Grain Boundary Mobility in High Entropy Alloys …...2011/10/18 · Motivation Praveen et al., J....
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Grain Boundary Effects in High Entropy Alloys: Insights from Atomistic Computer Simulations D. Utt , A. Stukowski, K. Albe // | Daniel Utt | [email protected] |
Transcript of Grain Boundary Mobility in High Entropy Alloys …...2011/10/18 · Motivation Praveen et al., J....
Grain Boundary Effects in High Entropy Alloys:Insights from Atomistic Computer SimulationsD. Utt, A. Stukowski, K. Albe
11/10/2018 | Daniel Utt | [email protected] | 1
Motivation
Praveen et al., J. Alloy. Comp., 2016, 662
I Growth factor: df/d0
I HEA grain growth factor verysmall
I Hall-Petch law
What is the origin ofthe reduced grain growth?
11/10/2018 | Daniel Utt | [email protected] | 2
Motivation
Praveen et al., J. Alloy. Comp., 2016, 662
I Growth factor: df/d0I HEA grain growth factor verysmall
I Hall-Petch law
What is the origin ofthe reduced grain growth?
11/10/2018 | Daniel Utt | [email protected] | 2
Motivation
Praveen et al., J. Alloy. Comp., 2016, 662
I Growth factor: df/d0I HEA grain growth factor verysmall
I Hall-Petch law
What is the origin ofthe reduced grain growth?
11/10/2018 | Daniel Utt | [email protected] | 2
Motivation
Praveen et al., J. Alloy. Comp., 2016, 662
I Growth factor: df/d0I HEA grain growth factor verysmall
I Hall-Petch law
What is the origin ofthe reduced grain growth?
11/10/2018 | Daniel Utt | [email protected] | 2
Possible Causes for Reduced Grain Growth
I Zener pinning on carbides oroxides
I Reduced GB mobility caused bysolute drag
I Reduced driving force due to GBsegregation
I Local lattice distortions
Zou et al., Nano Lett., 2017, 17 (3)Praveen et al., J. Alloy. Comp., 2016, 662Liu et al., Scr. Mater., 2013, 68Zhou et al., Scr. Mater., 2016, 124
11/10/2018 | Daniel Utt | [email protected] | 3
Possible Causes for Reduced Grain Growth
I Zener pinning on carbides oroxides
I Reduced GB mobility caused bysolute drag
I Reduced driving force due to GBsegregation
I Local lattice distortions
Zou et al., Nano Lett., 2017, 17 (3)Praveen et al., J. Alloy. Comp., 2016, 662Liu et al., Scr. Mater., 2013, 68Zhou et al., Scr. Mater., 2016, 124
11/10/2018 | Daniel Utt | [email protected] | 3
Possible Causes for Reduced Grain Growth
I Zener pinning on carbides oroxides
I Reduced GB mobility caused bysolute drag
I Reduced driving force due to GBsegregation
I Local lattice distortions
Zou et al., Nano Lett., 2017, 17 (3)Praveen et al., J. Alloy. Comp., 2016, 662Liu et al., Scr. Mater., 2013, 68Zhou et al., Scr. Mater., 2016, 124
11/10/2018 | Daniel Utt | [email protected] | 3
Possible Causes for Reduced Grain Growth
I Zener pinning on carbides oroxides
I Reduced GB mobility caused bysolute drag
I Reduced driving force due to GBsegregation
I Local lattice distortions
Zou et al., Nano Lett., 2017, 17 (3)Praveen et al., J. Alloy. Comp., 2016, 662Liu et al., Scr. Mater., 2013, 68Zhou et al., Scr. Mater., 2016, 124
11/10/2018 | Daniel Utt | [email protected] | 3
Methodology
I Atomistic simulations using lammps
I Equimolar FCC CuNiCoFe HEAI Random configuration (Rand. . . . )I Chemical equilibration using hybrid VC-SGCMC/MD
I EAM interatomic potentialI Compare to pure Cu, Ni, and ‘average atom’
Cu Ni Co Fe
Average Atom(Avg.-Atom)
www.lammps.sandia.govZhou et al., Phys. Rev. B, 2004, 69Koch et al., JAP, 2017, 122Sadigh et al., Phys. Rev. B, 2012, 85Koch et al., JAP, 2017, 122Varvenne et al., Phys. Rev. B, 2016, 93
11/10/2018 | Daniel Utt | [email protected] | 4
Methodology
I Atomistic simulations using lammpsI Equimolar FCC CuNiCoFe HEA
I Random configuration (Rand. . . . )I Chemical equilibration using hybrid VC-SGCMC/MD
I EAM interatomic potentialI Compare to pure Cu, Ni, and ‘average atom’
Cu Ni Co Fe
Average Atom(Avg.-Atom)
www.lammps.sandia.govZhou et al., Phys. Rev. B, 2004, 69Koch et al., JAP, 2017, 122Sadigh et al., Phys. Rev. B, 2012, 85Koch et al., JAP, 2017, 122Varvenne et al., Phys. Rev. B, 2016, 93
11/10/2018 | Daniel Utt | [email protected] | 4
Methodology
I Atomistic simulations using lammpsI Equimolar FCC CuNiCoFe HEA
I Random configuration (Rand. . . . )I Chemical equilibration using hybrid VC-SGCMC/MD
I EAM interatomic potential
I Compare to pure Cu, Ni, and ‘average atom’
Cu Ni Co Fe
Average Atom(Avg.-Atom)
www.lammps.sandia.govZhou et al., Phys. Rev. B, 2004, 69Koch et al., JAP, 2017, 122Sadigh et al., Phys. Rev. B, 2012, 85Koch et al., JAP, 2017, 122Varvenne et al., Phys. Rev. B, 2016, 93
11/10/2018 | Daniel Utt | [email protected] | 4
Methodology
I Atomistic simulations using lammpsI Equimolar FCC CuNiCoFe HEA
I Random configuration (Rand. . . . )I Chemical equilibration using hybrid VC-SGCMC/MD
I EAM interatomic potentialI Compare to pure Cu, Ni, and ‘average atom’
Cu Ni Co Fe
Average Atom(Avg.-Atom)
www.lammps.sandia.govZhou et al., Phys. Rev. B, 2004, 69Koch et al., JAP, 2017, 122Sadigh et al., Phys. Rev. B, 2012, 85Koch et al., JAP, 2017, 122Varvenne et al., Phys. Rev. B, 2016, 93
11/10/2018 | Daniel Utt | [email protected] | 4
Methodology
I Atomistic simulations using lammpsI Equimolar FCC CuNiCoFe HEA
I Random configuration (Rand. . . . )I Chemical equilibration using hybrid VC-SGCMC/MD
I EAM interatomic potentialI Compare to pure Cu, Ni, and ‘average atom’
Cu Ni Co Fe
Average Atom(Avg.-Atom)
www.lammps.sandia.govZhou et al., Phys. Rev. B, 2004, 69Koch et al., JAP, 2017, 122Sadigh et al., Phys. Rev. B, 2012, 85Koch et al., JAP, 2017, 122Varvenne et al., Phys. Rev. B, 2016, 93
11/10/2018 | Daniel Utt | [email protected] | 4
Lattice Distortions
What is the magnitude of theintrinsic lattice distortions?
0 25 500
2
4
6
8
10
Temperature /K
Meandisplacement/pm
Cu NiAvg.-atom
0 25 500
2
4
6
8
10
Temperature /K
Meandisplacement/pm
Cu Ni
Avg.-atom Rand.CuNiCoFe
0 250 500 750 10000
10
20
30
40
50
Temperature /K
Meandisplacement/pm
CuNiAvg.-atomRand.CuNiCoFe
Intrinsic lattice distortions are measurable at 0 K,but become negligible at higher temperatures.
11/10/2018 | Daniel Utt | [email protected] | 5
Lattice Distortions
What is the magnitude of theintrinsic lattice distortions?
0 25 500
2
4
6
8
10
Temperature /K
Meandisplacement/pm
Cu NiAvg.-atom
0 25 500
2
4
6
8
10
Temperature /K
Meandisplacement/pm
Cu Ni
Avg.-atom Rand.CuNiCoFe
0 250 500 750 10000
10
20
30
40
50
Temperature /K
Meandisplacement/pm
CuNiAvg.-atomRand.CuNiCoFe
Intrinsic lattice distortions are measurable at 0 K,but become negligible at higher temperatures.
11/10/2018 | Daniel Utt | [email protected] | 5
Lattice Distortions
What is the magnitude of theintrinsic lattice distortions?
0 25 500
2
4
6
8
10
Temperature /K
Meandisplacement/pm
Cu NiAvg.-atom
0 25 500
2
4
6
8
10
Temperature /K
Meandisplacement/pm
Cu Ni
Avg.-atom Rand.CuNiCoFe
0 250 500 750 10000
10
20
30
40
50
Temperature /K
Meandisplacement/pm
CuNiAvg.-atomRand.CuNiCoFe
Intrinsic lattice distortions are measurable at 0 K,but become negligible at higher temperatures.
11/10/2018 | Daniel Utt | [email protected] | 5
Lattice Distortions
What is the magnitude of theintrinsic lattice distortions?
0 25 500
2
4
6
8
10
Temperature /K
Meandisplacement/pm
Cu NiAvg.-atom
0 25 500
2
4
6
8
10
Temperature /K
Meandisplacement/pm
Cu Ni
Avg.-atom Rand.CuNiCoFe
0 250 500 750 10000
10
20
30
40
50
Temperature /K
Meandisplacement/pm
CuNiAvg.-atomRand.CuNiCoFe
Intrinsic lattice distortions are measurable at 0 K,but become negligible at higher temperatures.
11/10/2018 | Daniel Utt | [email protected] | 5
Lattice Distortions
What is the magnitude of theintrinsic lattice distortions?
0 25 500
2
4
6
8
10
Temperature /K
Meandisplacement/pm
Cu NiAvg.-atom
0 25 500
2
4
6
8
10
Temperature /K
Meandisplacement/pm
Cu Ni
Avg.-atom Rand.CuNiCoFe
0 250 500 750 10000
10
20
30
40
50
Temperature /K
Meandisplacement/pm
CuNiAvg.-atomRand.CuNiCoFe
Intrinsic lattice distortions are measurable at 0 K,but become negligible at higher temperatures.
11/10/2018 | Daniel Utt | [email protected] | 5
Σ 11 (332) 〈110〉 STGB0K Structures
Is there a structural difference forthe GBs in the different materials?
Cu Ni
Avg.-atom
Rand.
CuNiCoFe
Rand.
CuNiCoFe
FCC Other
Almost no structural difference forthis STGB in the different materials.
11/10/2018 | Daniel Utt | [email protected] | 6
Σ 11 (332) 〈110〉 STGB0K Structures
Is there a structural difference forthe GBs in the different materials?
Cu Ni
Avg.-atom
Rand.
CuNiCoFe
Rand.
CuNiCoFe
FCC Other
Almost no structural difference forthis STGB in the different materials.
11/10/2018 | Daniel Utt | [email protected] | 6
Σ 11 (332) 〈110〉 STGB0K Structures
Is there a structural difference forthe GBs in the different materials?
Cu Ni
Avg.-atom
Rand.
CuNiCoFe
Rand.
CuNiCoFe
FCC Other
Almost no structural difference forthis STGB in the different materials.
11/10/2018 | Daniel Utt | [email protected] | 6
Σ 11 (332) 〈110〉 STGB0K Structures
Is there a structural difference forthe GBs in the different materials?
Cu Ni
Avg.-atom
Rand.
CuNiCoFe
Rand.
CuNiCoFe
FCC Other
Almost no structural difference forthis STGB in the different materials.
11/10/2018 | Daniel Utt | [email protected] | 6
Σ 11 (332) 〈110〉 STGB0K Structures
Is there a structural difference forthe GBs in the different materials?
Cu Ni
Avg.-atom
Rand.
CuNiCoFe
Rand.
CuNiCoFe
FCC Other
Almost no structural difference forthis STGB in the different materials.
11/10/2018 | Daniel Utt | [email protected] | 6
Σ 11 (332) 〈110〉 STGB0K Structures
Is there a structural difference forthe GBs in the different materials?
Cu Ni
Avg.-atom
Rand.
CuNiCoFe
Rand.
CuNiCoFe
FCC Other
Almost no structural difference forthis STGB in the different materials.
11/10/2018 | Daniel Utt | [email protected] | 6
Synthetic Driving Force
What are the GB mobilities for the differentmaterials under driven conditions?
Synthetic driving pressure:
P = ∆eΩ
GB Mobility:
M = vP
M(T) = M∞ exp(–QmkBT
)
Grain 1
Grain 2∆e: 0 15meV
Janssens et al., Nat. Mater., 2006, 5
11/10/2018 | Daniel Utt | [email protected] | 7
Synthetic Driving Force
What are the GB mobilities for the differentmaterials under driven conditions?
Synthetic driving pressure:
P = ∆eΩ
GB Mobility:
M = vP
M(T) = M∞ exp(–QmkBT
)
Grain 1
Grain 2∆e: 0 15meV
Janssens et al., Nat. Mater., 2006, 5
11/10/2018 | Daniel Utt | [email protected] | 7
Synthetic Driving Force
What are the GB mobilities for the differentmaterials under driven conditions?
Synthetic driving pressure:
P = ∆eΩ
GB Mobility:
M = vP
M(T) = M∞ exp(–QmkBT
)
Grain 1
Grain 2∆e: 0 15meV
Janssens et al., Nat. Mater., 2006, 5
11/10/2018 | Daniel Utt | [email protected] | 7
Synthetic Driving Force
What are the GB mobilities for the differentmaterials under driven conditions?
Synthetic driving pressure:
P = ∆eΩ
GB Mobility:
M = vP
M(T) = M∞ exp(–QmkBT
)
Grain 1
Grain 2∆e: 0 15meV
Janssens et al., Nat. Mater., 2006, 5
11/10/2018 | Daniel Utt | [email protected] | 7
Σ 11 (332) 〈110〉 STGBMobility
0.75 1.00 1.2510–8
10–7 Cu
Ni
∆e = 15meV
Inverse temperature /(1000/K)
GBmobility/(m4 /Js)
0.75 1.00 1.2510–8
10–7 Cu
Ni
Avg.-atom
Rand.CuNiCoFe
∆e = 15meV
Inverse temperature /(1000/K)
GBmobility/(m4 /Js)
Local chemical disorder does not significantlyalter the mobility of this STGB.
11/10/2018 | Daniel Utt | [email protected] | 8
Σ 11 (332) 〈110〉 STGBMobility
0.75 1.00 1.2510–8
10–7 Cu
Ni
∆e = 15meV
Inverse temperature /(1000/K)
GBmobility/(m4 /Js)
0.75 1.00 1.2510–8
10–7 Cu
Ni
Avg.-atom
Rand.CuNiCoFe
∆e = 15meV
Inverse temperature /(1000/K)
GBmobility/(m4 /Js)
Local chemical disorder does not significantlyalter the mobility of this STGB.
11/10/2018 | Daniel Utt | [email protected] | 8
Σ 11 (332) 〈110〉 STGBMobility
0.75 1.00 1.2510–8
10–7 Cu
Ni
∆e = 15meV
Inverse temperature /(1000/K)
GBmobility/(m4 /Js)
0.75 1.00 1.2510–8
10–7 Cu
Ni
Avg.-atom
Rand.CuNiCoFe
∆e = 15meV
Inverse temperature /(1000/K)
GBmobility/(m4 /Js)
Local chemical disorder does not significantlyalter the mobility of this STGB.
11/10/2018 | Daniel Utt | [email protected] | 8
Σ 11 (332) 〈110〉 STGBSegregation & Mobility
0.2
0.4 Cu
00.2
0.40.6
1300K to 1500K
T ↑
0 20 400
0.5
1.0Cu
z position /nm0 200 400
0
1
2
Time /ps
T = 1300 K∆e = 15meVT = 800 K∆e = 25meV
Molarfraction/(—)
GBtraveldistance/(nm
)
0.2
0.4 Cu
00.2
0.40.6
1300K to 1500K
T ↑
0 20 400
0.5
1.0Cu
z position /nm0 200 400
0
1
2
Time /ps
Molarfraction/(—)
GBtraveldistance/(nm
)
0.2
0.4 Cu
00.2
0.40.6
1300K to 1500K
T ↑
0 20 400
0.5
1.0
z position /nm0 200 400
0
1
2
Time /ps
Molarfraction/(—)
GBtraveldistance/(nm
)
0.2
0.4 Cu
00.2
0.40.6
0 20 400
0.5
1.0
z position /nm0 200 400
0
1
2
Time /ps
Molarfraction/(—)
GBtraveldistance/(nm
)
How is the mobility of this STGBaltered by segregation?Segregation strongly inhibitsthe migration of this STGB.
11/10/2018 | Daniel Utt | [email protected] | 9
Σ 11 (332) 〈110〉 STGBSegregation & Mobility
0.2
0.4 Cu
00.2
0.40.6
1300K to 1500K
T ↑
0 20 400
0.5
1.0Cu
z position /nm0 200 400
0
1
2
Time /ps
T = 1300 K∆e = 15meVT = 800 K∆e = 25meV
Molarfraction/(—)
GBtraveldistance/(nm
)
0.2
0.4 Cu
00.2
0.40.6
1300K to 1500K
T ↑
0 20 400
0.5
1.0Cu
z position /nm0 200 400
0
1
2
Time /ps
Molarfraction/(—)
GBtraveldistance/(nm
)
0.2
0.4 Cu
00.2
0.40.6
1300K to 1500K
T ↑
0 20 400
0.5
1.0
z position /nm0 200 400
0
1
2
Time /ps
Molarfraction/(—)
GBtraveldistance/(nm
)
0.2
0.4 Cu
00.2
0.40.6
0 20 400
0.5
1.0
z position /nm0 200 400
0
1
2
Time /ps
Molarfraction/(—)
GBtraveldistance/(nm
)
How is the mobility of this STGBaltered by segregation?Segregation strongly inhibitsthe migration of this STGB.
11/10/2018 | Daniel Utt | [email protected] | 9
Σ 11 (332) 〈110〉 STGBSegregation & Mobility
0.2
0.4 Cu
00.2
0.40.6
1300K to 1500K
T ↑
0 20 400
0.5
1.0Cu
z position /nm0 200 400
0
1
2
Time /ps
T = 1300 K∆e = 15meVT = 800 K∆e = 25meV
Molarfraction/(—)
GBtraveldistance/(nm
)
0.2
0.4 Cu
00.2
0.40.6
1300K to 1500K
T ↑
0 20 400
0.5
1.0Cu
z position /nm0 200 400
0
1
2
Time /ps
Molarfraction/(—)
GBtraveldistance/(nm
)
0.2
0.4 Cu
00.2
0.40.6
1300K to 1500K
T ↑
0 20 400
0.5
1.0
z position /nm0 200 400
0
1
2
Time /ps
Molarfraction/(—)
GBtraveldistance/(nm
)
0.2
0.4 Cu
00.2
0.40.6
0 20 400
0.5
1.0
z position /nm0 200 400
0
1
2
Time /ps
Molarfraction/(—)
GBtraveldistance/(nm
)
How is the mobility of this STGBaltered by segregation?Segregation strongly inhibitsthe migration of this STGB.
11/10/2018 | Daniel Utt | [email protected] | 9
Σ 11 (332) 〈110〉 STGBSegregation & Mobility
0.2
0.4 Cu
00.2
0.40.6
1300K to 1500K
T ↑
0 20 400
0.5
1.0Cu
z position /nm0 200 400
0
1
2
Time /ps
T = 1300 K∆e = 15meVT = 800 K∆e = 25meV
Molarfraction/(—)
GBtraveldistance/(nm
)
0.2
0.4 Cu
00.2
0.40.6
1300K to 1500K
T ↑
0 20 400
0.5
1.0Cu
z position /nm0 200 400
0
1
2
Time /ps
Molarfraction/(—)
GBtraveldistance/(nm
)
0.2
0.4 Cu
00.2
0.40.6
1300K to 1500K
T ↑
0 20 400
0.5
1.0
z position /nm0 200 400
0
1
2
Time /ps
Molarfraction/(—)
GBtraveldistance/(nm
)
0.2
0.4 Cu
00.2
0.40.6
0 20 400
0.5
1.0
z position /nm0 200 400
0
1
2
Time /ps
Molarfraction/(—)
GBtraveldistance/(nm
)
How is the mobility of this STGBaltered by segregation?Segregation strongly inhibitsthe migration of this STGB.
11/10/2018 | Daniel Utt | [email protected] | 9
Σ 11 (332) 〈110〉 STGBSegregation & Mobility
0.2
0.4 Cu
00.2
0.40.6
1300K to 1500K
T ↑
0 20 400
0.5
1.0Cu
z position /nm0 200 400
0
1
2
Time /ps
T = 1300 K∆e = 15meVT = 800 K∆e = 25meV
Molarfraction/(—)
GBtraveldistance/(nm
)
0.2
0.4 Cu
00.2
0.40.6
1300K to 1500K
T ↑
0 20 400
0.5
1.0Cu
z position /nm0 200 400
0
1
2
Time /ps
Molarfraction/(—)
GBtraveldistance/(nm
)
0.2
0.4 Cu
00.2
0.40.6
1300K to 1500K
T ↑
0 20 400
0.5
1.0
z position /nm0 200 400
0
1
2
Time /ps
Molarfraction/(—)
GBtraveldistance/(nm
)
0.2
0.4 Cu
00.2
0.40.6
0 20 400
0.5
1.0
z position /nm0 200 400
0
1
2
Time /ps
Molarfraction/(—)
GBtraveldistance/(nm
)
How is the mobility of this STGBaltered by segregation?Segregation strongly inhibitsthe migration of this STGB.
11/10/2018 | Daniel Utt | [email protected] | 9
Σ 11 (332) 〈110〉 STGBSegregation & Mobility
0.2
0.4 Cu
00.2
0.40.6
1300K to 1500K
T ↑
0 20 400
0.5
1.0Cu
z position /nm0 200 400
0
1
2
Time /ps
T = 1300 K∆e = 15meVT = 800 K∆e = 25meV
Molarfraction/(—)
GBtraveldistance/(nm
)
0.2
0.4 Cu
00.2
0.40.6
1300K to 1500K
T ↑
0 20 400
0.5
1.0Cu
z position /nm0 200 400
0
1
2
Time /ps
Molarfraction/(—)
GBtraveldistance/(nm
)
0.2
0.4 Cu
00.2
0.40.6
1300K to 1500K
T ↑
0 20 400
0.5
1.0
z position /nm0 200 400
0
1
2
Time /ps
Molarfraction/(—)
GBtraveldistance/(nm
)
0.2
0.4 Cu
00.2
0.40.6
0 20 400
0.5
1.0
z position /nm0 200 400
0
1
2
Time /ps
Molarfraction/(—)
GBtraveldistance/(nm
)
How is the mobility of this STGBaltered by segregation?Segregation strongly inhibitsthe migration of this STGB.
11/10/2018 | Daniel Utt | [email protected] | 9
Nanocrystalline SamplesExpected Grain Growth Rate
How do these findings transferto large scale samples containinggeneral GBs?
GB velocity:
v = M · F
Curvature driven GG:
F = 2γr
0.75 1.00 1.2510–8
10–7 Cu
Ni
Avg.-atom
Rand.CuNiCoFe
Σ 11 (332) 〈110〉 STGB∆e = 15meV
Inverse temperature /(1000/K)
GBmobility/(m4 /Js)
0.75 1.00 1.2510–8
10–7 Cu
Ni
Avg.-atom
Rand.CuNiCoFe
Σ 11 (332) 〈110〉 STGB∆e = 15meV
Inverse temperature /(1000/K)
GBmobility/(m4 /Js)
0
1
2
3
t = 1 ns; d0 = 15 nmT = 800K
Cu
Seg.CuNiCoFe
Rand.CuNiCoFe
Avg.-Atom Ni
Sample
Excessenergy/(Jm
–2)
11/10/2018 | Daniel Utt | [email protected] | 10
Nanocrystalline SamplesExpected Grain Growth Rate
How do these findings transferto large scale samples containinggeneral GBs?
GB velocity:
v = M · F
Curvature driven GG:
F = 2γr
0.75 1.00 1.2510–8
10–7 Cu
Ni
Avg.-atom
Rand.CuNiCoFe
Σ 11 (332) 〈110〉 STGB∆e = 15meV
Inverse temperature /(1000/K)
GBmobility/(m4 /Js)
0.75 1.00 1.2510–8
10–7 Cu
Ni
Avg.-atom
Rand.CuNiCoFe
Σ 11 (332) 〈110〉 STGB∆e = 15meV
Inverse temperature /(1000/K)
GBmobility/(m4 /Js)
0
1
2
3
t = 1 ns; d0 = 15 nmT = 800K
Cu
Seg.CuNiCoFe
Rand.CuNiCoFe
Avg.-Atom Ni
Sample
Excessenergy/(Jm
–2)
11/10/2018 | Daniel Utt | [email protected] | 10
Nanocrystalline SamplesExpected Grain Growth Rate
How do these findings transferto large scale samples containinggeneral GBs?
GB velocity:
v = M · F
Curvature driven GG:
F = 2γr
0.75 1.00 1.2510–8
10–7 Cu
Ni
Avg.-atom
Rand.CuNiCoFe
Σ 11 (332) 〈110〉 STGB∆e = 15meV
Inverse temperature /(1000/K)
GBmobility/(m4 /Js)
0.75 1.00 1.2510–8
10–7 Cu
Ni
Avg.-atom
Rand.CuNiCoFe
Σ 11 (332) 〈110〉 STGB∆e = 15meV
Inverse temperature /(1000/K)
GBmobility/(m4 /Js)
0
1
2
3
t = 1 ns; d0 = 15 nmT = 800K
Cu
Seg.CuNiCoFe
Rand.CuNiCoFe
Avg.-Atom Ni
Sample
Excessenergy/(Jm
–2)
11/10/2018 | Daniel Utt | [email protected] | 10
Nanocrystalline SamplesExpected Grain Growth Rate
How do these findings transferto large scale samples containinggeneral GBs?
GB velocity:
v = M · F
Curvature driven GG:
F = 2γr
0.75 1.00 1.2510–8
10–7 Cu
Ni
Avg.-atom
Rand.CuNiCoFe
Σ 11 (332) 〈110〉 STGB∆e = 15meV
Inverse temperature /(1000/K)
GBmobility/(m4 /Js)
0.75 1.00 1.2510–8
10–7 Cu
Ni
Avg.-atom
Rand.CuNiCoFe
Σ 11 (332) 〈110〉 STGB∆e = 15meV
Inverse temperature /(1000/K)
GBmobility/(m4 /Js)
0
1
2
3
t = 1 ns; d0 = 15 nmT = 800K
Cu
Seg.CuNiCoFe
Rand.CuNiCoFe
Avg.-Atom Ni
Sample
Excessenergy/(Jm
–2)
11/10/2018 | Daniel Utt | [email protected] | 10
Nanocrystalline SamplesExpected Grain Growth Rate
How do these findings transferto large scale samples containinggeneral GBs?
GB velocity:
v = M · F
Curvature driven GG:
F = 2γr0.75 1.00 1.25
10–8
10–7 Cu
Ni
Avg.-atom
Rand.CuNiCoFe
Σ 11 (332) 〈110〉 STGB∆e = 15meV
Inverse temperature /(1000/K)
GBmobility/(m4 /Js)
0.75 1.00 1.2510–8
10–7 Cu
Ni
Avg.-atom
Rand.CuNiCoFe
Σ 11 (332) 〈110〉 STGB∆e = 15meV
Inverse temperature /(1000/K)
GBmobility/(m4 /Js)
0
1
2
3
t = 1 ns; d0 = 15 nmT = 800K
Cu
Seg.CuNiCoFe
Rand.CuNiCoFe
Avg.-Atom Ni
Sample
Excessenergy/(Jm
–2)
11/10/2018 | Daniel Utt | [email protected] | 10
Nanocrystalline SamplesExpected Grain Growth Rate
How do these findings transferto large scale samples containinggeneral GBs?
GB velocity:
v = M · F
Curvature driven GG:
F = 2γr0.75 1.00 1.25
10–8
10–7 Cu
Ni
Avg.-atom
Rand.CuNiCoFe
Σ 11 (332) 〈110〉 STGB∆e = 15meV
Inverse temperature /(1000/K)
GBmobility/(m4 /Js)
0.75 1.00 1.2510–8
10–7 Cu
Ni
Avg.-atom
Rand.CuNiCoFe
Σ 11 (332) 〈110〉 STGB∆e = 15meV
Inverse temperature /(1000/K)
GBmobility/(m4 /Js)
0
1
2
3
t = 1 ns; d0 = 15 nmT = 800K
Cu
Seg.CuNiCoFe
Rand.CuNiCoFe
Avg.-Atom Ni
Sample
Excessenergy/(Jm
–2)
11/10/2018 | Daniel Utt | [email protected] | 10
Nanocrystalline SamplesGrain Diameter Evolution
0 1 2 3
16
18
20
22Cu
Ni
d0 = 15 nmT = 800K
Time /ns
Graindiam
eter/nm
0 1 2 3
Avg.-atom
Rand.CuNiCoFe
d0 = 15 nmT = 800K
Time /ns0 1 2 3
Seg.CuNiCoFe
d0 = 15 nmT = 800K
Time /ns
Rand. CuNiCoFe alloy has a low GB mobilityand driving force – leading to a low GG rate.Segregation strongly inhibits grain growth.
11/10/2018 | Daniel Utt | [email protected] | 11
Nanocrystalline SamplesGrain Diameter Evolution
0 1 2 3
16
18
20
22Cu
Ni
d0 = 15 nmT = 800K
Time /ns
Graindiam
eter/nm
0 1 2 3
Avg.-atom
Rand.CuNiCoFe
d0 = 15 nmT = 800K
Time /ns0 1 2 3
Seg.CuNiCoFe
d0 = 15 nmT = 800K
Time /ns
Rand. CuNiCoFe alloy has a low GB mobilityand driving force – leading to a low GG rate.Segregation strongly inhibits grain growth.
11/10/2018 | Daniel Utt | [email protected] | 11
Nanocrystalline SamplesGrain Diameter Evolution
0 1 2 3
16
18
20
22Cu
Ni
d0 = 15 nmT = 800K
Time /ns
Graindiam
eter/nm
0 1 2 3
Avg.-atom
Rand.CuNiCoFe
d0 = 15 nmT = 800K
Time /ns0 1 2 3
Seg.CuNiCoFe
d0 = 15 nmT = 800K
Time /ns
Rand. CuNiCoFe alloy has a low GB mobilityand driving force – leading to a low GG rate.Segregation strongly inhibits grain growth.
11/10/2018 | Daniel Utt | [email protected] | 11
Nanocrystalline SamplesGrain Diameter Evolution
0 1 2 3
16
18
20
22Cu
Ni
d0 = 15 nmT = 800K
Time /ns
Graindiam
eter/nm
0 1 2 3
Avg.-atom
Rand.CuNiCoFe
d0 = 15 nmT = 800K
Time /ns0 1 2 3
Seg.CuNiCoFe
d0 = 15 nmT = 800K
Time /ns
Rand. CuNiCoFe alloy has a low GB mobilityand driving force – leading to a low GG rate.Segregation strongly inhibits grain growth.
11/10/2018 | Daniel Utt | [email protected] | 11
Summary
I Lattice distortions in the CuNiCoFe HEA areinfluential at 0 K, but become negligibleabove 50K.
I Monoatomic samples show a perfect GBstructure, localized deviations in the HEA.
I Avg.-atom and random HEA show almostidentical GB mobilities, indicating that thelocal chemical fluctuations do not hinder GBmigration.
I Segregation strongly inhibits grain growth.
‘Compositionally Complex Alloys –High Entropy Alloys’
SPP 2006; STU 611/2-1
11/10/2018 | Daniel Utt | [email protected] | 12
Summary
I Lattice distortions in the CuNiCoFe HEA areinfluential at 0 K, but become negligibleabove 50K.
I Monoatomic samples show a perfect GBstructure, localized deviations in the HEA.
I Avg.-atom and random HEA show almostidentical GB mobilities, indicating that thelocal chemical fluctuations do not hinder GBmigration.
I Segregation strongly inhibits grain growth.
‘Compositionally Complex Alloys –High Entropy Alloys’
SPP 2006; STU 611/2-1
11/10/2018 | Daniel Utt | [email protected] | 12
Summary
I Lattice distortions in the CuNiCoFe HEA areinfluential at 0 K, but become negligibleabove 50K.
I Monoatomic samples show a perfect GBstructure, localized deviations in the HEA.
I Avg.-atom and random HEA show almostidentical GB mobilities, indicating that thelocal chemical fluctuations do not hinder GBmigration.
I Segregation strongly inhibits grain growth.
‘Compositionally Complex Alloys –High Entropy Alloys’
SPP 2006; STU 611/2-1
11/10/2018 | Daniel Utt | [email protected] | 12
Summary
I Lattice distortions in the CuNiCoFe HEA areinfluential at 0 K, but become negligibleabove 50K.
I Monoatomic samples show a perfect GBstructure, localized deviations in the HEA.
I Avg.-atom and random HEA show almostidentical GB mobilities, indicating that thelocal chemical fluctuations do not hinder GBmigration.
I Segregation strongly inhibits grain growth.
‘Compositionally Complex Alloys –High Entropy Alloys’
SPP 2006; STU 611/2-1
11/10/2018 | Daniel Utt | [email protected] | 12
Properties of the avg.-atom
Rand.CuNiCoFe
Avg.Atom
a0 (Å) 3.57 3.57ECoh (eV) –4.14 –4.14C11 (GPa) 172 170C12 (GPa) 124 120C44 (GPa) 101 100α (×10–6 K–1) 21 21TMelt (K) 1550 1425γSF (mJm–2) 28.5 27.0γUSF (Jm–2) 126.9 129.7
11/10/2018 | Daniel Utt | [email protected] | 13
Σ 11 (332) 〈110〉 STGB400K GB Structures
Avg.-atom
Rand.
CuNiCoFe
Seg.
CuNiCoFe
11/10/2018 | Daniel Utt | [email protected] | 14
Σ 11 (332) 〈110〉 STGBPosition
0
20
40Cu
T: 700K to 1000K
T ↑ NiT: 1000K to 1500K
T ↑
0 50 100 1500
20
40Avg.-atomT: 700K to 1400K
T ↑
0 50 100 150 200
Rand. CuNiCoFeT: 700K to 1400K
T ↑
Time /ps
GBtraveldistance/A
11/10/2018 | Daniel Utt | [email protected] | 15
