O18-Thermodynamic Calculation on the Stability of …paginas.fe.up.pt/~tofa2010/Apresentacoes_TOFA2010/O18_Thermodyn… · Thermodynamic Calculation on the Stability of ... SINTEF

TOFA2010, Porto, Sep. 12-16, 2010

Thermodynamic Calculation on the Stability of Thermodynamic Calculation on the Stability of Thermodynamic Calculation on the Stability of Thermodynamic Calculation on the Stability of Thermodynamic Calculation on the Stability of Thermodynamic Calculation on the Stability of Thermodynamic Calculation on the Stability of Thermodynamic Calculation on the Stability of

((((((((Fe,MnFe,MnFe,MnFe,MnFe,MnFe,MnFe,MnFe,Mn))))))))33333333AlC Carbide in High Aluminum SteelsAlC Carbide in High Aluminum SteelsAlC Carbide in High Aluminum SteelsAlC Carbide in High Aluminum SteelsAlC Carbide in High Aluminum SteelsAlC Carbide in High Aluminum SteelsAlC Carbide in High Aluminum SteelsAlC Carbide in High Aluminum Steels

Computational Materials Science & Engineering Lab.Computational Materials Science & Engineering Lab.Computational Materials Science & Engineering Lab.Computational Materials Science & Engineering Lab.Computational Materials Science & Engineering Lab.Computational Materials Science & Engineering Lab.Computational Materials Science & Engineering Lab.Computational Materials Science & Engineering Lab.Pohang University of Science & Technology (POSTECH), KoreaPohang University of Science & Technology (POSTECH), KoreaPohang University of Science & Technology (POSTECH), KoreaPohang University of Science & Technology (POSTECH), KoreaPohang University of Science & Technology (POSTECH), KoreaPohang University of Science & Technology (POSTECH), KoreaPohang University of Science & Technology (POSTECH), KoreaPohang University of Science & Technology (POSTECH), Korea

ByeongByeongByeongByeongByeongByeongByeongByeong--------Joo Lee Joo Lee Joo Lee Joo Lee Joo Lee Joo Lee Joo Lee Joo Lee [email protected]@[email protected]@[email protected]@[email protected]@postech.ac.kr

HyukHyukHyukHyukHyukHyukHyukHyuk--------Joong Lee, Jongbae Jeon (POSTECH)Joong Lee, Jongbae Jeon (POSTECH)Joong Lee, Jongbae Jeon (POSTECH)Joong Lee, Jongbae Jeon (POSTECH)Joong Lee, Jongbae Jeon (POSTECH)Joong Lee, Jongbae Jeon (POSTECH)Joong Lee, Jongbae Jeon (POSTECH)Joong Lee, Jongbae Jeon (POSTECH)KwangKwangKwangKwangKwangKwangKwangKwang--------Geun Chin, JaiGeun Chin, JaiGeun Chin, JaiGeun Chin, JaiGeun Chin, JaiGeun Chin, JaiGeun Chin, JaiGeun Chin, Jai--------Hyun Kwak (POSCO)Hyun Kwak (POSCO)Hyun Kwak (POSCO)Hyun Kwak (POSCO)Hyun Kwak (POSCO)Hyun Kwak (POSCO)Hyun Kwak (POSCO)Hyun Kwak (POSCO)

Development of LightDevelopment of LightDevelopment of LightDevelopment of Light----Weight Steels Weight Steels Weight Steels Weight Steels

WhatWhatWhatWhat

Prediction of Phase EquilibriaPrediction of Phase EquilibriaPrediction of Phase EquilibriaPrediction of Phase Equilibria

1st Year (2008) 2nd Year (2009)

Computational Design of High Al SteelsComputational Design of High Al Steels

2 Byeong-Joo Leehttp://cmse.postech.ac.kr

InfraInfraInfraInfra

HowHowHowHow

1 Year (2008)

· Thermodynamic DB · Thermodynamic DB · Thermodynamic DB · Thermodynamic DB (Fe(Fe(Fe(Fe----CCCC----MnMnMnMn----AlAlAlAl-Si-N-P-S))))

2 Year (2009)

· Extension of Thermo. DB· Extension of Thermo. DB· Extension of Thermo. DB· Extension of Thermo. DB· Effect of Solute Al, Fe· Effect of Solute Al, Fe· Effect of Solute Al, Fe· Effect of Solute Al, Fe3333Al, FeAl by Al, FeAl by Al, FeAl by Al, FeAl by

atomistic simulationatomistic simulationatomistic simulationatomistic simulation

· Evaluation of current thermodynamic DB · Evaluation of current thermodynamic DB · Evaluation of current thermodynamic DB · Evaluation of current thermodynamic DB for constituent binary and ternary for constituent binary and ternary for constituent binary and ternary for constituent binary and ternary systemssystemssystemssystems

· · · · FeFeFeFe----CCCC----MnMnMnMn----AlAlAlAl----SiSiSiSi----NNNN----PPPP----SSSS----CrCrCrCr----MoMoMoMo----NiNiNiNi----VVVV----WWWW----TiTiTiTi----NbNbNbNb----BBBB

· Interatomic Potential for Fe· Interatomic Potential for Fe· Interatomic Potential for Fe· Interatomic Potential for Fe----AlAlAlAl

• MotivationMotivationMotivationMotivation

• Background & PurposeBackground & PurposeBackground & PurposeBackground & Purpose

• Thermodynamics AssessmentsThermodynamics AssessmentsThermodynamics AssessmentsThermodynamics Assessments

• ApplicationsApplicationsApplicationsApplications

Contents Contents Contents Contents


• ApplicationsApplicationsApplicationsApplications

• Experimental VerificationExperimental VerificationExperimental VerificationExperimental Verification

• Extension of the Thermodynamics DatabaseExtension of the Thermodynamics DatabaseExtension of the Thermodynamics DatabaseExtension of the Thermodynamics Database

• SummarySummarySummarySummary

MotivationMotivationMotivationMotivation –––– Thermodynamic Calculation vs. ExperimentsThermodynamic Calculation vs. ExperimentsThermodynamic Calculation vs. ExperimentsThermodynamic Calculation vs. ExperimentsD (2Al) 1050℃ quenchedD (2Al) 1050℃ quenchedD (2Al) 1050℃ quenchedD (2Al) 1050℃ quenched

0.1℃/sec0.1℃/sec0.1℃/sec0.1℃/sec1℃/sec1℃/sec1℃/sec1℃/sec

10℃/sec10℃/sec10℃/sec10℃/secPara eq.Para eq.Para eq.Para eq.

Ortho eq.Ortho eq.Ortho eq.Ortho eq.


F (2Al) 1050℃ quenchedF (2Al) 1050℃ quenchedF (2Al) 1050℃ quenchedF (2Al) 1050℃ quenched F (2Al) 1050℃ quenchedF (2Al) 1050℃ quenchedF (2Al) 1050℃ quenchedF (2Al) 1050℃ quenched

5Mn5Mn5Mn5Mn----7Al7Al7Al7Al----0.1C 4Mn0.1C 4Mn0.1C 4Mn0.1C 4Mn----6.6Al6.6Al6.6Al6.6Al----0.2C 3.5Mn0.2C 3.5Mn0.2C 3.5Mn0.2C 3.5Mn----6Al6Al6Al6Al----0.3C 3.5Mn0.3C 3.5Mn0.3C 3.5Mn0.3C 3.5Mn----5.8Al5.8Al5.8Al5.8Al----0.4C 3Mn0.4C 3Mn0.4C 3Mn0.4C 3Mn----4.9Al4.9Al4.9Al4.9Al----0.5C 4Mn0.5C 4Mn0.5C 4Mn0.5C 4Mn----7.3Al7.3Al7.3Al7.3Al----0.3C0.3C0.3C0.3C----0.05Ti0.05Ti0.05Ti0.05Ti

MotivationMotivationMotivationMotivation –––– Microstructure of some candidate SteelsMicrostructure of some candidate SteelsMicrostructure of some candidate SteelsMicrostructure of some candidate Steels


PurposePurposePurposePurpose –––– Provide Thermodynamic Descriptions that can be used Provide Thermodynamic Descriptions that can be used Provide Thermodynamic Descriptions that can be used Provide Thermodynamic Descriptions that can be used for Calculation of Phase Equilibria for Calculation of Phase Equilibria for Calculation of Phase Equilibria for Calculation of Phase Equilibria and Interpretation of Microstructure in High Al Steelsand Interpretation of Microstructure in High Al Steelsand Interpretation of Microstructure in High Al Steelsand Interpretation of Microstructure in High Al Steels

BackgroundBackgroundBackgroundBackground –––– Literature Survey for Thermodynamic AssessmentsLiterature Survey for Thermodynamic AssessmentsLiterature Survey for Thermodynamic AssessmentsLiterature Survey for Thermodynamic Assessments

for Fefor Fefor Fefor Fe----AlAlAlAl----MnMnMnMn----C quaternary systemC quaternary systemC quaternary systemC quaternary system

• FeFeFeFe----C C C C P. Gustafson, Scan. J. Metall. 14 (1985) 259P. Gustafson, Scan. J. Metall. 14 (1985) 259P. Gustafson, Scan. J. Metall. 14 (1985) 259P. Gustafson, Scan. J. Metall. 14 (1985) 259

• AlAlAlAl----C C C C J. Gröbner, H. L. Lukas and F. Aldinger, J. Alloys Compd. 220 (1995) 8.J. Gröbner, H. L. Lukas and F. Aldinger, J. Alloys Compd. 220 (1995) 8.J. Gröbner, H. L. Lukas and F. Aldinger, J. Alloys Compd. 220 (1995) 8.J. Gröbner, H. L. Lukas and F. Aldinger, J. Alloys Compd. 220 (1995) 8.

• MnMnMnMn----C C C C W. Huang, Scand. J. Metall. 19 (1990) 26.W. Huang, Scand. J. Metall. 19 (1990) 26.W. Huang, Scand. J. Metall. 19 (1990) 26.W. Huang, Scand. J. Metall. 19 (1990) 26.

• FeFeFeFe----Al Al Al Al M. Seiersten, SINTEF Report STFM. Seiersten, SINTEF Report STFM. Seiersten, SINTEF Report STFM. Seiersten, SINTEF Report STF----28F93051, Oslo, Norway, 1993.28F93051, Oslo, Norway, 1993.28F93051, Oslo, Norway, 1993.28F93051, Oslo, Norway, 1993.

• FeFeFeFe----Mn Mn Mn Mn W. Huang, CALPHAD 13 (1989) 243.W. Huang, CALPHAD 13 (1989) 243.W. Huang, CALPHAD 13 (1989) 243.W. Huang, CALPHAD 13 (1989) 243.


• FeFeFeFe----Mn Mn Mn Mn W. Huang, CALPHAD 13 (1989) 243.W. Huang, CALPHAD 13 (1989) 243.W. Huang, CALPHAD 13 (1989) 243.W. Huang, CALPHAD 13 (1989) 243.

• AlAlAlAl----Mn Mn Mn Mn A. Jansson, Metall. Trans. A 23A (1992) 2953.A. Jansson, Metall. Trans. A 23A (1992) 2953.A. Jansson, Metall. Trans. A 23A (1992) 2953.A. Jansson, Metall. Trans. A 23A (1992) 2953.

• FeFeFeFe----AlAlAlAl----C C C C D. Connétable, J. Lacaze, P. Maugis, B. Sundman, CALPHAD 32 (2008) 361.D. Connétable, J. Lacaze, P. Maugis, B. Sundman, CALPHAD 32 (2008) 361.D. Connétable, J. Lacaze, P. Maugis, B. Sundman, CALPHAD 32 (2008) 361.D. Connétable, J. Lacaze, P. Maugis, B. Sundman, CALPHAD 32 (2008) 361.

• FeFeFeFe----MnMnMnMn----C C C C W. Huang, Metall. Trans. A 21A (1990) 2115.W. Huang, Metall. Trans. A 21A (1990) 2115.W. Huang, Metall. Trans. A 21A (1990) 2115.W. Huang, Metall. Trans. A 21A (1990) 2115.

• FeFeFeFe----AlAlAlAl----Mn Mn Mn Mn A. Jansson and T.G. Chart, COST 507 Report (1997).A. Jansson and T.G. Chart, COST 507 Report (1997).A. Jansson and T.G. Chart, COST 507 Report (1997).A. Jansson and T.G. Chart, COST 507 Report (1997).

• AlAlAlAl----MnMnMnMn----C C C C ----

M. Seiersten, SINTEF Report No. STF28 F93051, Dept. for Materials Tech., SINTEF SI, Oslo, Norway, 1993.M. Seiersten, SINTEF Report No. STF28 F93051, Dept. for Materials Tech., SINTEF SI, Oslo, Norway, 1993.M. Seiersten, SINTEF Report No. STF28 F93051, Dept. for Materials Tech., SINTEF SI, Oslo, Norway, 1993.M. Seiersten, SINTEF Report No. STF28 F93051, Dept. for Materials Tech., SINTEF SI, Oslo, Norway, 1993.Phase diagram of the FePhase diagram of the FePhase diagram of the FePhase diagram of the Fe----Al system according to the existing steel database, TCFE2000Al system according to the existing steel database, TCFE2000Al system according to the existing steel database, TCFE2000Al system according to the existing steel database, TCFE2000

BackgroundBackgroundBackgroundBackground –––– Literature Survey for FeLiterature Survey for FeLiterature Survey for FeLiterature Survey for Fe----Al Al Al Al


BackgroundBackgroundBackgroundBackground –––– Literature Survey for FeLiterature Survey for FeLiterature Survey for FeLiterature Survey for Fe----AlAlAlAl----MnMnMnMn


BackgroundBackgroundBackgroundBackground –––– Literature Survey for FeLiterature Survey for FeLiterature Survey for FeLiterature Survey for Fe----AlAlAlAl----C C C C

using TCFE2000using TCFE2000using TCFE2000using TCFE2000

Exp data: M. Palm, G. Inden, Intermetallics 3 (1995) 443.



BackgroundBackgroundBackgroundBackground –––– New Assessment of FeNew Assessment of FeNew Assessment of FeNew Assessment of Fe----AlAlAlAl----C C C C


BackgroundBackgroundBackgroundBackground –––– New Assessment of FeNew Assessment of FeNew Assessment of FeNew Assessment of Fe----AlAlAlAl----C C C C

Present Work Present Work Present Work Present Work


κκκκ carbide: Fecarbide: Fecarbide: Fecarbide: Fe3333Al(C,Va) Al(C,Va) Al(C,Va) Al(C,Va)


κκκκ carbide: carbide: carbide: carbide: (Al, Fe)(Al, Fe)(Al, Fe)(Al, Fe)0.250.250.250.25(Al, Fe)(Al, Fe)(Al, Fe)(Al, Fe)0.250.250.250.25(Al, Fe)(Al, Fe)(Al, Fe)(Al, Fe)0.250.250.250.25(Al, Fe)(Al, Fe)(Al, Fe)(Al, Fe)0.250.250.250.25(Va,C)(Va,C)(Va,C)(Va,C)1111

Thermodynamic AssessmentThermodynamic AssessmentThermodynamic AssessmentThermodynamic Assessment –––– FeFeFeFe----AlAlAlAl----Mn with new FeMn with new FeMn with new FeMn with new Fe----Al descriptionAl descriptionAl descriptionAl description


Thermodynamic AssessmentThermodynamic AssessmentThermodynamic AssessmentThermodynamic Assessment –––– AlAlAlAl----MnMnMnMn----C ternary systemC ternary systemC ternary systemC ternary system

700 700 700 700 ooooCCCC 1000 1000 1000 1000 ooooCCCC

κκκκ carbide: Mncarbide: Mncarbide: Mncarbide: Mn3333AlC AlC AlC AlC


Thermodynamic AssessmentThermodynamic AssessmentThermodynamic AssessmentThermodynamic Assessment –––– FeFeFeFe----AlAlAlAl----MnMnMnMn----C quaternary systemC quaternary systemC quaternary systemC quaternary system

κκκκ carbide: (Fe,Mn)carbide: (Fe,Mn)carbide: (Fe,Mn)carbide: (Fe,Mn)3333Al(C,Va) Al(C,Va) Al(C,Va) Al(C,Va)

Exp data: K. Ishida, et al., ISIJ Int. 30 (1990) 680..


Calculated phase relations in FeCalculated phase relations in FeCalculated phase relations in FeCalculated phase relations in Fe----20wt%Mn20wt%Mn20wt%Mn20wt%Mn----AlAlAlAl----C alloys at (a) 900 C alloys at (a) 900 C alloys at (a) 900 C alloys at (a) 900 ooooC and (b) 1200 C and (b) 1200 C and (b) 1200 C and (b) 1200 ooooC.C.C.C.

The effect of Al content on the stability of the κ carbide in The effect of Al content on the stability of the κ carbide in The effect of Al content on the stability of the κ carbide in The effect of Al content on the stability of the κ carbide in FeFeFeFe----30Mn30Mn30Mn30Mn----AlAlAlAl----1C alloys. The solid line represents the phase 1C alloys. The solid line represents the phase 1C alloys. The solid line represents the phase 1C alloys. The solid line represents the phase boundary by the present calculation and the symbols boundary by the present calculation and the symbols boundary by the present calculation and the symbols boundary by the present calculation and the symbols (squares/triangles) represent phase regions with/without (squares/triangles) represent phase regions with/without (squares/triangles) represent phase regions with/without (squares/triangles) represent phase regions with/without κ carbide from experiment.κ carbide from experiment.κ carbide from experiment.κ carbide from experiment.

ApplicationsApplicationsApplicationsApplications –––– Interpretation of microstructure Interpretation of microstructure Interpretation of microstructure Interpretation of microstructure


5Mn-7Al-0.1C 4Mn-6.6Al-0.2C 3.5Mn-6Al-0.3C 3.5Mn-5.8Al-0.4C 3Mn-4.9Al-0.5C 4Mn-7.3Al-0.3C-0.05Ti

Basic strategy : austenite fraction of 0.5 at 1473 KBasic strategy : austenite fraction of 0.5 at 1473 KBasic strategy : austenite fraction of 0.5 at 1473 KBasic strategy : austenite fraction of 0.5 at 1473 K

ApplicationsApplicationsApplicationsApplications –––– Guide for an alloy designGuide for an alloy designGuide for an alloy designGuide for an alloy design


X 1,000X 1,000X 1,000X 1,000

X 10,000X 10,000X 10,000X 10,000

κ

Vacuum Annealingat 650 oCfor 166 hr

Cold-rolled & Annealed0.4C-3.5Mn-5.8Al

Experimental VerificationExperimental VerificationExperimental VerificationExperimental Verification –––– Formation of the Formation of the Formation of the Formation of the κκκκ carbidecarbidecarbidecarbide


AnnealingAnnealingAnnealingAnnealing

PhasePhasePhasePhase Band ContrastBand ContrastBand ContrastBand Contrast

Experimental VerificationExperimental VerificationExperimental VerificationExperimental Verification –––– Formation of the Formation of the Formation of the Formation of the κκκκ carbidecarbidecarbidecarbide


Extension of Thermodynamic DBExtension of Thermodynamic DBExtension of Thermodynamic DBExtension of Thermodynamic DB –––– FeFeFeFe----AlAlAlAl----CrCrCrCr

TCFE2000TCFE2000TCFE2000TCFE2000


FeFeFeFe----AlAlAlAl----Cr 1527℃Cr 1527℃Cr 1527℃Cr 1527℃ FeFeFeFe----AlAlAlAl----Cr 1150℃Cr 1150℃Cr 1150℃Cr 1150℃ FeFeFeFe----AlAlAlAl----Cr 750℃Cr 750℃Cr 750℃Cr 750℃ FeFeFeFe----AlAlAlAl----Cr 600℃Cr 600℃Cr 600℃Cr 600℃

Extension of Thermodynamic DBExtension of Thermodynamic DBExtension of Thermodynamic DBExtension of Thermodynamic DB –––– FeFeFeFe----AlAlAlAl----CrCrCrCr

Present DescriptionPresent DescriptionPresent DescriptionPresent Description


FeFeFeFe----AlAlAlAl----Cr 1527℃Cr 1527℃Cr 1527℃Cr 1527℃ FeFeFeFe----AlAlAlAl----Cr 1150℃Cr 1150℃Cr 1150℃Cr 1150℃ FeFeFeFe----AlAlAlAl----Cr 750℃Cr 750℃Cr 750℃Cr 750℃ FeFeFeFe----AlAlAlAl----Cr 600℃Cr 600℃Cr 600℃Cr 600℃

Extension of Thermodynamic DBExtension of Thermodynamic DBExtension of Thermodynamic DBExtension of Thermodynamic DB –––– FeFeFeFe----AlAlAlAl----NiNiNiNi



FeFeFeFe----AlAlAlAl----Ni 1427℃Ni 1427℃Ni 1427℃Ni 1427℃ FeFeFeFe----AlAlAlAl----Ni 1127℃Ni 1127℃Ni 1127℃Ni 1127℃ FeFeFeFe----AlAlAlAl----Ni 1000℃Ni 1000℃Ni 1000℃Ni 1000℃ FeFeFeFe----AlAlAlAl----Ni 700℃Ni 700℃Ni 700℃Ni 700℃

Extension of Thermodynamic DBExtension of Thermodynamic DBExtension of Thermodynamic DBExtension of Thermodynamic DB –––– FeFeFeFe----AlAlAlAl----NiNiNiNi



FeFeFeFe----AlAlAlAl----Ni 1427℃Ni 1427℃Ni 1427℃Ni 1427℃ FeFeFeFe----AlAlAlAl----Ni 1127℃Ni 1127℃Ni 1127℃Ni 1127℃ FeFeFeFe----AlAlAlAl----Ni 1000℃Ni 1000℃Ni 1000℃Ni 1000℃ FeFeFeFe----AlAlAlAl----Ni 700℃Ni 700℃Ni 700℃Ni 700℃

Extension of Thermodynamic DBExtension of Thermodynamic DBExtension of Thermodynamic DBExtension of Thermodynamic DB –––– FeFeFeFe----AlAlAlAl----NbNbNbNb



FeFeFeFe----AlAlAlAl----Nb 1000℃Nb 1000℃Nb 1000℃Nb 1000℃ FeFeFeFe----AlAlAlAl----Nb 800℃Nb 800℃Nb 800℃Nb 800℃FeFeFeFe----AlAlAlAl----Nb 1250℃Nb 1250℃Nb 1250℃Nb 1250℃ FeFeFeFe----AlAlAlAl----Nb 1050℃Nb 1050℃Nb 1050℃Nb 1050℃

Extension of Thermodynamic DBExtension of Thermodynamic DBExtension of Thermodynamic DBExtension of Thermodynamic DB –––– FeFeFeFe----AlAlAlAl----NbNbNbNb



FeFeFeFe----AlAlAlAl----Nb 1000℃Nb 1000℃Nb 1000℃Nb 1000℃ FeFeFeFe----AlAlAlAl----Nb 800℃Nb 800℃Nb 800℃Nb 800℃FeFeFeFe----AlAlAlAl----Nb 1250℃Nb 1250℃Nb 1250℃Nb 1250℃ FeFeFeFe----AlAlAlAl----Nb 1050℃Nb 1050℃Nb 1050℃Nb 1050℃

Extension of Thermodynamic DBExtension of Thermodynamic DBExtension of Thermodynamic DBExtension of Thermodynamic DB –––– FeFeFeFe----AlAlAlAl----TiTiTiTi



FeFeFeFe----AlAlAlAl----Ti 1250℃Ti 1250℃Ti 1250℃Ti 1250℃ FeFeFeFe----AlAlAlAl----Ti 1050℃Ti 1050℃Ti 1050℃Ti 1050℃ FeFeFeFe----AlAlAlAl----Ti 1000℃Ti 1000℃Ti 1000℃Ti 1000℃ FeFeFeFe----AlAlAlAl----Ti 800℃Ti 800℃Ti 800℃Ti 800℃

Extension of Thermodynamic DBExtension of Thermodynamic DBExtension of Thermodynamic DBExtension of Thermodynamic DB –––– FeFeFeFe----AlAlAlAl----TiTiTiTi



FeFeFeFe----AlAlAlAl----Ti 1250℃Ti 1250℃Ti 1250℃Ti 1250℃ FeFeFeFe----AlAlAlAl----Ti 1050℃Ti 1050℃Ti 1050℃Ti 1050℃ FeFeFeFe----AlAlAlAl----Ti 1000℃Ti 1000℃Ti 1000℃Ti 1000℃ FeFeFeFe----AlAlAlAl----Ti 800℃Ti 800℃Ti 800℃Ti 800℃

Ti: an element that may have effect on the stability of the Kappa carbide Ti: an element that may have effect on the stability of the Kappa carbide Ti: an element that may have effect on the stability of the Kappa carbide Ti: an element that may have effect on the stability of the Kappa carbide

Extension of Thermodynamic DBExtension of Thermodynamic DBExtension of Thermodynamic DBExtension of Thermodynamic DB –––– AlAlAlAl----TiTiTiTi----CCCC


• Alloy design to reduce the ordering tendency.Alloy design to reduce the ordering tendency.Alloy design to reduce the ordering tendency.Alloy design to reduce the ordering tendency.

• Why B2/D0Why B2/D0Why B2/D0Why B2/D03333 ordering occurs in Feordering occurs in Feordering occurs in Feordering occurs in Fe----Al, FeAl, FeAl, FeAl, Fe----Si systems?Si systems?Si systems?Si systems?

• Prediction of ordering tendency without firstPrediction of ordering tendency without firstPrediction of ordering tendency without firstPrediction of ordering tendency without first----principles calculation?principles calculation?principles calculation?principles calculation?

Special Issue Special Issue Special Issue Special Issue –––– How to avoid B2/D0How to avoid B2/D0How to avoid B2/D0How to avoid B2/D03333 ordering?ordering?ordering?ordering?


Compare Interaction Parameters Compare Interaction Parameters Compare Interaction Parameters Compare Interaction Parameters

of BCC solid solution phase of BCC solid solution phase of BCC solid solution phase of BCC solid solution phase

in Fein Fein Fein Fe----X / AlX / AlX / AlX / Al----X binary systemsX binary systemsX binary systemsX binary systems

Why B2/D0Why B2/D0Why B2/D0Why B2/D03333 ordering in Feordering in Feordering in Feordering in Fe----Al & FeAl & FeAl & FeAl & Fe----Si systems? Si systems? Si systems? Si systems?


Interaction parameter L0 of BCC (or FCC if BCC doesn’t exist) FeInteraction parameter L0 of BCC (or FCC if BCC doesn’t exist) FeInteraction parameter L0 of BCC (or FCC if BCC doesn’t exist) FeInteraction parameter L0 of BCC (or FCC if BCC doesn’t exist) Fe----M and AlM and AlM and AlM and Al----M alloysM alloysM alloysM alloys

• Thermodynamic description for the FeThermodynamic description for the FeThermodynamic description for the FeThermodynamic description for the Fe----MnMnMnMn----AlAlAlAl----C system C system C system C system that can be used for calculation of phase equilibria that can be used for calculation of phase equilibria that can be used for calculation of phase equilibria that can be used for calculation of phase equilibria among among among among bcc, fcc, (Fe,Mn)bcc, fcc, (Fe,Mn)bcc, fcc, (Fe,Mn)bcc, fcc, (Fe,Mn)3333AlC AlC AlC AlC carbide is now availablecarbide is now availablecarbide is now availablecarbide is now availablefor disordered regionfor disordered regionfor disordered regionfor disordered region....

ConclusionConclusionConclusionConclusionThermodynamic Calculation on the Stability of (Thermodynamic Calculation on the Stability of (Thermodynamic Calculation on the Stability of (Thermodynamic Calculation on the Stability of (Thermodynamic Calculation on the Stability of (Thermodynamic Calculation on the Stability of (Thermodynamic Calculation on the Stability of (Thermodynamic Calculation on the Stability of (Fe,MnFe,MnFe,MnFe,MnFe,MnFe,MnFe,MnFe,Mn))))))))33333333AlC Carbide in High Aluminum SteelsAlC Carbide in High Aluminum SteelsAlC Carbide in High Aluminum SteelsAlC Carbide in High Aluminum SteelsAlC Carbide in High Aluminum SteelsAlC Carbide in High Aluminum SteelsAlC Carbide in High Aluminum SteelsAlC Carbide in High Aluminum Steels


• An extension to An extension to An extension to An extension to FeFeFeFe----CCCC----MnMnMnMn----AlAlAlAl----SiSiSiSi----NNNN----PPPP----SSSS----CrCrCrCr----MoMoMoMo----NiNiNiNi----VVVV----WWWW----TiTiTiTi----NbNbNbNb----B system was made (B system was made (B system was made (B system was made (for for for for FeFeFeFe----rich regionrich regionrich regionrich region).).).).

• A scheme for alloy design of high Al steels is proposedA scheme for alloy design of high Al steels is proposedA scheme for alloy design of high Al steels is proposedA scheme for alloy design of high Al steels is proposedpaying attention to the paying attention to the paying attention to the paying attention to the austeniteausteniteausteniteaustenite/ferrite transformation /ferrite transformation /ferrite transformation /ferrite transformation and and and and orderingorderingorderingordering....

Property MEAM-Al (exp.) MEAM-Fe (exp.)C11 (1012 dyne/cm2)C12 (1012 dyne/cm2)C44 (1012 dyne/cm2)

Evf (eV)

QD (eV)EI

f (eV)

1.143 (1.143)0.619 (0.619)0.316 (0.316)0.68 (0.68)1.33 (1.33)

2.49 (-)

2.430 (2.431)1.380 (1.381)1.219 (1.219)1.75 (1.79)2.28 (2.5)4.20 (-)

E(100) (mJ/m2)E(110) (mJ/m2)E (mJ/m2)

848 (1085a)948 (1085a)629 (1085a)

2510 (2360a)2356 (2360a)2668 (2360a)

Interatomic Potential Interatomic Potential Interatomic Potential Interatomic Potential –––– pure Fe and Al pure Fe and Al pure Fe and Al pure Fe and Al [PRB 64, 184102 (2001); 68, 144112 (2003)]


E(111) (mJ/m2)d(100) (%)d(110) (%)d(111) (%)

629 (1085a)+1.8 (+1.8)

-8.9 (-8.5±1.0)+1.0 (0.9±0.5)

2668 (2360a)-1.1 (-0.2, -1.5)

-1.5 (0) -10.5 (-16.9)

Ebcc/fcc (eV/atom)Efcc/hcp(eV/atom)

0.12 (0.10b)0.03 (0.06b)

0.048 (0.082b)-0.018 (-0.023b)

(0-100oC) (10-6/K)Cp (0-100oC) (J/mol·K)

m.p. (K)Hm (KJ/mol)

Vm (%)

22.0 (23.5)26.2 (24.7)937 (933)11.0 (10.7)6.7 (6.5)

12.4 (12.1)26.1 (25.5)2000 (1811)13.2 (13.8)4.0 (3.5)∆

∆

∆

∆∆

ε

∆

∆

Interatomic Potential Interatomic Potential Interatomic Potential Interatomic Potential –––– FeFeFeFe----Al binaryAl binaryAl binaryAl binary [JPCM 22, 175702 (2010)]


Brief review on the possible crystal structures in Fe-Al binary system

� B2 structure (FeAl)

Dislocation Statics in FeDislocation Statics in FeDislocation Statics in FeDislocation Statics in Fe----Al binary alloysAl binary alloysAl binary alloysAl binary alloys


Purpose� To understand dislocation structures of Fe-Al system in atomic level� To obtain the dependency of stress-strain responses on crystal structures

2

� D03 structure (Fe3Al)� Random solid solutions

APBAPBAPBAPB

Edge Dislocation Structure Edge Dislocation Structure Edge Dislocation Structure Edge Dislocation Structure –––– B2 structureB2 structureB2 structureB2 structure


Super dislocations in B2 structure (FeAl) � Dissociated into two super partial dislocations connected by

anti-phase boundary

NN APBNN APBNN APBNN APB NN APBNN APBNN APBNN APB2NN APB2NN APB2NN APB2NN APB

Edge Dislocation Structure Edge Dislocation Structure Edge Dislocation Structure Edge Dislocation Structure –––– D0D0D0D03333 structurestructurestructurestructure


NN APBNN APBNN APBNN APB NN APBNN APBNN APBNN APB2NN APB2NN APB2NN APB2NN APB

Super dislocations in D03 structure � Dissociated into four super partial dislocations connected by anti-

phase boundary� Two types of APBs : nearest neighbor (NN) and second NN

02020202Edge Dislocation Structure Edge Dislocation Structure Edge Dislocation Structure Edge Dislocation Structure –––– Random solid solutionsRandom solid solutionsRandom solid solutionsRandom solid solutions


Fe3Al random alloy� Perfect edge dislocation

FeAl random alloy� Thermodynamically unstable

phase� Hard to define dislocation (due

to the high distortion )

StressStressStressStress----Strain Response Strain Response Strain Response Strain Response –––– Experimental SetupExperimental SetupExperimental SetupExperimental Setup

� 25x12.4x7.1 nm3 (172000 atoms)

� 2NN MEAM (Fe-Al) � 0K statics� Strain controlled deformation

systemRc = 4.0


ττττ� Rc = 4.0� PBC along dislocation glide

and line direction

Dislocation “inside” Fe-Al intermetallics

Same composition (Fe3Al)

Same composition (FeAl)

StressStressStressStress----Strain Response Strain Response Strain Response Strain Response –––– 0 K statics simulation 0 K statics simulation 0 K statics simulation 0 K statics simulation


� Strengthening effect : D03(highest), RandomStrengthening effect : D03(highest), RandomStrengthening effect : D03(highest), RandomStrengthening effect : D03(highest), Random----FeAl(lowest)FeAl(lowest)FeAl(lowest)FeAl(lowest)� Ordered phase : harder than random alloy (same composition)Ordered phase : harder than random alloy (same composition)Ordered phase : harder than random alloy (same composition)Ordered phase : harder than random alloy (same composition)� Anti phase boundary hardeningAnti phase boundary hardeningAnti phase boundary hardeningAnti phase boundary hardening

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.00

100

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300

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500

stre

ss (

MP

a)

strain (%)

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