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$: rsf AC ThermDatabase PDF - RWTH Aachen Universityweb.access.rwth-aachen.de/THERMOCALC/proceedings/...Calculated by [93Dup] 500 1500 2500 3500 0 0.2 0.4 0.6 0.8 1 Mol. fracn. Ta Temp.$
Thermodynamische Datenbanken

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1

R. Schmid-Fetzer

Contributions byJ. Klingbeil, H. Cordes, F. Goesmann, K. Zeng, K. Bhanumurthy, A. Pisch, R. Wenzel, G. Fischer,

D. Kevorkov, J. Gröbner, T. Studnitzky, B. Onderka, S.M. Schnurre, D. Mirkovic, I. Chumak

supported by the German Research Council (DFG), Volkswagenstiftung,Federal Ministry of Education & Research (BMBF), European Union (EU)


Outline2

Thermodynamic databasesExample: Mg alloy databaseTernary parametersKey experimentsQuality problems with binary systems / software

ApplicationsDeveloping creep resistant Mg alloysSolderingAl-alloy solidification, microsegregation


Mg database: Binary systems3

Ag-Al Ag-Ca Ag-Ce Ag-Cu Ag-Gd Ag-Li Ag-Mg Ag-Mn Ag-Nd Ag-Sc Ag-Si Ag-Sr Ag-Y Ag-Zn Ag-ZrAl-Ca Al-Ce Al-Cu Al-Gd Al-Li Al-Mg Al-Mn Al-Nd Al-Sc Al-Si Al-Sr Al-Y Al-Zn Al-ZrCa-Ce Ca-Cu Ca-Gd Ca-Li Ca-Mg Ca-Mn Ca-Nd Ca-Sc Ca-Si Ca-Sr Ca-Y Ca-Zn Ca-ZrCe-Cu Ce-Gd Ce-Li Ce-Mg Ce-Mn Ce-Nd Ce-Sc Ce-Si Ce-Sr Ce-Y Ce-Zn Ce-ZrCu-Gd Cu-Li Cu-Mg Cu-Mn Cu-Nd Cu-Sc Cu-Si Cu-Sr Cu-Y Cu-Zn Cu-ZrGd-Li Gd-Mg Gd-Mn Gd-Nd Gd-Sc Gd-Si Gd-Sr Gd-Y Gd-Zn Gd-ZrLi-Mg Li-Mn Li-Nd Li-Sc Li-Si Li-Sr Li-Y Li-Zn Li-ZrMg-Mn Mg-Nd Mg-Sc Mg-Si Mg-Sr Mg-Y Mg-Zn Mg-ZrMn-Nd Mn-Sc Mn-Si Mn-Sr Mn-Y Mn-Zn Mn-ZrNd-Sc Nd-Si Nd-Sr Nd-Y Nd-Zn Nd-ZrSc-Si Sc-Sr Sc-Y Sc-Zn Sc-ZrSi-Sr Si-Y Si-Zn Si-ZrSr-Y Sr-Zn Sr-ZrY-Zn Y-ZrZn-Zr 16 components:

120 binary systems

41 from literature + checked + adapted37 own modeling + experiments42 missing systems

120216

=⎟⎟⎠

⎞⎜⎜⎝

⎛


Mg database: Ternary systems4

Al-Ca-Li Al-Ca-Si Al-Ce-Si Al-Ca-MgAl-Ca-Si Al-Ce-Mg Al-Cu-Li Al-Cu-Mg Al-Cu-Nd

Al-Cu-Si Al-Cu-Zn Al-Gd-Mg Al-Li-Mg Al-Li-Mn Al-Li-Si Al-Mg-Mn Al-Mg-Sc Al-Mg-Si Al-Mg-Y Al-Mg-Zn Al-Mn-Sc

Al-Mn-Si Al-Si-Y Al-Si-Zn Ca-Li-Mg Ca-Li-Si Ca-Mg-Si Ce-Li-MgCe-Mg-Mn Ce-Mg-Sc Ce-Mn-Sc Cu-Li-Mg Cu-Mg-Si Cu-Mg-Y

Cu-Mg-Zn Gd-Li-Mg Gd-Mg-Mn Gd-Mg-Sc Gd-Mn-Sc Li-Mg-Si Li-Mg-Zn Mg-Mn-Sc Mg-Mn-Y Mg-Mn-Zr Mg-Y-Zr Mn-Sc-Y Mn-Y-Zr

Exper.+Modell. Literature&Check Plausibility-Check

Ag-Al Ag-Ca Ag-Ce Ag-Cu Ag-Gd Ag-Li Ag-Mg Ag-Mn Ag-Nd Ag-Sc Ag-Si Ag-Sr Ag-Y Ag-Zn Ag-ZrAl-Ca Al-Ce Al-Cu Al-Gd Al-Li Al-Mg Al-Mn Al-Nd Al-Sc Al-Si Al-Sr Al-Y Al-Zn Al-ZrCa-Ce Ca-Cu Ca-Gd Ca-Li Ca-Mg Ca-Mn Ca-Nd Ca-Sc Ca-Si Ca-Sr Ca-Y Ca-Zn Ca-ZrCe-Cu Ce-Gd Ce-Li Ce-Mg Ce-Mn Ce-Nd Ce-Sc Ce-Si Ce-Sr Ce-Y Ce-Zn Ce-ZrCu-Gd Cu-Li Cu-Mg Cu-Mn Cu-Nd Cu-Sc Cu-Si Cu-Sr Cu-Y Cu-Zn Cu-ZrGd-Li Gd-Mg Gd-Mn Gd-Nd Gd-Sc Gd-Si Gd-Sr Gd-Y Gd-Zn Gd-ZrLi-Mg Li-Mn Li-Nd Li-Sc Li-Si Li-Sr Li-Y Li-Zn Li-ZrMg-Mn Mg-Nd Mg-Sc Mg-Si Mg-Sr Mg-Y Mg-Zn Mg-ZrMn-Nd Mn-Sc Mn-Si Mn-Sr Mn-Y Mn-Zn Mn-ZrNd-Sc Nd-Si Nd-Sr Nd-Y Nd-Zn Nd-ZrSc-Si Sc-Sr Sc-Y Sc-Zn Sc-ZrSi-Sr Si-Y Si-Zn Si-ZrSr-Y Sr-Zn Sr-ZrY-Zn Y-ZrZn-Zr

possible ternaries

560316

=⎟⎟⎠

⎞⎜⎜⎝

⎛


Mg database: multicomponent systems5

Ag-Al Ag-Ca Ag-Ce Ag-Cu Ag-Gd Ag-Li Ag-Mg Ag-Mn Ag-Nd Ag-Sc Ag-Si Ag-Sr Ag-Y Ag-Zn Ag-ZrAl-Ca Al-Ce Al-Cu Al-Gd Al-Li Al-Mg Al-Mn Al-Nd Al-Sc Al-Si Al-Sr Al-Y Al-Zn Al-ZrCa-Ce Ca-Cu Ca-Gd Ca-Li Ca-Mg Ca-Mn Ca-Nd Ca-Sc Ca-Si Ca-Sr Ca-Y Ca-Zn Ca-ZrCe-Cu Ce-Gd Ce-Li Ce-Mg Ce-Mn Ce-Nd Ce-Sc Ce-Si Ce-Sr Ce-Y Ce-Zn Ce-ZrCu-Gd Cu-Li Cu-Mg Cu-Mn Cu-Nd Cu-Sc Cu-Si Cu-Sr Cu-Y Cu-Zn Cu-ZrGd-Li Gd-Mg Gd-Mn Gd-Nd Gd-Sc Gd-Si Gd-Sr Gd-Y Gd-Zn Gd-ZrLi-Mg Li-Mn Li-Nd Li-Sc Li-Si Li-Sr Li-Y Li-Zn Li-ZrMg-Mn Mg-Nd Mg-Sc Mg-Si Mg-Sr Mg-Y Mg-Zn Mg-ZrMn-Nd Mn-Sc Mn-Si Mn-Sr Mn-Y Mn-Zn Mn-ZrNd-Sc Nd-Si Nd-Sr Nd-Y Nd-Zn Nd-ZrSc-Si Sc-Sr Sc-Y Sc-Zn Sc-ZrSi-Sr Si-Y Si-Zn Si-ZrSr-Y Sr-Zn Sr-ZrY-Zn Y-ZrZn-Zr

multi-component

MgMg

Mg

Si

Al

Li

RE

Ca

Si

Al


Building of multicomponent systems6

Gibbs energy dataSystem

• ExtrapolationQuaternary& higher

• Ternary solid phases?• Extrapolation for solution phases,careful with ternary parameters

Ternary

• Thorough assessment neededBinary

• SGTE data, 1991 DinsdaleUnary


Key experiments7

Sample selection• Calculated important reactions

Sample preparation• Levitation Melting• Arc Melting• Electron Beam Melting• Reaction Sintering

Sample analysis• Calorimetry (Calvet-DSC, drop)• Thermal Analysis (DTA, STA)• X-ray Diffractometry (XRD, 25-1500°C)• Electron Microscopy (SEM/EDX/WDX)• Metallography, Optical Microscopy

Alloysample

Ta capsule

Calorimetry

500 600 700 800-2.0

-1.5

-1.0

-0.5

0.0

0.5

1.0

1.5

primaryeutectic

Hea

t flo

w in

W/g

Temperature in °C

5

2 4 6 8400

600

800

1000

1200

Al 90Ce 0Si 10

Al 90Ce 10Si 0

U11

E1

E2

τ1 + (Al)

τ1 + τ2 + (Al)

L + τ2 + (Al)

L + (Al)

Al11Ce3 (l)+ τ1 + (Al) τ2 + (Al) + (Si)

L + τ1 +Al11Ce3(l)

L + Al11Ce3(l)

L + τ1

cooling; strong peak heating; strong peak cooling; weak peak heating; weak peak

Tem

pera

ture

, °C

Si, at.%

wwwwww.imet.tu.imet.tu--clausthalclausthal.de.de

Al-Ce-Si8


Thermodynamic calculation confirms:

τ1 primary, τ2 peritectic formation (transition reaction)Al90 at.% Al

Si

Ce

τ1τ2(Al)

As-cast, 870 h at 570°C

20 40 60

400

600

800

1000

1200

1400

1600

Al 80Ce 20Si 0

Al 0Ce 20Si 80

U6

U11

P2 653°C

E2 573°C E1

L + (Si) + τ2

(Si) + τ2+ τ1

(Al) + (Si) + τ2

(Al) + τ2+ τ1

(Al) + Al11Ce3(l)+ τ1

L + Al11Ce3(h)

L + Al11Ce3(l)+ τ1

L + τ1L + (Si)+ τ1

L

cooling; strong peak heating; strong peak cooling; weak peak heating; weak peak

Tem

pera

ture

, °C

Al, at.%

20 at.% Ce constant9

wwwwww.imet.tu.imet.tu--clausthalclausthal.de/.de/agrsfagrsfAl

20 at.% Ce

Si

Ce

Sample 9

9


Impact of ternary parameters10

Hg

Bi Sn

extrapolated from binaries,

no ternary parameter, L=0

Binary excess Gibbs energy:EGbin = L xA xB


Impact of ternary parameters11

Ternary excess Gibbs energy:EGtern = L xA xB xC

aC = xC along the section xC = 0.5Because RT ln γC = L xA xB (1-2 xC)

Careful with ternary L-parameters ! Fitting tool for phase diagrams? - Check impact on activities !

Problems using first-generation software12

wwwwww..computhermcomputherm..comcom wwwwww.imet.tu.imet.tu--clausthalclausthal.de.de

• Software does not always find stable phase equilibria

• User may not know all the initial values

• Phase diagrams differ for given thermodynamic description

Reliability problem:

Global Gibbs energy minimum not found automatically

wwwwww..computhermcomputherm..comcom wwwwww.imet.tu.imet.tu--clausthalclausthal.de /.de /agrsfagrsf

Y. Austin Chang, Shuanglin Chen, Fan Zhang, Xinyan Yan, Fanyou Xie , Rainer Schmid-Fetzer, W. Alan Oates: Progr. Mater. Science, 49 (2004) 313-345



Software problem

Assessment problem1. Inverted miscibility gap

2. Low-T phases stable again at high-T

3. Ordered phases overlooked

Calculated constrained phase diagrams (e.g. metastable Fcc) often do not make sense.

Published assessments contain errors


Inverted miscibility gap: Si-Ta14


Calculated by [89Vah]Si Ta

Error detected by Pandat


More examples:Co-Mo [99Dav], Si-W [89Vah], Al-Mo [97Sau], Al-W [98Ans], Al-N [98Ans], Fe-Si [98Ans], Sn-Zr [98Ans], Sn-Ti [98Ans]: Temp < 3000 K in most of these cases.

Sn-Zr

Low-T phases stable again at High-T: Co-Si15


More examples:Nb-C [97Hua], Mo-C[88Ans], Fe-C [85Gus], Ni-C [87Gab], Al-Co [98Dup], Cr-Ta [93Cup], Ni-Ti [96Bel].

Calculated diagram by [92Cho] Error detected by Pandat


Error detected by Pandat

Ordered phases overlooked: Al-Nb16


Other example: Fe-Ta [93Coe]

Calculated diagram by [98Ans]


Terminal solution reappears: Mg-Sn17


Calculated diagram [1993Frie]J. Chim. Phys. (1993) 90, 181-187

wwwwww.imet.tu.imet.tu--clausthalclausthal.de /.de /agrsfagrsf

Error detected by PandatT[

C]

X[SN]

0

100

200

300

400

500

600

700

800

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0SNMG

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 10

100

200

300

400

500

600

700

800

X[SN]

T[C

]

hcp

Mg Sn

L

hcp

hcp : regular solution

L°Mg,Sn= - 43007.6 - 4.05666*T;

L-parameter is too negative.

hcp

L

Mg Sn

Calculated by [93Dup]

500

1500

2500

3500

0 0.2 0.4 0.6 0.8 1

Mol. fracn. Ta

Tem

p. /

K

Liquid

Bcc BccCr2Ta_HT

Cr2Ta_LT

Constrained Phase diagram:Metastable diagram (no Liquid)calculated by Pandat using the same parameters of [93Dup]

500

1500

2500

3500

0 0.2 0.4 0.6 0.8 1

Mol. fracn. Ta

Tem

p. /

K

Cr2Ta_LT

Cr2Ta_LT

Cr2

Ta_H

T

Bcc

Bcc

Improbable Constrained Phase Diagram: Cr-Ta18


Ordered LT stable at high T


500

1500

2500

3500

0 0.2 0.4 0.6 0.8 1

Mol. fracn. Ta

Tem

p. /

K

Liquid

Cr2Ta_HT

Cr2Ta_LT

BccBcc

Constrained Phase Diagram: Cr-Ta19


Calculated by [2001Zha]

Improved modeling: C15 (LT) & C14 (HT) phases using

Cluster Site Approximation (CSA) with fewer parameters [2001Zha]

Metstable diagram (no Liquid)calculated by [2001Zha]

500

1500

2500

3500

0 0.2 0.4 0.6 0.8 1Mol. fracn. Ta

Tem

p. /

K

Bcc

Cr2Ta_HT

Cr2Ta_LT

[2001Zha] F. Zhang, S.-L. Chen, Y. A. Chang and W. A. Oates, “An Improved Approach for Obtaining Thermodynamic Descriptions of Intermetallic Phases: Application to the Cr-Ta System”, Intermetallics, 2001, 9, 1079-1083.




These mistakes have been made when the desired answers are known (the experimental binary phase diagrams).

How can we rely on calculations carried out this way when the answer is not known(multicomponent phase diagrams)?

351 binaries

2925 ternaries

17550 quaternaries….

Example:

27 elements

(COST database)


Second-generation: Pandat21


No user knowledge on demixing or ordering required.

No initial values required.

Finds automatically the correct phase diagram given a thermodynamic description.


T[C]

X[ZN]

0

100

200

300

400

500

600

700

800

900

1000

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8

Al-Mg-Cu-Zn-Mn-Si with xMg = xCu = xMn = xSi = 0.0522


L

L+β-AlMnSi

L+Mn11Si19

fcc1+fcc2+(Si)+σ+τ+Al4Mn

L+β-AlMnSi+δ-AlMnSi



Outline23

Calphad method

Thermodynamic databasesExample: Mg alloy databaseTernary parametersKey experimentsQuality problems with binary systems

ApplicationsDeveloping creep resistant Mg alloysSolderingAl-alloy solidification, microsegregation

ADAMIS24

Elements: Ag, Bi, Cu, In, Sb, Sn, Zn, Pb

Thermodynamic Assessment

Surface tension and viscosity

Alloy Database for Micro-Solders

X. J. Liu, I. Ohnuma, R.Kainuma, K. Ishida: Tohoku University, Japan

S. L. Chen and Y. A. Chang: CompuTherm & University of Wisconsin, USA

wwwwww..computhermcomputherm..comcom wwwwww.i.i--sciencescience..coco..jpjp wwwwww.imet.tu.imet.tu--clausthalclausthal.de/.de/agrsfagrsf

ADAMIS - - - - - - - - - - PandatPanEngine

25

Phase diagram calculation

Liquidus projection ($ 3 components)

Solidification simulationScheil, equilibrium

Surface tension and viscosity calculation(ternary contours)


Surface Tension and Viscosityat Constant Composition

26

Sn-X Candidate Solders (mostly eutectic composition)

Surface Tension Viscosity


Viscosity Contour27

Liquid Sn-Sb-BiAlloys at 900 K

X[SB]

X[BI]

0.0

0.2

0.3

0.5

0.7

0.9

0.0 0.2 0.4 0.6 0.8 1.00 0.2 0.4 0.6 0.8 10

0.2

0.4

0.6

0.8

1

X[BI]

X[SB

]

0.85mPas

0.9

0.95

1.0

1.051.11.151.21.251.3

Sb

BiSn

0.951.0

0.9

0.85mPas

0.9

0.95

1.0

1.051.11.151.21.251.3

Sb

BiSn

0.951.0

0.9

0.85mPas

0.9

0.95

1.0

1.051.11.151.21.251.3

Sb

BiSn

0.951.0

0.9

0.85mPas

0.9

0.95

1.0

1.051.11.151.21.251.3

Sb

BiSn

0.951.0

0.9

0.85mPas

0.9

0.95

1.0

1.051.11.151.21.251.3

Sb

BiSn

0.951.0

0.9

0.85mPas

0.9

0.95

1.0

1.051.11.151.21.251.3

Sb

BiSn

0.951.0

0.9

0.85mPas

0.9

0.95

1.0

1.051.11.151.21.251.3

Sb

BiSn

0.951.0

0.9

0.85mPas

0.9

0.95

1.0

1.051.11.151.21.251.3

Sb

BiSn

0.951.0

0.9

0.85mPas

0.9

0.95

1.0

1.051.11.151.21.251.3

Sb

BiSn

0.951.0

0.9

0.85mPas

0.9

0.95

1.0

1.051.11.151.21.251.3

Sb

BiSn

0.951.0

0.9

0.85mPas

0.9

0.95

1.0

1.051.11.151.21.251.3

Sb

BiSn

0.951.0

0.9


Surface Tension and Viscosity Contours28

Liquid Sn-Cu-Ag alloys at 1000 °C

X[CU]

X[AG]

0.00

0.09

0.17

0.26

0.35

0.43

0.52

0.61

0.69

0.78

0.87

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.00 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 10

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

X[AG]

X[CU

]

0.8

1.0

1.21.4

1.6

Sn Ag

Cu

X[CU]

X[AG]

0.00

0.09

0.17

0.26

0.35

0.43

0.52

0.61

0.69

0.78

0.87

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.00 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 10

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

X[AG]

X[CU

]

550

600650

700750

800850

900950

1000

1050

1100

Sn Ag

Cu

550

600650

700750

800850

900950

1000

1050

1100

Sn Ag

Cu

550

600650

700750

800850

900950

1000

1050

1100

Sn Ag

Cu

Surface Tension Viscosity

mN/m mPa.s


Surface Tension σ29

J. A. V. Butler, Proc. Roy. Soc.A, A135 (1935) 348-375

K. S. Yeum, R. Speiser and D. R. Poirier, Metall. Trans.B, 20B(1989) 693-703

T. Tanaka and I. Iida, Steel Research, 65 (1994)p. 21.

Extrapolation by knowledge of excess Gibbs energy Gxs

b = 1.091 for close-packed lattice

β = 0.83 for liquid metalsxsi

xsi GG β=*

3/23/1ii VbNS =

Partial excess Gibbs energies:

σi surface tension of pure liquid (i),

Si molar surface area in a monolayer of pure liquid (i)

ai activity of (i) in bulk alloy

ai* activity of (i) in "surface phase * " i

i

ii a

aSRT *

ln+=σσ

i = 1…c components

11

* =∑=

c

iix

( i = 1...c )

Solve these c+1 equations for the c+1 unknowns σ and xi*

( )),(),(1ln **

ixs

iixs

iii

i

ii xTGxTG

Sxx

SRT

−++= βσσ


Viscosity η30

H. Eyring, J. Chem. Phys., 4 (1936) 283-291

S. Seetharaman and D. Sichen, Metall. Mater. Trans. B, 25B (1993) 589-595

⎟⎟⎠

⎞⎜⎜⎝

⎛ ∆=

RTG

MhN #

expρηhN = 3.99 . 10-10 Js/mol

∑= ii MxM∑= iix ρρ ρi density of pure (i)

Mi atomic mass of pure (i)∆G# Gibbs energy of activation

Extrapolation by knowledge of excess Gibbs energy Gxs

∆Gi# = f(T) Gibbs energy of activation of pure (i)

( )∑∑ ∑ +++∆=∆<

ixs

iiji

jiii xTGxxRTxxRTGxG ,ln3##


User-Friendly Interface 31

plus extra buttonsSame as Pandat



Conclusion32

ApplicationsAlloy developmentProcess optimization

Thermodynamic databasesQuality of data is vital - scrutinizing published datasets Link key experiments to modeling

☺

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