Copyright © Siemens AG 2009. All rights reserved.
Application of Thermo-Calc and
DICTRA in an Industrial SettingSebastian Piegert
Thermo-Calc/DICTRA Users MeetingAachen
2011-09-08/09
Page 2 2011-09-08 Siemens Energy Sector F PR GT EN MT 2 4Copyright © Siemens AG 2009. All rights reserved.
Piegert, S.
Outline
Introduction
MCrAlY Coating DevelopmentBackgroundSet-Up of DICTRA ModelResults of CalculationsExperimental Validation
Summary
Bla
de
1 o
f SG
T5-4
00
0F
mad
e o
f PW
A 1
48
3 S
X s
up
eral
loy
Page 3 2011-09-08 Siemens Energy Sector F PR GT EN MT 2 4Copyright © Siemens AG 2009. All rights reserved.
Piegert, S.
Organisational
Background
Base Material
CoatingJoining
sco
pe
of
MT
2 d
epar
tmen
t
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Piegert, S.
Areas of Application for Thermo-Calc and DICTRA
Coating-SubstrateInteraction
Estimation ofnon Conformances
and Failure Analysis
Heat Treatment Optimisation
Base MaterialCharacterisation
Braze Alloys andWeld FillersDevelopment
Base AlloyDevelopment
Thermo-Calc Version S with TTNi
7 Database
DICTRA 26 with MobNi1 Database
sco
pe
of
MT
2 d
epar
tmen
t
Page 5 2011-09-08 Siemens Energy Sector F PR GT EN MT 2 4Copyright © Siemens AG 2009. All rights reserved.
Piegert, S.
MCrAlY
Protective Coatings
Function:Corrosion and oxidation protectionAl and Cr reservoir for formation of Al2O3 and Cr2O3 protective scalesBond coat function for TBC
Composition (example):Co - 31Ni - 27Cr - 7.5Al - 0.5Y - 0.5Si
Microstructure:Cr and Al trapped in second phases (β (NiAl) or γ’ (Ni3Al)) in γ Ni-matrix
ApplicationThermal spraying (VPS or LPPS)Bonding heat treatment
aged
MC
rAlY
coat
ing
sys
tem
γ-layer
γ
+ β-layer
base material(γ
+ γ’-layer)
γ-layer
oxide layer
Page 6 2011-09-08 Siemens Energy Sector F PR GT EN MT 2 4Copyright © Siemens AG 2009. All rights reserved.
Piegert, S.
Problem Statement
Currently used system (baseline):Ni - Co - Cr - Al - 1.5Re - Y
ProblemRe price extremely high
RequestDevelop coating free of Re
Approachvariation of Cr contentslight increase of Al concentration
Base material PWA 1483 SXNi - 9Co - 12.2Cr - 1.9Mo - 3.8W - 5Ta -3.6Al - 4.1Ti
0.76
1.00
1.41
1.101.00 1.05
00.2
0.40.60.8
11.2
1.41.6
Alloy 1 baseline Alloy 4
c X/c
X0
/ -
Cr concentrationAl concentration
rela
tio
n o
f co
nst
itu
ents
ph
ase
dia
gra
m
Page 7 2011-09-08 Siemens Energy Sector F PR GT EN MT 2 4Copyright © Siemens AG 2009. All rights reserved.
Piegert, S.
Phase Diagrams of MCrAlY
Alloys
coating composed of β- and γ-phase above 900 °Cnear eutectic systems
simulation of substrate-coating interaction only with single phase systems so far
Alloy 1 (low Cr) Alloy 4 (high Cr)
bas
elin
e al
loy
e
xper
imen
tal a
lloys
Page 8 2011-09-08 Siemens Energy Sector F PR GT EN MT 2 4Copyright © Siemens AG 2009. All rights reserved.
Piegert, S.
Results of Ageing Trials at 1100 °C
Baseline materialPrecipitate free zoneHigh γ’-content directly on interface between γ-layer and γ - γ’-layer
Alloy 4 (high Cr)Almost no precipitate free layer in coatingLarge amount of base material transformsKirkendall porosity in Alloy 4 already after short times (« 300 h)
Alloy 1 (low Cr)Similar behaviour to baselineNo porosity
Allo
y4
(h
igh
Cr)
68
4 h
Bas
elin
e4
86
h
γ-layer
γ
+ β-layer
γ
+ γ’-layer
original interface
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Piegert, S.
Set-Up
Modelsingle cell problem (9 (8) species)double geometric gridelement distribution via “high step”functioneffective diffusion in dispersed system with γ’ and β:
*
Boundary ConditionsT = 1100 °C, tmax = 500 - 700 hisothermal, i.e. heating and cooling processes are not taken into account
Coating Substrate
200 µm 200 µm
Grid
Element Distribution
γ-matrix with γ’ and β
as dispersed phases
00.10.20.30.40.50.60.70.80.9
1
0 0.2 0.4 0.6 0.8 1
f Vγ / -
Def
f/Dγ
/ -
γ
γ
γ Df
fDupper
eff
⎟⎟⎟⎟
⎠
⎞
⎜⎜⎜⎜
⎝
⎛
−
−+=
310
331
effe
ctiv
ed
iffu
sio
nm
od
el
* D
ahl,
Hal
dan
d H
orse
wel
l: D
efec
t an
d D
iffu
sion
For
um
Vol
s. 2
58
-26
0 (
20
06
)
Page 10 2011-09-08 Siemens Energy Sector F PR GT EN MT 2 4Copyright © Siemens AG 2009. All rights reserved.
Piegert, S.
bas
elin
e
e
xper
imen
tal a
lloys
Phase Distribution
Alloy 1 and baseline behave similarprecipitate free zonepileup of γ’ at the interface
Alloy 4no precipitate free zonemoving interface
0.0
0.2
0.4
0.6
0.8
1.0
0.00E+00 1.00E-04 2.00E-04 3.00E-04 4.00E-04
distance / m
Np(
*) /
mol
/mol
GAMMA_Prime 1 hNiAl 1 hGAMMA_Prime 10 hNiAl 10 hNiAl 100 hGAMMA_Prime 100 hNiAl 300 hGamma_Prime 300 h
0.0
0.2
0.4
0.6
0.8
1.0
0.00E+00 1.00E-04 2.00E-04 3.00E-04 4.00E-04
distance / mm
Np(
*) /
mol
/mol
Gamma_Prime 1 hNiAl 1 hGamma_Prime 10 hNiAl 10 hGamma_Prime 100 hNiAl 100 hGamma_Prime 300 hNiAl 300 h
0.0
0.2
0.4
0.6
0.8
1.0
0.00E+00 1.00E-04 2.00E-04 3.00E-04 4.00E-04
distance / m
Np(
*) /
mol
/mol
GAMMA_Prime 1 hNiAl 1 hGAMMA_Prime 10 hNiAl 10 hNiAl 100 hGAMMA_Prime 100 hNiAl 300 hGamma_Prime 300 h
Alloy 1 (low Cr) Alloy 4 (high Cr)
baseline
Page 11 2011-09-08 Siemens Energy Sector F PR GT EN MT 2 4Copyright © Siemens AG 2009. All rights reserved.
Piegert, S.
Element Distribution
0.00
0.05
0.10
0.15
0.20
0.25
0.30
0.0E+00 1.0E-04 2.0E-04 3.0E-04 4.0E-04
distance / m
x(*)
/ m
ol/m
ol
x(Cr) 1 hx(Ta) 1 hx(Cr) 10 hx(Ta) 10 hx(Cr) 100 hx(Ta) 100 hx(Cr) 300 hx(Ta) 300 h
0.00
0.05
0.10
0.15
0.20
0.25
0.0E+00 1.0E-04 2.0E-04 3.0E-04 4.0E-04
distance / mx(
*) /
mol
/mol
x(Al) 1 hx(Ti) 1 hx(Al) 10 hx(Ti) 10 hx(Al) 100 hx(Ti) 100 hx(Al) 300 hx(Ti) 300 h
0.00
0.05
0.10
0.15
0.20
0.25
0.0E+00 1.0E-04 2.0E-04 3.0E-04 4.0E-04
distance / m
x(*)
/ m
ol/m
ol
x(Al) 1 hx(Ti) 1 hx(Al) 10 hx(Ti) 10 hx(Al) 100 hx(Ti) 100 hx(Al) 300 hx(Ti) 300 h
0.00
0.05
0.10
0.15
0.20
0.0E+00 1.0E-04 2.0E-04 3.0E-04 4.0E-04
distance / m
x(*)
/ m
ol/m
ol
x(Cr) 1 hx(Ta) 1 hx(Cr) 10 hx(Ta) 10 hx(Cr) 100 hx(Ta) 100 hx(Cr) 300 hx(Ta) 300 h
0.00
0.05
0.10
0.15
0.20
0.25
0.0E+00 1.0E-04 2.0E-04 3.0E-04 4.0E-04
distance / m
x(*)
/ m
ol/m
ol
x(Al) 1 hx(Ti) 1 hx(Al) 10 hx(Ti) 10 hx(Al) 100 hx(Ti) 100 hx(Al) 300 hx(Ti) 300 h
0.00
0.05
0.10
0.15
0.20
0.25
0.0E+00 1.0E-04 2.0E-04 3.0E-04 4.0E-04
distance / m
x(*)
/ m
ol/m
ol
x(Cr) 1 hx(Ta) 1 hx(Cr) 10 hx(Ta) 10 hx(Cr) 100 hx(Ta) 100 hx(Cr) 300 hx(Ta) 300 h
Alloy 1 (low Cr) Alloy 4 (high Cr)baseline
Page 12 2011-09-08 Siemens Energy Sector F PR GT EN MT 2 4Copyright © Siemens AG 2009. All rights reserved.
Piegert, S.
-40
-20
0
20
40
60
80
100
1.6E-04 1.8E-04 2.0E-04 2.2E-04 2.4E-04
distance / m
d(-J
Va)/d
z
Alloy4 0.5 hAlloy4 1 hAlloy4 10 hAlloy4 100 h
Tracking of Kirkendall
Porosity
zJc Va
Va ∂−∂
=Δ)(
∫ ∂−∂
=t
VaVa t
zJy
0
d)(
Change of the local vacancy content at a distinct position
Content of vacancies at a distinct position **
-40
-20
0
20
40
60
80
100
1.6E-04 1.8E-04 2.0E-04 2.2E-04 2.4E-04
distance / m
d(-J
Va)/d
z
baseline 0.5 hbaseline 1 hbaseline 10 hbaseline 100 h
-40
-20
0
20
40
60
80
100
1.6E-04 1.8E-04 2.0E-04 2.2E-04 2.4E-04
distance / m
d(-J
Va)/d
z
Alloy1 0.5 hAlloy1 1 hAlloy1 10 hAlloy1 100 h
Alloy 1 (low Cr) Alloy 4 (high Cr)baseline
** Höglund
and Ågren: Acta
mater 49 (2001) 1311-1317
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Piegert, S.
Experimental Validation (Composition Profiles)
Al profile Ti profileCr profile
Allo
y 4
(h
igh
Cr)
b
asel
ine
Page 14 2011-09-08 Siemens Energy Sector F PR GT EN MT 2 4Copyright © Siemens AG 2009. All rights reserved.
Piegert, S.
Experimental Validation (Microstructure)
γ−layer PWA1483
GAMMA_PrimeNiAl
Gamma_PrimeNiAl
γ−layer PWA1483
SEM
imag
es v
s. a
mo
un
t o
f p
has
es
Alloy 4 (high Cr)baseline
Page 15 2011-09-08 Siemens Energy Sector F PR GT EN MT 2 4Copyright © Siemens AG 2009. All rights reserved.
Piegert, S.
Summary
Thermo-Calc helps identifying MCrAlY coating systems
interdiffusion between MCrAlY and substrate can be handledlabyrinth factors for “diffusion none” phasescomplex material systems (9 species)TCP phases and minor elements not taken into accountqualitative prediction of Kirkendall porosity
experimental validationshape of composition profiles metno general labyrinth factor applicabledistribution of phases qualitatively shown
ROI: significant reduction of experiments ➙ faster time to market (>> 9:1)
Page 16 2011-09-08 Siemens Energy Sector F PR GT EN MT 2 4Copyright © Siemens AG 2009. All rights reserved.
Piegert, S.
Thank you for your attention!
Copyright ©
Siemens AG 2009. All rights reserved.
Page 17 2011-09-08 Siemens Energy Sector F PR GT EN MT 2 4Copyright © Siemens AG 2009. All rights reserved.
Piegert, S.
Disclaimer
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