening of BMGCs
36 37 38 39 40 41 42
0.0
0.2
0.4
0.6
0.8
1.0
No
rma
lize
d In
ten
sity
2theta(degree)
36 37 38 39 40 41 42
0.0
0.2
0.4
0.6
0.8
1.0
No
rma
lize
d In
ten
sity
2theta(degree)
36 37 38 39 40 41 42
0.0
0.2
0.4
0.6
0.8
1.0
No
rma
lize
d In
ten
sity
2theta(degree)
B2
B19
34 36 38 40 42 44
-5
0
5
10
15
20
25
30
35
40
45
50
55
60
12
kN
A
12kN
0 1 2 3 4
0
200
400
600
800
1000
1200
1400
1600
1800
2000
Str
ess(M
Pa)
Strain(%) 1800MPa
2. M.T./slip deformation of 2nd phase are allowed to proceed with formation of shear
bands in the metallic glass matrix near yield strength.
Work hardening of BMGCs
Work hardening
Cu-based BMGC with transformable 2nd phase (20% TiNiCu)
In-situ neutron diffraction measurement under compression
34 36 38 40 42 44
-5
0
5
10
15
20
25
30
35
40
45
50
55
60
13
kN
A
13kN
B2
B19
1. M.T. is constrained by horizontal frame of MG matrix because of the imbalance of
Poisson’s ratio during M.T.(~0.5) with elastic loading of MG matrix (~0.33).
.
Work-hardening of BMGCs with transformable 2nd phases
0 1 2 3 4 5
0
500
1000
1500
2000
Str
ess(M
Pa
)
Strain(%)
λ=2dsinθ , ε= d-d0
d
• Martensitic transformation
didn’t occur during elastic
loading of the composites.
• Lattice strain stopped
increasing at certain stress
level.
37.0 37.5 38.0 38.5 39.0 39.5 40.0 40.5 41.0
0.18
0.36
0.54
0.72
0.90
0
230
340
570
1220
1520
1670
1820
0un
1220re
1670re
2theta(degree)
Inte
nsity
App
lied
stre
ss(M
Pa)
B2
B19
B19’ B19
B19’
0.00 0.05 0.10 0.15
0
200
400
600
800
1000
1200
1400
1600
1800
2000
Str
ess(M
Pa
)Lattice strain(%)
B2
B19,B19'
B2(Unloading)
In-situ neutron diffraction measurement under compression
B2
Str
es
s
Strain
2nd phase
Matrix
Str
es
s
“Strain hardening of 2nd phase contributes to work hardening behavior of BMGC.”
Strain hardening
Str
es
s
Strain
BMGMC
Work hardening
Mechanism of Work-hardening in BMGC with transformable 2nd phase
Bulk metallic glass composite
Hard ceramic, Soft crystalline, Transformation mediated
Comparison of Work-hardenability depending on 2nd Phases
Different martensitic transformation temperature
→ Applying deformation mechanisms to serrated flow
Comparison of Work-hardenability depending on 2nd Phases
H.C.
T.M.
S.C.
𝜎𝑝 = 𝜎 − 𝜎𝑦
𝜀𝑝 = 𝜀 − 𝜀𝑦 −𝜎𝑝
𝐸
• T.M. : Strain hardening
• H.C., S.C. : Strain softening
0 1 2 3 4 5 6 7 8 9 10 11 120
200
400
600
800
1000
1200
1400
1600
1800
2000
2200
T
rue s
tress(M
Pa)
True strain(%)
1919 1817
1725
T.M. H.C. S.C.
Strain hardening(2nd) Work hardening
(T.M. > S.C. > H.C.) (T.M. > S.C. > H.C.)
Higher strain hardening of T.M., then larger work hardenability of BMGMCs
0.0 0.5 1.0 1.5
0
20
40
60
80
100
120
140
160
180
200
220
240
260
Pla
stic s
tre
ss(M
Pa
)
Plastic strain(%)
T.M.
H.C.
S.C.
Comparison of Work-hardenability depending on 2nd Phases
Mechanism of Work-hardening in BMGC with transformable 2nd phase
2.25 2.30 2.35 2.40 2.451944.2
1944.4
1944.6
1944.8
1945.0
1945.2
1945.4
1945.6
True strain(%)
2.45 2.50 2.55
1920
1925
1930
1935
1940
True strain(%)2.09402.09452.09502.09552.09602.09652.09702.09752.09802.0985
1925.5
1926.0
Tru
e s
tress(M
Pa)
True strain(%)
0 1 2 30
200
400
600
800
1000
1200
1400
1600
1800
2000
2200
Tru
e s
tress(M
Pa)
True strain(%)
1919
H.C.
Yield UCS Fracture
0 1 2 3 4 5 6 70
200
400
600
800
1000
1200
1400
1600
1800
2000
2200
Tru
e s
tre
ss(M
Pa
)
True strain(%)
4.70 4.75 4.80 4.85 4.901821.6
1821.8
1822.0
1822.2
1822.4
1822.6
1822.8
1823.0
True strain(%)1.960 1.962 1.964 1.966 1.968
1726.5
1727.0
1727.5
1728.0
1728.5
Tru
e s
tress(M
Pa)
True strain(%)
5.0 5.5 6.0
1812
1814
1816
1818
1820
1822
1824
True strain(%)
S.C.
1725
Yield UCS Fracture
0 1 2 3 4 5 60
200
400
600
800
1000
1200
1400
1600
1800
2000
2200
Tru
e s
tre
ss(M
Pa
)
True strain(%)
3.90 3.95 4.00 4.05 4.101998.0
1998.2
1998.4
1998.6
1998.8
1999.0
1999.2
1999.4
True strain(%)
1.90 1.95 2.00 2.05 2.10 2.151810
1820
1830
1840
1850
1860
1870
Tru
e s
tress(M
Pa)
True strain(%)
4.30 4.35 4.40 4.45 4.50 4.55 4.60
1976
1980
1984
1988
1992
1996
True strain(%)
T.M.
1817
Yield UCS Fracture
Serrated flow
Δσ increases continuously
Δσ increases from 0 to 0.3~0.8 MPa and becomes saturated S.C. & T.M.
Why?
H.C.
Δσ~0.8
Ability of absorbing dissipated energy : T.M. > S.C. > H.C.
Δσ~10 Δσ~0 Δσ~0 Δσ~0.5 Δσ~0.5 Δσ~0 Δσ~0.3 Δσ~0.5
Str
ess
Composite
Matrix
2nd phase
Displacement
σy
Latt
ice s
train
O
Str
ess
Displacement
Latt
ice s
train
σy Composite
Matrix
2nd phase
σy
Composite
Matrix
2nd phase
Displacement
Latt
ice s
train
Str
ess
O O
Elastic Plastic Elastic Plastic Elastic Plastic ③ ① ② ④ ⑤ ③ ① ② ④ ⑤ ③ ① ② ④ ⑤
2nd phase – brittle fracture 2nd phase – strain hardening +martensitic transformation
Soft crystalline 2nd phase Hard ceramic 2nd phase Transformable 2nd phase
Metallic glass
SC
Metallic glass
SMA(M)
Metallic glass
HC
2nd phase – strain hardening
Str
ess
Composite
Matrix
2nd phase
Displacement
σy
Latt
ice s
train
O
Str
ess
Displacement
Latt
ice s
train
σy Composite
Matrix
2nd phase
σy
Composite
Matrix
2nd phase
Displacement
Latt
ice s
train
Str
ess
O O
Elastic Plastic Elastic Plastic Elastic Plastic ③ ① ② ④ ⑤ ③ ① ② ④ ⑤ ③ ① ② ④ ⑤
Soft crystalline 2nd phase Hard ceramic 2nd phase Transformable 2nd phase
Absorption mechanism of dissipated energy during shear banding
Hard ceramic None
Soft crystalline Strain hardening
Transformation mediated Martensitic transformation, Strain hardening
2nd phase – brittle fracture 2nd phase – strain hardening +martensitic transformation
2nd phase – strain hardening
-50 0 50 100-4
-3
-2
-1
0
1
2
3
4
Cooling
HeatingAs -2.4°C
Af 11.5°C
Mf -18.2°C Ms -2.7°C
Temperature(°C)
B (Ms= -3)
-50 0 50 100
-1
0
1
Cooling
HeatingAs -13.5°C Af 36.8°C
Mf -5.7°C Ms 32.4°C
Temperature(°C)
A (Ms= 32) #1 #2 #3
-10
0
10
20
30
Ms
Te
mp
era
ture
(oC
)
Yielding : Martensitic transformation
A (Ms= 32) B (Ms= -3)
C (Ms= -16)
Change the characteristics of 2nd phase
1. Different characteristic of Martensitic Transformation (A, B, C)
2. Same weight fraction (~volume fraction) of 2nd phase (20%)
Manipulation of Work-hardenability by Controlling 2nd Phases
-50 0 50 100
-1
0
1
Cooling
HeatingAs -25.2°C Af -4.4°C
Mf -38.5°C Ms -15.95°C
Temperature(°C)
C (Ms= -16)
-20 -10 0 10 20 30 40
1600
1800
2000
2200
2400
2600
2800
3000
3200
3400
3600
3800
4000
4200
4400
4600
4800
5000
Str
ess o
f m
art
en
sitic
tra
nsfo
rma
tio
n(M
Pa
)
Ms(degree)
C
B
A
Str
ess
A
B
C
Strain
Er(GPa) H(GPa) MT stress(GPa) Strain hardening
A 61.2±3.1 4.88±0.26 2.10±0.19
B 58.4±3.4 3.92±0.23 2.43±0.56
C 57.1±2.3 3.99±0.29 3.24±0.22
Strain hardening component
Measurement of martensitic transformation stress : Nano-indentation
Manipulation of Work-hardenability by Controlling 2nd Phases
𝜎𝑝 = 𝜎 − 𝜎𝑦
𝜀𝑝 = 𝜀 − 𝜀𝑦 −𝜎𝑝
𝐸
* “Work hardenability” ∝
“Strain hardenability after M.T.”
0 1 2 3 4 5 6 70
200
400
600
800
1000
1200
1400
1600
1800
2000
2200
T
rue
str
ess(M
Pa
)
True strain(%)
1693
1817
1647
A B C
Ms(below R.T.) M.T. stress Strain hardening(2nd) Work hardening
(A > B > C // D) (A < B < C // D) (A > B > C // D) (A > B > C // D)
Higher Ms & Easier M.T. of 2nd phase, then larger work hardenability of BMGMCs
Manipulation of Work-hardenability by Controlling 2nd Phases
A
B
C
0.0 0.5 1.0 1.5
0
50
100
150
200
250
Pla
stic s
tress(M
Pa
)
Plastic strain(%)
1. Newly developed ex-situ BMGCs with transformable TiNiCu 2nd phase
exhibit large plasticity and superior work-hardening behavior.
2. Work hardening of BMGCs with transformable 2nd phase is from
delayed strain hardening of 2nd phase after matrix yielding, which
can be evaluated by in-situ neutron diffraction measurement
under compression test.
4. We can optimize work-hardenability of BMGCs by controlling
the fraction & martensitic transformability of 2nd phase in BMGC.
Conclusions
→ “Work hardenability” ∝ “Strain hardenability after M.T.”
3. The reason of superior work hardenability of BMGMCs with
transformation mediated 2nd phase is supposed to come from
higher performance of absorbing dissipated energy of shear
band by strain hardening and martensitic transformation.
Thank you for your kind attention
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