材料热力学讲义-15

7 major elements and 3 minor elements
Inventors: L. Jiang, J.-C. Zhao, G. Feng
Computational Design of Materials GTD262
Successful ICME example:
• One of the two ICME success examples in a NRC report. • Now widely used in GE gas turbines
TEMPERATU来自百度文库E_CELSIUS

’

Example: Nimonic 263:
Nimonic 263 + MC
Mole Fraction of Ph hases
1100 1000 Temperature, oC 900 800 700 600
No ’
1.0 ’ + ’ 0.9 0.8 0.7
Measured Time to Fail (h)
Measured Time to Fail (h)
Ta: a critical refractory element that is subjected to
high risks of supply and price disruptions
7
7/27/2012
VM
74
7 10-7
NP(*)
76
3 1
72 70
2 2 3
41
0
500 1000 1500 2000 TEMPERATURE_CELSIUS
9
7/27/2012
Thermal Expansion
THERMO-CALC (2011.10.11:13.15) : DATABASE:TCFE5 P=1E5, N=1., W(C)=4E-3; 6 5 FUNC CTION CTE1 10
fcc () Nimonic 263
Solidus 1324oC
Liquidus 1380oC
fcc ()
Liquid
’+ M23C6 ’+ ’-finish
0.6 0.5 0.4 0.3 0.1
’-start
-2 -1 0 1 2 3
-start
4 5
0.2

’
M23C6
7/27/2012
Lecture 15
Examples of Application of Computational Thermodynamics
Why CALPHAD ?
• Phases, mole fractions and compositions • Driving force for nucleation • Scheil simulation for solidification segregation • Thermodynamic quantities • Thermodynamic factor for diffusivity • ……
Al Co 600 700 800 900
Composition, at.%
60
60 50 40 30 20 10 0 400 500 600 700 800 900 Al Co Ti
’
Cr
500
Temperature, oC
Temperature, oC
’:
Calculated ’ So olvus (°C)
Calculation of phase compositions in multicomponent alloys
5
7/27/2012
Example: Nimonic 263
80 70 Ni 80 70 Ni
Composition, at.%
50 40 30 20 10 0 400 Cr Ti

TEMPERATURE_CELSIUS
Molar Volume
Fe-0.4 wt%C
THERMO-CALC (2011.10.11:13.16) : DATABASE:TCFE5 P=1E5, N=1., W(C)=4E-3; 82
80 0.8 78 0.6 0.4 0.2 0 500 1000 1500 2000 TEMPERATURE_CELSIUS 0
TEMPERATURE_CELSIUS

’

3
7/27/2012
Introduction to Ni-based Superalloys
1800 1600 1400 1200 1000 800 600 400 200 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 M OLE_FRACTION AL
4
7/27/2012
Example: Nimonic 263:
1000 Temperature, oC 900 800 700 600
20°C from expt.
Liquid
Nimonic 263 + MC ’+ M23C6 ’-start
’ + ’
No ’
Mole Fraction of f Phases
100 Predicted Time to Fail (h) P
100
Volume fraction included
10
10
1
1
0.1 0.1 1
Regression done using only alloy chemistry 10 100
0.1 0.1 1
Regression done using alloy chemistry and predicted ' volume fraction 10 100
Computational Design of Materials GTD262
Successful ICME example:
4 years from concept to production
GTD222
GTD262
2X creep strength ↑ Ta replacement by Nb: cost ↓ Computational design: validated with only one set of 4 alloys. Now widely used in GE gas turbines
Temperature, ºC
Phase Composition vs. Temperature Diagram
L+Co2Al9 L+Co Al 4 12 fcc(Al) +Co2Al9 1.0 L
Mo ole fraction of Co
0.8 0.6 0.4 0.2 0 200 400 600 800 1000 1200 1400
Mole e Fraction of Phases
0.9 0.8 0.7 0.6 0.5 0.4
fcc () Nimonic 263
Liquidus Solidus S lid o o 1324 C 1380 C
fcc ()
Liquid
Temperature, ºC
MC 0.0 750 919 400 600 800 1000 1200 14001600
957 C
o
0.3 0.2 0.1

’ M23C6
Temperature, oC
Introduction to Ni-based Superalloys
1800 1600 1400 1200 1000 800 600 400 200 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 M OLE_FRACTION AL
1
7/27/2012
Phase Fraction vs. Temperature Diagram
L+Co2Al9 L+Co Al 4 12 fcc(Al) +Co2Al9 1.0 L
Mol le fraction of phases
0.8 0.6 0.4 02 0.2 0 200 400 600 800 1000 1200 1400
2 1 4 4
THERMO-CALC (2011.10.11:13.21) : DATABASE:TCFE5 P=1E5, N=1 P=1E5 N=1., W(C)=4E-3; 3 3 1 13 1.0
4
1:T-273.15,NP(BCC_A2) 2:T-273.15,NP(GRAPHITE) 3:T-273.15,NP(FCC_A1) 4:T-273.15,NP(LIQUID)
1400
Caron & Khan Dharwadkar Henry Sponseller
1300
1200
1100
1000
900 900
1000
1100
1200
1300
1400
Measured ’ Solvus (°C)
• 75 cases tested (51 GE + 24 literature) • Good agreement with measured values: (Stdev = 25 ºC)
Example: Ti-Si
THERMO-CALC (2010.10.03:15.06) : DATABASE:USER X(TI)=0.75, P=1.01325E5, N=1; 45 HEAT CAPACITY Y OF SILICIDES(J/MOL/K)
40
35
30
25
20 -500 0 500 1000 1500 2000 2500
Composition, at.%
Composition, at.%
40 30 20 10 0 900 Mo 1000 1100 Cr 1200 1300
50 40 30 20 10 0 400 Mo Ni 500 600 700 800 Co 900
MC
M23C6
C
Temperature, oC
Temperature, oC
The National Academies Press, Washington, D.C., 2012
8
7/27/2012
Specific heat capacity
H Cp T P
THERMO-CALC (2010.10.03:14.58) : DATABASE:USER P=1.01325E5, N=1; 2400 2200 2000 TEMPERA ATURE_CELSIUS 1800 1600 1400 1200 1000 800 600 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 MOLE_FRACTION SI
Temperature, ºC
2
7/27/2012
Phase Fraction vs. Temperature Diagram
L+Co2Al9 L+Co Al 4 12 fcc(Al) +Co2Al9 1.0 L
1.0
Mole e fraction of phases
0.8 0.6 0.4 0.2 0 200 400 600 800 1000 1200 1400
6
7/27/2012
Volume fractions of phases important
Regression-based prediction of creep strength in Ni-base superalloys Volume fraction not included
Predicted Time to Fail (h)
0.3 0.2 M23C6 0.1 MC 0.0 400 600 800 1000 1200 1400 1600
’
Temperature, oC
Thermodynamics allows prediction of metastability
Example: Nimonic 263
60 50 Ti C 70 60 Cr
1100
1.0
0.9 0.8
fcc ()
’+
’-finish
07 0.7 0.6 0.5 0.4
fcc ()
-phase suspended
Calculation with
-start
2 1 10 -2 10 -1 10 0 10 1 10 2 10 3 10 4 10 5 10 6 Time, hrs
957oC
MC
10 10 10 10 10 10 10 10 10 Time, hrs
6
0.0 750 919 400 600 800 1000 1200 14001600
Temperature, oC Thermo-CalcTM + Ni-database
Nimonic 263: Ni-20Co-20 Cr-6Mo-2 Ti-0.5Al-0.6Fe-0.06C (w/o)