Post on 06-Feb-2018
DICTRA Work in the SFB 370
Turbine Blade Process Chain
Turbine Blade Process Chain
Casting Heat Treatment Coating Testing
Team:
The Turbine Blade
Composition of the used superalloy CMSX-4 (wt.%)
Structure of superalloy after solidification
Bal0.60.126.41.06.52.96.59.65.61
NiMoHfWTiTaReCrCoAl
Reactions during solidification:
liquid
liquid
γ (fcc)
γ (fcc) γ‘ (fcc, ordered)
γ‘ (fcc, ordered)γ (fcc)
+
Primary Solidification
Transverse section of a quenched sample, EDX line scans indicated*
* Dexin Ma, Uwe Grafe, Materials Science and Engineering A270 (1999) 339-342
0 20 40 60 80 100 120 140 1600
2
4
6
8
10
12
Ta
Cs (
wt.-
%)
L (µm)0 20 40 60 80 100 120 140 160
0
2
4
6
8
10
12
Ti
Cr
Al
Cs (
wt.-
%)
L (µm)0 20 40 60 80 100 120 140 160
0
1
2
3
4
5
6
7
8
9
10
11
12
Re
W
Co
Cs (
wt.-
%)
L (µm)
γ
liquid
ckγ
ckl
vα DICTRA cell
Secondary Solidification
γ
liquid
ckγ
ckl
Equilibrium calculation agrees well with material dataScheil simulation differs significantly from diffusion calculation
1540 1560 1580 1600 1620 1640 16600.0
0.2
0.4
0.6
0.8
1.01540 1560 1580 1600 1620 1640 1660
Frac
tion
solid
Temperature (K)
DICTRA Equilibrium Gulliver-Scheil
γ‘
1598±3 K
1657 K
Solid State Transformation
γ
ckγ
γ‘
γ‘
0 20 40 60 80 100 120 140 1600.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
800 K
1400 K
1500 K
1550 K
Mol
e fra
ctio
n γ'
Distance (µm)
Interdendritic γ‘ is neglectedAmount of γ‘ correlates with microsegregations
Summary
• Diffusion simulations significantly improve the prediction of fractionsolid compared to the Scheil Model
• Calculated microsegregations agree well with experiments• Dependence of dispersed γ‘ on microsegregations can be shown
with DICTRA
DICTRA simulations are a valuable tool to simulate the microstructure of CMSX-4