analysis of high angle boundaries in directionally solidified
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IOP Conference Series Materials Science and Engineering
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Analysis of high angle boundaries in directionallysolidified turbine blade made of CMSX-4regsuperalloyTo cite this article B Chmiela and M Sozaska 2011 IOP Conf Ser Mater Sci Eng 22 012008
View the article online for updates and enhancements
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Analysis of high angle boundaries in directionally solidified
turbine blade made of CMSX-4reg superalloy
B Chmiela and M Sozańska
Department of Materials Science and Metallurgy Silesian University of Technology
40-019 Katowice Poland
E-mail bartoszchmielapolslpl
Abstract High angle boundary (HAB) and low angle boundary (LAB) are casting defects of
single crystal (SX) and directionally solidified (DS) turbine blades and decrease the lifetime of
these blades during service During directional solidification primary dendrite arms grow in
the opposite direction of the thermal gradient direction and perpendicular to the mushy zone
interface When this interface is not flat primary dendrite arms growing in various areas of the
mushy zone are characterized by different growth directions Then after the primary dendrite
tips contact each other LABs or HABs form (depending on the angle between the directions of
the primary dendrite arms) This paper presents characterization studies of HABs in a DS
turbine blade made of CMSX-4reg superalloy The blade was characterized by three columnar
grains with HABs Qualitative and quantitative analyses of the HABs using electron
backscatter diffraction in a scanning electron microscope (SEM-EBSD) were carried out The
EBSD technique helped to determine the crystallographic orientation of the grains near the
HAB misorientation angles between grains (and inside each grain) and the angle of deviation
between the [001] direction and the blade axis
1 Introduction
Modern aero engines have been improved based on increasing the thrust and thermal efficiency In
order to accomplish this improvement it is necessary to increase the operating temperature in the
combustion chamber Therefore single crystal (SX) and directionally solidified (DS) superalloy
turbine blades have been developed to replace the commonly used polycrystalline equiaxed turbine
blades [1 2]
Modern SX and DS turbine blades are produced by the Bridgman bottom seed method The
preferred crystallographic orientation of the seed is usually [001] In practise a deviation between the
blade axis and the [001] direction of up to 12deg is acceptable But to achieve the best mechanical
properties (especially fatigue strength under variable load conditions) the angle between the growth
direction and the [001] direction must be as small as possible [1 2] Furthermore in DS blades the
misorientation between neighbouring columnar grains should not exceed 15deg to avoid a high angle
boundary (HAB) Thus it is necessary to accurately monitor the crystallographic orientation during
directional solidification Unfortunately for many reasons many disturbances in the solidification
front take place and dendrites in different areas of the casting grow in different directions Then after
the primary dendrite tips contact each other low angle boundaries (LABs) or HABs form (depending
on the angle between the primary dendrite arm directions) [3] Incorrect orientation of the seed (or
heterogeneous nucleation by foreign particles [4]) can promote the growth of a stray grain thus
Technologies and Properties of Modern Utilised Materials IOP PublishingIOP Conf Series Materials Science and Engineering 22 (2011) 012008 doi1010881757-899X221012008
Published under licence by IOP Publishing Ltd 1
forming a HAB with the SX or causing too high a misorientation among the columnar grains in the DS
castings Because these defects have a negative effect on the mechanical properties of the SX and DS
blades they should be characterized in detail to understand the formation mechanisms and improve
the solidification process
This paper presents an analysis of HABs in an experimental turbine blade made of CMSX-4reg
nickel-base superalloy Qualitative and quantitative analyses of the many aspects of crystallographic
orientation were conducted using electron backscatter diffraction (EBSD) in a scanning electron
microscope (SEM)
2 Material and experimental procedure
An experimental DS turbine blade made of CMSX-4reg superalloy was used in this study The chemical
composition of the alloy is shown in table 1 The directional solidification process was performed in a
Bridgman-type furnace Three differently oriented seeds were used in the process
Table 1 Chemical composition of CMSX-4reg superalloy
Element Ni Cr Co Mo W Ta Ti Al Hf Re
Concentration (wt ) bal 65 9 06 6 65 1 56 01 3
The withdrawal rate was 000005 m s-1
The blade surface was etched in a solution of 14 cm3 HCl
21 cm3 H2O and 8 g FeCl3 to reveal columnar grains
Investigations of the microstructure and crystallographic orientation were performed on the one
cross-section of the upper part of the blade because the highest deviation from the preferred
orientation usually is found in this part [5] The blade was cut perpendicular to the main axis and the
obtained specimen was ground and polished according to a procedure that was slightly modified from
one described earlier [6 7] (diamond suspension grit sizes of 9 μm 3 μm 1 μm and 025 μm
005 μm alumina suspension) The specimen was etched in a solution of 100 cm3 HCl 100 cm
3 HNO3
100 cm3 H2O and 3 g MoO3 for metallographic examination A macrostructural examination of the
blade surface was performed using a stereoscopic microscope (Olympus SZX-9) The microstructure
and crystallographic orientation were characterized using an SEM (Hitachi S-3400N) equipped with
an energy dispersive spectrometer (EDS) (Thermo NORAN (System Six)) and electron backscatter
diffraction detector (INCA HKL Nordlys II (Channel 5)) For orientation analysis the specimen was
additionally vibratory polished (alumina suspension 005 μm grit size) for 5 hours to obtain as low
surface roughness as possible
3 Results and discussion
Figure 1 shows the blade surface with the columnar grains revealed Some deviation of the dendrite
growth direction from the heat flow direction is visible
Figure 1 Columnar grains on the surface of the turbine blade
Technologies and Properties of Modern Utilised Materials IOP PublishingIOP Conf Series Materials Science and Engineering 22 (2011) 012008 doi1010881757-899X221012008
2
The dendritic structure on the cross-section of the blade is shown in figure 2 The asymmetry of the
secondary dendrite arms is a result of the deviation of the dendrite growth direction from the heat flow
direction the heat flow disturbances and the thermal gradient The deviation of the primary dendrite
arms is mainly a result of the initial seed orientation [8] and causes the overgrowth of secondary arms
on one side of the primary arms [9]
Figure 2 Dendritic structure on the cross-section of the blade
An SEM micrograph of the cross-section reveals the grain boundary area and the different
orientations of the columnar grains Crystallographic orientation analysis using EBSD allowed
detailed characterization of the HAB Qualitative evaluation of the orientation was performed by
comparing the Kikuchi patterns of both columnar grains Figure 3 shows two different Kikuchi
patterns originating from the two columnar grains
Figure 3 Kikuchi patterns of two columnar grains near the high angle boundary
(a) pattern from grain 1and (b) pattern from grain 2
Crystallographic orientation maps were taken in the area surrounding the HAB (figure 4)
Orientation maps reveal the grain boundary shape which is not clearly visible on the SEM
micrograph Different colours assigned to the grains correspond to different crystallographic
orientations
Technologies and Properties of Modern Utilised Materials IOP PublishingIOP Conf Series Materials Science and Engineering 22 (2011) 012008 doi1010881757-899X221012008
3
Figure 4 Orientation maps of the high angle boundary area (a) map with Euler contrast and (b) map
with inverse pole figures with gray scale contrast (black line - high angle boundary)
An orientation map with inverse pole figures (IPFs) with gray scale contrast (figure 4b) aids in the
semi quantitative evaluation of crystallographic orientations Figure 4b shows that both columnar
grains deviate from the preferred [001] orientation Using the saved quantitative orientation data from
each point on the orientation map misorientation profiles in the grain boundary area and inside each
grain were determined Misorientation profiles are plots of the misorientation angles as a function of
the distance along a line (chosen arbitrarily) The misorientation describes the orientation difference
between grains (or micro areas in general) by rotating their crystal coordinate systems into
coincidence The misorientation profile in the grain boundary area which has a misorientation of
about 40deg directly shows the presence of a HAB - figure 5
Figure 5 Misorientation profile in the HAB area
However the misorientation profile inside each columnar grain reveals very small differences in
orientation that do not exceed 1degmdashfigure 6 These results indicate that columnar grains are single
Technologies and Properties of Modern Utilised Materials IOP PublishingIOP Conf Series Materials Science and Engineering 22 (2011) 012008 doi1010881757-899X221012008
4
crystals with a mosaic structure In this mosaic structure the lower misorientation values of mosaic
blocks (01degndash 03deg) are associated with the dendrite interiors but higher misorientation values are
associated with dendritendashinterdendritic area boundaries [10]
Figure 6 Misorientation profiles inside columnar grains (a) grain 1 and (b) grain 2
Quantitative evaluation of the orientation in relation to the cross-section plane was performed
based on pole figures (PFs) and inverse pole figures (IPFs) PFs and IPFs were determined for each
columnar grain (figure 7 and figure 8) and for the HAB area (figure 9)
Figure 7 Pole figures and inverse pole figures
for grain 1 Figure 8 Pole figures and inverse pole figures for
grain 2
PFs 100 110 and 111 directly reveal that the angle of deviation between the [001] direction
and the blade growth direction is similar for both grains Table 2 presents the values of the angles
between the [001] direction and the blade growth direction for each grain
Table 2 Angles between the [001] direction and the blade axis
Grain Angle between [001]
direction and blade axis (deg)
1 97
2 102
The rotation angle between the [100] directions of both grains is 425deg The obtained results show that
the columnar grains are rotated relative to each other with a simultaneous deviation from the [001]
Technologies and Properties of Modern Utilised Materials IOP PublishingIOP Conf Series Materials Science and Engineering 22 (2011) 012008 doi1010881757-899X221012008
5
orientation One should note that the deviation of the primary dendrite arms is quite large (about 10deg)
near the maximum acceptable value
Figure 9 Pole figures and inverse pole figures for the HAB area (points in squares are related to
grain 2)
4 Conclusions
A high angle boundary (HAB) is one example of the many casting defects in single crystal (SX) and
directionally solidified (DS) turbine blades HABs strongly deteriorate the mechanical properties of
the blade especially in the case of a stray grain in the SX blade Moreover the deterioration of the
mechanical properties is greater while the slope of the grain boundary plane in relation to the crystal
growth direction increases [11] The investigation shows that employing the correct seeding process
and maintaining heat flow control are extremely important because if they are not optimized
deviations that are too high from the preferred orientation occurmdasheg HABs form
Control examinations involving the evaluation of the superalloy turbine blade microstructure and
orientation should be standard These techniques offer electron backscatter diffraction on the scanning
electron microscope which allows the evaluation of even small misorientations in micro areas
Acknowledgements
Financial support of Structural Funds in the Operational Programme-Innovative Economy (IE OP)
financed from the European Regional Development Fund-Project No POIG010102-00-01508 is
gratefully acknowledged
Technologies and Properties of Modern Utilised Materials IOP PublishingIOP Conf Series Materials Science and Engineering 22 (2011) 012008 doi1010881757-899X221012008
6
References
[1] Reed R C 2006 The Superalloys Fundamentals and Applications (Cambridge University
Press)[2] Durand-Charre M 1997 The Microstructure of Superalloys (Amsterdam Overseas
Publishers Association)
[3] Yu K-O (Oscar) et al 2002 Modelling for Casting and Solidification Processing (Marcel
Dekker Inc)
[4] Ford D A and Wallbank J 1998 Int J Cast Metals Res 11 23
[5] Onyszko A Bogdanowicz W Nowotnik A Kubiak K and Sieniawski J 2010 Inż Mater 3 629
[6] Szczotok A and Sozańska M 2009 Prakt Metall 46 1
[7] Szczotok A Chmiela B and Sozańska M 2010 Inż Mater 3 695
[8] Esaka H Daimon H Natsuma Y Ohsasa K and Tamura M 2002 Mater Trans JIM 43 1312
[9] Zhao X Liu L Yu Z Zhang W and Fu H 2010 Mat Charact 61 7
[10] Bruumlckner U Epishin A and Link T 1997 Acta Mater 45 5223
[11] Chen Q Z Jones C N and Knowles D M 2004 Mat Sci Eng A 385 402
Technologies and Properties of Modern Utilised Materials IOP PublishingIOP Conf Series Materials Science and Engineering 22 (2011) 012008 doi1010881757-899X221012008
7
Analysis of high angle boundaries in directionally solidified
turbine blade made of CMSX-4reg superalloy
B Chmiela and M Sozańska
Department of Materials Science and Metallurgy Silesian University of Technology
40-019 Katowice Poland
E-mail bartoszchmielapolslpl
Abstract High angle boundary (HAB) and low angle boundary (LAB) are casting defects of
single crystal (SX) and directionally solidified (DS) turbine blades and decrease the lifetime of
these blades during service During directional solidification primary dendrite arms grow in
the opposite direction of the thermal gradient direction and perpendicular to the mushy zone
interface When this interface is not flat primary dendrite arms growing in various areas of the
mushy zone are characterized by different growth directions Then after the primary dendrite
tips contact each other LABs or HABs form (depending on the angle between the directions of
the primary dendrite arms) This paper presents characterization studies of HABs in a DS
turbine blade made of CMSX-4reg superalloy The blade was characterized by three columnar
grains with HABs Qualitative and quantitative analyses of the HABs using electron
backscatter diffraction in a scanning electron microscope (SEM-EBSD) were carried out The
EBSD technique helped to determine the crystallographic orientation of the grains near the
HAB misorientation angles between grains (and inside each grain) and the angle of deviation
between the [001] direction and the blade axis
1 Introduction
Modern aero engines have been improved based on increasing the thrust and thermal efficiency In
order to accomplish this improvement it is necessary to increase the operating temperature in the
combustion chamber Therefore single crystal (SX) and directionally solidified (DS) superalloy
turbine blades have been developed to replace the commonly used polycrystalline equiaxed turbine
blades [1 2]
Modern SX and DS turbine blades are produced by the Bridgman bottom seed method The
preferred crystallographic orientation of the seed is usually [001] In practise a deviation between the
blade axis and the [001] direction of up to 12deg is acceptable But to achieve the best mechanical
properties (especially fatigue strength under variable load conditions) the angle between the growth
direction and the [001] direction must be as small as possible [1 2] Furthermore in DS blades the
misorientation between neighbouring columnar grains should not exceed 15deg to avoid a high angle
boundary (HAB) Thus it is necessary to accurately monitor the crystallographic orientation during
directional solidification Unfortunately for many reasons many disturbances in the solidification
front take place and dendrites in different areas of the casting grow in different directions Then after
the primary dendrite tips contact each other low angle boundaries (LABs) or HABs form (depending
on the angle between the primary dendrite arm directions) [3] Incorrect orientation of the seed (or
heterogeneous nucleation by foreign particles [4]) can promote the growth of a stray grain thus
Technologies and Properties of Modern Utilised Materials IOP PublishingIOP Conf Series Materials Science and Engineering 22 (2011) 012008 doi1010881757-899X221012008
Published under licence by IOP Publishing Ltd 1
forming a HAB with the SX or causing too high a misorientation among the columnar grains in the DS
castings Because these defects have a negative effect on the mechanical properties of the SX and DS
blades they should be characterized in detail to understand the formation mechanisms and improve
the solidification process
This paper presents an analysis of HABs in an experimental turbine blade made of CMSX-4reg
nickel-base superalloy Qualitative and quantitative analyses of the many aspects of crystallographic
orientation were conducted using electron backscatter diffraction (EBSD) in a scanning electron
microscope (SEM)
2 Material and experimental procedure
An experimental DS turbine blade made of CMSX-4reg superalloy was used in this study The chemical
composition of the alloy is shown in table 1 The directional solidification process was performed in a
Bridgman-type furnace Three differently oriented seeds were used in the process
Table 1 Chemical composition of CMSX-4reg superalloy
Element Ni Cr Co Mo W Ta Ti Al Hf Re
Concentration (wt ) bal 65 9 06 6 65 1 56 01 3
The withdrawal rate was 000005 m s-1
The blade surface was etched in a solution of 14 cm3 HCl
21 cm3 H2O and 8 g FeCl3 to reveal columnar grains
Investigations of the microstructure and crystallographic orientation were performed on the one
cross-section of the upper part of the blade because the highest deviation from the preferred
orientation usually is found in this part [5] The blade was cut perpendicular to the main axis and the
obtained specimen was ground and polished according to a procedure that was slightly modified from
one described earlier [6 7] (diamond suspension grit sizes of 9 μm 3 μm 1 μm and 025 μm
005 μm alumina suspension) The specimen was etched in a solution of 100 cm3 HCl 100 cm
3 HNO3
100 cm3 H2O and 3 g MoO3 for metallographic examination A macrostructural examination of the
blade surface was performed using a stereoscopic microscope (Olympus SZX-9) The microstructure
and crystallographic orientation were characterized using an SEM (Hitachi S-3400N) equipped with
an energy dispersive spectrometer (EDS) (Thermo NORAN (System Six)) and electron backscatter
diffraction detector (INCA HKL Nordlys II (Channel 5)) For orientation analysis the specimen was
additionally vibratory polished (alumina suspension 005 μm grit size) for 5 hours to obtain as low
surface roughness as possible
3 Results and discussion
Figure 1 shows the blade surface with the columnar grains revealed Some deviation of the dendrite
growth direction from the heat flow direction is visible
Figure 1 Columnar grains on the surface of the turbine blade
Technologies and Properties of Modern Utilised Materials IOP PublishingIOP Conf Series Materials Science and Engineering 22 (2011) 012008 doi1010881757-899X221012008
2
The dendritic structure on the cross-section of the blade is shown in figure 2 The asymmetry of the
secondary dendrite arms is a result of the deviation of the dendrite growth direction from the heat flow
direction the heat flow disturbances and the thermal gradient The deviation of the primary dendrite
arms is mainly a result of the initial seed orientation [8] and causes the overgrowth of secondary arms
on one side of the primary arms [9]
Figure 2 Dendritic structure on the cross-section of the blade
An SEM micrograph of the cross-section reveals the grain boundary area and the different
orientations of the columnar grains Crystallographic orientation analysis using EBSD allowed
detailed characterization of the HAB Qualitative evaluation of the orientation was performed by
comparing the Kikuchi patterns of both columnar grains Figure 3 shows two different Kikuchi
patterns originating from the two columnar grains
Figure 3 Kikuchi patterns of two columnar grains near the high angle boundary
(a) pattern from grain 1and (b) pattern from grain 2
Crystallographic orientation maps were taken in the area surrounding the HAB (figure 4)
Orientation maps reveal the grain boundary shape which is not clearly visible on the SEM
micrograph Different colours assigned to the grains correspond to different crystallographic
orientations
Technologies and Properties of Modern Utilised Materials IOP PublishingIOP Conf Series Materials Science and Engineering 22 (2011) 012008 doi1010881757-899X221012008
3
Figure 4 Orientation maps of the high angle boundary area (a) map with Euler contrast and (b) map
with inverse pole figures with gray scale contrast (black line - high angle boundary)
An orientation map with inverse pole figures (IPFs) with gray scale contrast (figure 4b) aids in the
semi quantitative evaluation of crystallographic orientations Figure 4b shows that both columnar
grains deviate from the preferred [001] orientation Using the saved quantitative orientation data from
each point on the orientation map misorientation profiles in the grain boundary area and inside each
grain were determined Misorientation profiles are plots of the misorientation angles as a function of
the distance along a line (chosen arbitrarily) The misorientation describes the orientation difference
between grains (or micro areas in general) by rotating their crystal coordinate systems into
coincidence The misorientation profile in the grain boundary area which has a misorientation of
about 40deg directly shows the presence of a HAB - figure 5
Figure 5 Misorientation profile in the HAB area
However the misorientation profile inside each columnar grain reveals very small differences in
orientation that do not exceed 1degmdashfigure 6 These results indicate that columnar grains are single
Technologies and Properties of Modern Utilised Materials IOP PublishingIOP Conf Series Materials Science and Engineering 22 (2011) 012008 doi1010881757-899X221012008
4
crystals with a mosaic structure In this mosaic structure the lower misorientation values of mosaic
blocks (01degndash 03deg) are associated with the dendrite interiors but higher misorientation values are
associated with dendritendashinterdendritic area boundaries [10]
Figure 6 Misorientation profiles inside columnar grains (a) grain 1 and (b) grain 2
Quantitative evaluation of the orientation in relation to the cross-section plane was performed
based on pole figures (PFs) and inverse pole figures (IPFs) PFs and IPFs were determined for each
columnar grain (figure 7 and figure 8) and for the HAB area (figure 9)
Figure 7 Pole figures and inverse pole figures
for grain 1 Figure 8 Pole figures and inverse pole figures for
grain 2
PFs 100 110 and 111 directly reveal that the angle of deviation between the [001] direction
and the blade growth direction is similar for both grains Table 2 presents the values of the angles
between the [001] direction and the blade growth direction for each grain
Table 2 Angles between the [001] direction and the blade axis
Grain Angle between [001]
direction and blade axis (deg)
1 97
2 102
The rotation angle between the [100] directions of both grains is 425deg The obtained results show that
the columnar grains are rotated relative to each other with a simultaneous deviation from the [001]
Technologies and Properties of Modern Utilised Materials IOP PublishingIOP Conf Series Materials Science and Engineering 22 (2011) 012008 doi1010881757-899X221012008
5
orientation One should note that the deviation of the primary dendrite arms is quite large (about 10deg)
near the maximum acceptable value
Figure 9 Pole figures and inverse pole figures for the HAB area (points in squares are related to
grain 2)
4 Conclusions
A high angle boundary (HAB) is one example of the many casting defects in single crystal (SX) and
directionally solidified (DS) turbine blades HABs strongly deteriorate the mechanical properties of
the blade especially in the case of a stray grain in the SX blade Moreover the deterioration of the
mechanical properties is greater while the slope of the grain boundary plane in relation to the crystal
growth direction increases [11] The investigation shows that employing the correct seeding process
and maintaining heat flow control are extremely important because if they are not optimized
deviations that are too high from the preferred orientation occurmdasheg HABs form
Control examinations involving the evaluation of the superalloy turbine blade microstructure and
orientation should be standard These techniques offer electron backscatter diffraction on the scanning
electron microscope which allows the evaluation of even small misorientations in micro areas
Acknowledgements
Financial support of Structural Funds in the Operational Programme-Innovative Economy (IE OP)
financed from the European Regional Development Fund-Project No POIG010102-00-01508 is
gratefully acknowledged
Technologies and Properties of Modern Utilised Materials IOP PublishingIOP Conf Series Materials Science and Engineering 22 (2011) 012008 doi1010881757-899X221012008
6
References
[1] Reed R C 2006 The Superalloys Fundamentals and Applications (Cambridge University
Press)[2] Durand-Charre M 1997 The Microstructure of Superalloys (Amsterdam Overseas
Publishers Association)
[3] Yu K-O (Oscar) et al 2002 Modelling for Casting and Solidification Processing (Marcel
Dekker Inc)
[4] Ford D A and Wallbank J 1998 Int J Cast Metals Res 11 23
[5] Onyszko A Bogdanowicz W Nowotnik A Kubiak K and Sieniawski J 2010 Inż Mater 3 629
[6] Szczotok A and Sozańska M 2009 Prakt Metall 46 1
[7] Szczotok A Chmiela B and Sozańska M 2010 Inż Mater 3 695
[8] Esaka H Daimon H Natsuma Y Ohsasa K and Tamura M 2002 Mater Trans JIM 43 1312
[9] Zhao X Liu L Yu Z Zhang W and Fu H 2010 Mat Charact 61 7
[10] Bruumlckner U Epishin A and Link T 1997 Acta Mater 45 5223
[11] Chen Q Z Jones C N and Knowles D M 2004 Mat Sci Eng A 385 402
Technologies and Properties of Modern Utilised Materials IOP PublishingIOP Conf Series Materials Science and Engineering 22 (2011) 012008 doi1010881757-899X221012008
7
forming a HAB with the SX or causing too high a misorientation among the columnar grains in the DS
castings Because these defects have a negative effect on the mechanical properties of the SX and DS
blades they should be characterized in detail to understand the formation mechanisms and improve
the solidification process
This paper presents an analysis of HABs in an experimental turbine blade made of CMSX-4reg
nickel-base superalloy Qualitative and quantitative analyses of the many aspects of crystallographic
orientation were conducted using electron backscatter diffraction (EBSD) in a scanning electron
microscope (SEM)
2 Material and experimental procedure
An experimental DS turbine blade made of CMSX-4reg superalloy was used in this study The chemical
composition of the alloy is shown in table 1 The directional solidification process was performed in a
Bridgman-type furnace Three differently oriented seeds were used in the process
Table 1 Chemical composition of CMSX-4reg superalloy
Element Ni Cr Co Mo W Ta Ti Al Hf Re
Concentration (wt ) bal 65 9 06 6 65 1 56 01 3
The withdrawal rate was 000005 m s-1
The blade surface was etched in a solution of 14 cm3 HCl
21 cm3 H2O and 8 g FeCl3 to reveal columnar grains
Investigations of the microstructure and crystallographic orientation were performed on the one
cross-section of the upper part of the blade because the highest deviation from the preferred
orientation usually is found in this part [5] The blade was cut perpendicular to the main axis and the
obtained specimen was ground and polished according to a procedure that was slightly modified from
one described earlier [6 7] (diamond suspension grit sizes of 9 μm 3 μm 1 μm and 025 μm
005 μm alumina suspension) The specimen was etched in a solution of 100 cm3 HCl 100 cm
3 HNO3
100 cm3 H2O and 3 g MoO3 for metallographic examination A macrostructural examination of the
blade surface was performed using a stereoscopic microscope (Olympus SZX-9) The microstructure
and crystallographic orientation were characterized using an SEM (Hitachi S-3400N) equipped with
an energy dispersive spectrometer (EDS) (Thermo NORAN (System Six)) and electron backscatter
diffraction detector (INCA HKL Nordlys II (Channel 5)) For orientation analysis the specimen was
additionally vibratory polished (alumina suspension 005 μm grit size) for 5 hours to obtain as low
surface roughness as possible
3 Results and discussion
Figure 1 shows the blade surface with the columnar grains revealed Some deviation of the dendrite
growth direction from the heat flow direction is visible
Figure 1 Columnar grains on the surface of the turbine blade
Technologies and Properties of Modern Utilised Materials IOP PublishingIOP Conf Series Materials Science and Engineering 22 (2011) 012008 doi1010881757-899X221012008
2
The dendritic structure on the cross-section of the blade is shown in figure 2 The asymmetry of the
secondary dendrite arms is a result of the deviation of the dendrite growth direction from the heat flow
direction the heat flow disturbances and the thermal gradient The deviation of the primary dendrite
arms is mainly a result of the initial seed orientation [8] and causes the overgrowth of secondary arms
on one side of the primary arms [9]
Figure 2 Dendritic structure on the cross-section of the blade
An SEM micrograph of the cross-section reveals the grain boundary area and the different
orientations of the columnar grains Crystallographic orientation analysis using EBSD allowed
detailed characterization of the HAB Qualitative evaluation of the orientation was performed by
comparing the Kikuchi patterns of both columnar grains Figure 3 shows two different Kikuchi
patterns originating from the two columnar grains
Figure 3 Kikuchi patterns of two columnar grains near the high angle boundary
(a) pattern from grain 1and (b) pattern from grain 2
Crystallographic orientation maps were taken in the area surrounding the HAB (figure 4)
Orientation maps reveal the grain boundary shape which is not clearly visible on the SEM
micrograph Different colours assigned to the grains correspond to different crystallographic
orientations
Technologies and Properties of Modern Utilised Materials IOP PublishingIOP Conf Series Materials Science and Engineering 22 (2011) 012008 doi1010881757-899X221012008
3
Figure 4 Orientation maps of the high angle boundary area (a) map with Euler contrast and (b) map
with inverse pole figures with gray scale contrast (black line - high angle boundary)
An orientation map with inverse pole figures (IPFs) with gray scale contrast (figure 4b) aids in the
semi quantitative evaluation of crystallographic orientations Figure 4b shows that both columnar
grains deviate from the preferred [001] orientation Using the saved quantitative orientation data from
each point on the orientation map misorientation profiles in the grain boundary area and inside each
grain were determined Misorientation profiles are plots of the misorientation angles as a function of
the distance along a line (chosen arbitrarily) The misorientation describes the orientation difference
between grains (or micro areas in general) by rotating their crystal coordinate systems into
coincidence The misorientation profile in the grain boundary area which has a misorientation of
about 40deg directly shows the presence of a HAB - figure 5
Figure 5 Misorientation profile in the HAB area
However the misorientation profile inside each columnar grain reveals very small differences in
orientation that do not exceed 1degmdashfigure 6 These results indicate that columnar grains are single
Technologies and Properties of Modern Utilised Materials IOP PublishingIOP Conf Series Materials Science and Engineering 22 (2011) 012008 doi1010881757-899X221012008
4
crystals with a mosaic structure In this mosaic structure the lower misorientation values of mosaic
blocks (01degndash 03deg) are associated with the dendrite interiors but higher misorientation values are
associated with dendritendashinterdendritic area boundaries [10]
Figure 6 Misorientation profiles inside columnar grains (a) grain 1 and (b) grain 2
Quantitative evaluation of the orientation in relation to the cross-section plane was performed
based on pole figures (PFs) and inverse pole figures (IPFs) PFs and IPFs were determined for each
columnar grain (figure 7 and figure 8) and for the HAB area (figure 9)
Figure 7 Pole figures and inverse pole figures
for grain 1 Figure 8 Pole figures and inverse pole figures for
grain 2
PFs 100 110 and 111 directly reveal that the angle of deviation between the [001] direction
and the blade growth direction is similar for both grains Table 2 presents the values of the angles
between the [001] direction and the blade growth direction for each grain
Table 2 Angles between the [001] direction and the blade axis
Grain Angle between [001]
direction and blade axis (deg)
1 97
2 102
The rotation angle between the [100] directions of both grains is 425deg The obtained results show that
the columnar grains are rotated relative to each other with a simultaneous deviation from the [001]
Technologies and Properties of Modern Utilised Materials IOP PublishingIOP Conf Series Materials Science and Engineering 22 (2011) 012008 doi1010881757-899X221012008
5
orientation One should note that the deviation of the primary dendrite arms is quite large (about 10deg)
near the maximum acceptable value
Figure 9 Pole figures and inverse pole figures for the HAB area (points in squares are related to
grain 2)
4 Conclusions
A high angle boundary (HAB) is one example of the many casting defects in single crystal (SX) and
directionally solidified (DS) turbine blades HABs strongly deteriorate the mechanical properties of
the blade especially in the case of a stray grain in the SX blade Moreover the deterioration of the
mechanical properties is greater while the slope of the grain boundary plane in relation to the crystal
growth direction increases [11] The investigation shows that employing the correct seeding process
and maintaining heat flow control are extremely important because if they are not optimized
deviations that are too high from the preferred orientation occurmdasheg HABs form
Control examinations involving the evaluation of the superalloy turbine blade microstructure and
orientation should be standard These techniques offer electron backscatter diffraction on the scanning
electron microscope which allows the evaluation of even small misorientations in micro areas
Acknowledgements
Financial support of Structural Funds in the Operational Programme-Innovative Economy (IE OP)
financed from the European Regional Development Fund-Project No POIG010102-00-01508 is
gratefully acknowledged
Technologies and Properties of Modern Utilised Materials IOP PublishingIOP Conf Series Materials Science and Engineering 22 (2011) 012008 doi1010881757-899X221012008
6
References
[1] Reed R C 2006 The Superalloys Fundamentals and Applications (Cambridge University
Press)[2] Durand-Charre M 1997 The Microstructure of Superalloys (Amsterdam Overseas
Publishers Association)
[3] Yu K-O (Oscar) et al 2002 Modelling for Casting and Solidification Processing (Marcel
Dekker Inc)
[4] Ford D A and Wallbank J 1998 Int J Cast Metals Res 11 23
[5] Onyszko A Bogdanowicz W Nowotnik A Kubiak K and Sieniawski J 2010 Inż Mater 3 629
[6] Szczotok A and Sozańska M 2009 Prakt Metall 46 1
[7] Szczotok A Chmiela B and Sozańska M 2010 Inż Mater 3 695
[8] Esaka H Daimon H Natsuma Y Ohsasa K and Tamura M 2002 Mater Trans JIM 43 1312
[9] Zhao X Liu L Yu Z Zhang W and Fu H 2010 Mat Charact 61 7
[10] Bruumlckner U Epishin A and Link T 1997 Acta Mater 45 5223
[11] Chen Q Z Jones C N and Knowles D M 2004 Mat Sci Eng A 385 402
Technologies and Properties of Modern Utilised Materials IOP PublishingIOP Conf Series Materials Science and Engineering 22 (2011) 012008 doi1010881757-899X221012008
7
The dendritic structure on the cross-section of the blade is shown in figure 2 The asymmetry of the
secondary dendrite arms is a result of the deviation of the dendrite growth direction from the heat flow
direction the heat flow disturbances and the thermal gradient The deviation of the primary dendrite
arms is mainly a result of the initial seed orientation [8] and causes the overgrowth of secondary arms
on one side of the primary arms [9]
Figure 2 Dendritic structure on the cross-section of the blade
An SEM micrograph of the cross-section reveals the grain boundary area and the different
orientations of the columnar grains Crystallographic orientation analysis using EBSD allowed
detailed characterization of the HAB Qualitative evaluation of the orientation was performed by
comparing the Kikuchi patterns of both columnar grains Figure 3 shows two different Kikuchi
patterns originating from the two columnar grains
Figure 3 Kikuchi patterns of two columnar grains near the high angle boundary
(a) pattern from grain 1and (b) pattern from grain 2
Crystallographic orientation maps were taken in the area surrounding the HAB (figure 4)
Orientation maps reveal the grain boundary shape which is not clearly visible on the SEM
micrograph Different colours assigned to the grains correspond to different crystallographic
orientations
Technologies and Properties of Modern Utilised Materials IOP PublishingIOP Conf Series Materials Science and Engineering 22 (2011) 012008 doi1010881757-899X221012008
3
Figure 4 Orientation maps of the high angle boundary area (a) map with Euler contrast and (b) map
with inverse pole figures with gray scale contrast (black line - high angle boundary)
An orientation map with inverse pole figures (IPFs) with gray scale contrast (figure 4b) aids in the
semi quantitative evaluation of crystallographic orientations Figure 4b shows that both columnar
grains deviate from the preferred [001] orientation Using the saved quantitative orientation data from
each point on the orientation map misorientation profiles in the grain boundary area and inside each
grain were determined Misorientation profiles are plots of the misorientation angles as a function of
the distance along a line (chosen arbitrarily) The misorientation describes the orientation difference
between grains (or micro areas in general) by rotating their crystal coordinate systems into
coincidence The misorientation profile in the grain boundary area which has a misorientation of
about 40deg directly shows the presence of a HAB - figure 5
Figure 5 Misorientation profile in the HAB area
However the misorientation profile inside each columnar grain reveals very small differences in
orientation that do not exceed 1degmdashfigure 6 These results indicate that columnar grains are single
Technologies and Properties of Modern Utilised Materials IOP PublishingIOP Conf Series Materials Science and Engineering 22 (2011) 012008 doi1010881757-899X221012008
4
crystals with a mosaic structure In this mosaic structure the lower misorientation values of mosaic
blocks (01degndash 03deg) are associated with the dendrite interiors but higher misorientation values are
associated with dendritendashinterdendritic area boundaries [10]
Figure 6 Misorientation profiles inside columnar grains (a) grain 1 and (b) grain 2
Quantitative evaluation of the orientation in relation to the cross-section plane was performed
based on pole figures (PFs) and inverse pole figures (IPFs) PFs and IPFs were determined for each
columnar grain (figure 7 and figure 8) and for the HAB area (figure 9)
Figure 7 Pole figures and inverse pole figures
for grain 1 Figure 8 Pole figures and inverse pole figures for
grain 2
PFs 100 110 and 111 directly reveal that the angle of deviation between the [001] direction
and the blade growth direction is similar for both grains Table 2 presents the values of the angles
between the [001] direction and the blade growth direction for each grain
Table 2 Angles between the [001] direction and the blade axis
Grain Angle between [001]
direction and blade axis (deg)
1 97
2 102
The rotation angle between the [100] directions of both grains is 425deg The obtained results show that
the columnar grains are rotated relative to each other with a simultaneous deviation from the [001]
Technologies and Properties of Modern Utilised Materials IOP PublishingIOP Conf Series Materials Science and Engineering 22 (2011) 012008 doi1010881757-899X221012008
5
orientation One should note that the deviation of the primary dendrite arms is quite large (about 10deg)
near the maximum acceptable value
Figure 9 Pole figures and inverse pole figures for the HAB area (points in squares are related to
grain 2)
4 Conclusions
A high angle boundary (HAB) is one example of the many casting defects in single crystal (SX) and
directionally solidified (DS) turbine blades HABs strongly deteriorate the mechanical properties of
the blade especially in the case of a stray grain in the SX blade Moreover the deterioration of the
mechanical properties is greater while the slope of the grain boundary plane in relation to the crystal
growth direction increases [11] The investigation shows that employing the correct seeding process
and maintaining heat flow control are extremely important because if they are not optimized
deviations that are too high from the preferred orientation occurmdasheg HABs form
Control examinations involving the evaluation of the superalloy turbine blade microstructure and
orientation should be standard These techniques offer electron backscatter diffraction on the scanning
electron microscope which allows the evaluation of even small misorientations in micro areas
Acknowledgements
Financial support of Structural Funds in the Operational Programme-Innovative Economy (IE OP)
financed from the European Regional Development Fund-Project No POIG010102-00-01508 is
gratefully acknowledged
Technologies and Properties of Modern Utilised Materials IOP PublishingIOP Conf Series Materials Science and Engineering 22 (2011) 012008 doi1010881757-899X221012008
6
References
[1] Reed R C 2006 The Superalloys Fundamentals and Applications (Cambridge University
Press)[2] Durand-Charre M 1997 The Microstructure of Superalloys (Amsterdam Overseas
Publishers Association)
[3] Yu K-O (Oscar) et al 2002 Modelling for Casting and Solidification Processing (Marcel
Dekker Inc)
[4] Ford D A and Wallbank J 1998 Int J Cast Metals Res 11 23
[5] Onyszko A Bogdanowicz W Nowotnik A Kubiak K and Sieniawski J 2010 Inż Mater 3 629
[6] Szczotok A and Sozańska M 2009 Prakt Metall 46 1
[7] Szczotok A Chmiela B and Sozańska M 2010 Inż Mater 3 695
[8] Esaka H Daimon H Natsuma Y Ohsasa K and Tamura M 2002 Mater Trans JIM 43 1312
[9] Zhao X Liu L Yu Z Zhang W and Fu H 2010 Mat Charact 61 7
[10] Bruumlckner U Epishin A and Link T 1997 Acta Mater 45 5223
[11] Chen Q Z Jones C N and Knowles D M 2004 Mat Sci Eng A 385 402
Technologies and Properties of Modern Utilised Materials IOP PublishingIOP Conf Series Materials Science and Engineering 22 (2011) 012008 doi1010881757-899X221012008
7
Figure 4 Orientation maps of the high angle boundary area (a) map with Euler contrast and (b) map
with inverse pole figures with gray scale contrast (black line - high angle boundary)
An orientation map with inverse pole figures (IPFs) with gray scale contrast (figure 4b) aids in the
semi quantitative evaluation of crystallographic orientations Figure 4b shows that both columnar
grains deviate from the preferred [001] orientation Using the saved quantitative orientation data from
each point on the orientation map misorientation profiles in the grain boundary area and inside each
grain were determined Misorientation profiles are plots of the misorientation angles as a function of
the distance along a line (chosen arbitrarily) The misorientation describes the orientation difference
between grains (or micro areas in general) by rotating their crystal coordinate systems into
coincidence The misorientation profile in the grain boundary area which has a misorientation of
about 40deg directly shows the presence of a HAB - figure 5
Figure 5 Misorientation profile in the HAB area
However the misorientation profile inside each columnar grain reveals very small differences in
orientation that do not exceed 1degmdashfigure 6 These results indicate that columnar grains are single
Technologies and Properties of Modern Utilised Materials IOP PublishingIOP Conf Series Materials Science and Engineering 22 (2011) 012008 doi1010881757-899X221012008
4
crystals with a mosaic structure In this mosaic structure the lower misorientation values of mosaic
blocks (01degndash 03deg) are associated with the dendrite interiors but higher misorientation values are
associated with dendritendashinterdendritic area boundaries [10]
Figure 6 Misorientation profiles inside columnar grains (a) grain 1 and (b) grain 2
Quantitative evaluation of the orientation in relation to the cross-section plane was performed
based on pole figures (PFs) and inverse pole figures (IPFs) PFs and IPFs were determined for each
columnar grain (figure 7 and figure 8) and for the HAB area (figure 9)
Figure 7 Pole figures and inverse pole figures
for grain 1 Figure 8 Pole figures and inverse pole figures for
grain 2
PFs 100 110 and 111 directly reveal that the angle of deviation between the [001] direction
and the blade growth direction is similar for both grains Table 2 presents the values of the angles
between the [001] direction and the blade growth direction for each grain
Table 2 Angles between the [001] direction and the blade axis
Grain Angle between [001]
direction and blade axis (deg)
1 97
2 102
The rotation angle between the [100] directions of both grains is 425deg The obtained results show that
the columnar grains are rotated relative to each other with a simultaneous deviation from the [001]
Technologies and Properties of Modern Utilised Materials IOP PublishingIOP Conf Series Materials Science and Engineering 22 (2011) 012008 doi1010881757-899X221012008
5
orientation One should note that the deviation of the primary dendrite arms is quite large (about 10deg)
near the maximum acceptable value
Figure 9 Pole figures and inverse pole figures for the HAB area (points in squares are related to
grain 2)
4 Conclusions
A high angle boundary (HAB) is one example of the many casting defects in single crystal (SX) and
directionally solidified (DS) turbine blades HABs strongly deteriorate the mechanical properties of
the blade especially in the case of a stray grain in the SX blade Moreover the deterioration of the
mechanical properties is greater while the slope of the grain boundary plane in relation to the crystal
growth direction increases [11] The investigation shows that employing the correct seeding process
and maintaining heat flow control are extremely important because if they are not optimized
deviations that are too high from the preferred orientation occurmdasheg HABs form
Control examinations involving the evaluation of the superalloy turbine blade microstructure and
orientation should be standard These techniques offer electron backscatter diffraction on the scanning
electron microscope which allows the evaluation of even small misorientations in micro areas
Acknowledgements
Financial support of Structural Funds in the Operational Programme-Innovative Economy (IE OP)
financed from the European Regional Development Fund-Project No POIG010102-00-01508 is
gratefully acknowledged
Technologies and Properties of Modern Utilised Materials IOP PublishingIOP Conf Series Materials Science and Engineering 22 (2011) 012008 doi1010881757-899X221012008
6
References
[1] Reed R C 2006 The Superalloys Fundamentals and Applications (Cambridge University
Press)[2] Durand-Charre M 1997 The Microstructure of Superalloys (Amsterdam Overseas
Publishers Association)
[3] Yu K-O (Oscar) et al 2002 Modelling for Casting and Solidification Processing (Marcel
Dekker Inc)
[4] Ford D A and Wallbank J 1998 Int J Cast Metals Res 11 23
[5] Onyszko A Bogdanowicz W Nowotnik A Kubiak K and Sieniawski J 2010 Inż Mater 3 629
[6] Szczotok A and Sozańska M 2009 Prakt Metall 46 1
[7] Szczotok A Chmiela B and Sozańska M 2010 Inż Mater 3 695
[8] Esaka H Daimon H Natsuma Y Ohsasa K and Tamura M 2002 Mater Trans JIM 43 1312
[9] Zhao X Liu L Yu Z Zhang W and Fu H 2010 Mat Charact 61 7
[10] Bruumlckner U Epishin A and Link T 1997 Acta Mater 45 5223
[11] Chen Q Z Jones C N and Knowles D M 2004 Mat Sci Eng A 385 402
Technologies and Properties of Modern Utilised Materials IOP PublishingIOP Conf Series Materials Science and Engineering 22 (2011) 012008 doi1010881757-899X221012008
7
crystals with a mosaic structure In this mosaic structure the lower misorientation values of mosaic
blocks (01degndash 03deg) are associated with the dendrite interiors but higher misorientation values are
associated with dendritendashinterdendritic area boundaries [10]
Figure 6 Misorientation profiles inside columnar grains (a) grain 1 and (b) grain 2
Quantitative evaluation of the orientation in relation to the cross-section plane was performed
based on pole figures (PFs) and inverse pole figures (IPFs) PFs and IPFs were determined for each
columnar grain (figure 7 and figure 8) and for the HAB area (figure 9)
Figure 7 Pole figures and inverse pole figures
for grain 1 Figure 8 Pole figures and inverse pole figures for
grain 2
PFs 100 110 and 111 directly reveal that the angle of deviation between the [001] direction
and the blade growth direction is similar for both grains Table 2 presents the values of the angles
between the [001] direction and the blade growth direction for each grain
Table 2 Angles between the [001] direction and the blade axis
Grain Angle between [001]
direction and blade axis (deg)
1 97
2 102
The rotation angle between the [100] directions of both grains is 425deg The obtained results show that
the columnar grains are rotated relative to each other with a simultaneous deviation from the [001]
Technologies and Properties of Modern Utilised Materials IOP PublishingIOP Conf Series Materials Science and Engineering 22 (2011) 012008 doi1010881757-899X221012008
5
orientation One should note that the deviation of the primary dendrite arms is quite large (about 10deg)
near the maximum acceptable value
Figure 9 Pole figures and inverse pole figures for the HAB area (points in squares are related to
grain 2)
4 Conclusions
A high angle boundary (HAB) is one example of the many casting defects in single crystal (SX) and
directionally solidified (DS) turbine blades HABs strongly deteriorate the mechanical properties of
the blade especially in the case of a stray grain in the SX blade Moreover the deterioration of the
mechanical properties is greater while the slope of the grain boundary plane in relation to the crystal
growth direction increases [11] The investigation shows that employing the correct seeding process
and maintaining heat flow control are extremely important because if they are not optimized
deviations that are too high from the preferred orientation occurmdasheg HABs form
Control examinations involving the evaluation of the superalloy turbine blade microstructure and
orientation should be standard These techniques offer electron backscatter diffraction on the scanning
electron microscope which allows the evaluation of even small misorientations in micro areas
Acknowledgements
Financial support of Structural Funds in the Operational Programme-Innovative Economy (IE OP)
financed from the European Regional Development Fund-Project No POIG010102-00-01508 is
gratefully acknowledged
Technologies and Properties of Modern Utilised Materials IOP PublishingIOP Conf Series Materials Science and Engineering 22 (2011) 012008 doi1010881757-899X221012008
6
References
[1] Reed R C 2006 The Superalloys Fundamentals and Applications (Cambridge University
Press)[2] Durand-Charre M 1997 The Microstructure of Superalloys (Amsterdam Overseas
Publishers Association)
[3] Yu K-O (Oscar) et al 2002 Modelling for Casting and Solidification Processing (Marcel
Dekker Inc)
[4] Ford D A and Wallbank J 1998 Int J Cast Metals Res 11 23
[5] Onyszko A Bogdanowicz W Nowotnik A Kubiak K and Sieniawski J 2010 Inż Mater 3 629
[6] Szczotok A and Sozańska M 2009 Prakt Metall 46 1
[7] Szczotok A Chmiela B and Sozańska M 2010 Inż Mater 3 695
[8] Esaka H Daimon H Natsuma Y Ohsasa K and Tamura M 2002 Mater Trans JIM 43 1312
[9] Zhao X Liu L Yu Z Zhang W and Fu H 2010 Mat Charact 61 7
[10] Bruumlckner U Epishin A and Link T 1997 Acta Mater 45 5223
[11] Chen Q Z Jones C N and Knowles D M 2004 Mat Sci Eng A 385 402
Technologies and Properties of Modern Utilised Materials IOP PublishingIOP Conf Series Materials Science and Engineering 22 (2011) 012008 doi1010881757-899X221012008
7
orientation One should note that the deviation of the primary dendrite arms is quite large (about 10deg)
near the maximum acceptable value
Figure 9 Pole figures and inverse pole figures for the HAB area (points in squares are related to
grain 2)
4 Conclusions
A high angle boundary (HAB) is one example of the many casting defects in single crystal (SX) and
directionally solidified (DS) turbine blades HABs strongly deteriorate the mechanical properties of
the blade especially in the case of a stray grain in the SX blade Moreover the deterioration of the
mechanical properties is greater while the slope of the grain boundary plane in relation to the crystal
growth direction increases [11] The investigation shows that employing the correct seeding process
and maintaining heat flow control are extremely important because if they are not optimized
deviations that are too high from the preferred orientation occurmdasheg HABs form
Control examinations involving the evaluation of the superalloy turbine blade microstructure and
orientation should be standard These techniques offer electron backscatter diffraction on the scanning
electron microscope which allows the evaluation of even small misorientations in micro areas
Acknowledgements
Financial support of Structural Funds in the Operational Programme-Innovative Economy (IE OP)
financed from the European Regional Development Fund-Project No POIG010102-00-01508 is
gratefully acknowledged
Technologies and Properties of Modern Utilised Materials IOP PublishingIOP Conf Series Materials Science and Engineering 22 (2011) 012008 doi1010881757-899X221012008
6
References
[1] Reed R C 2006 The Superalloys Fundamentals and Applications (Cambridge University
Press)[2] Durand-Charre M 1997 The Microstructure of Superalloys (Amsterdam Overseas
Publishers Association)
[3] Yu K-O (Oscar) et al 2002 Modelling for Casting and Solidification Processing (Marcel
Dekker Inc)
[4] Ford D A and Wallbank J 1998 Int J Cast Metals Res 11 23
[5] Onyszko A Bogdanowicz W Nowotnik A Kubiak K and Sieniawski J 2010 Inż Mater 3 629
[6] Szczotok A and Sozańska M 2009 Prakt Metall 46 1
[7] Szczotok A Chmiela B and Sozańska M 2010 Inż Mater 3 695
[8] Esaka H Daimon H Natsuma Y Ohsasa K and Tamura M 2002 Mater Trans JIM 43 1312
[9] Zhao X Liu L Yu Z Zhang W and Fu H 2010 Mat Charact 61 7
[10] Bruumlckner U Epishin A and Link T 1997 Acta Mater 45 5223
[11] Chen Q Z Jones C N and Knowles D M 2004 Mat Sci Eng A 385 402
Technologies and Properties of Modern Utilised Materials IOP PublishingIOP Conf Series Materials Science and Engineering 22 (2011) 012008 doi1010881757-899X221012008
7
References
[1] Reed R C 2006 The Superalloys Fundamentals and Applications (Cambridge University
Press)[2] Durand-Charre M 1997 The Microstructure of Superalloys (Amsterdam Overseas
Publishers Association)
[3] Yu K-O (Oscar) et al 2002 Modelling for Casting and Solidification Processing (Marcel
Dekker Inc)
[4] Ford D A and Wallbank J 1998 Int J Cast Metals Res 11 23
[5] Onyszko A Bogdanowicz W Nowotnik A Kubiak K and Sieniawski J 2010 Inż Mater 3 629
[6] Szczotok A and Sozańska M 2009 Prakt Metall 46 1
[7] Szczotok A Chmiela B and Sozańska M 2010 Inż Mater 3 695
[8] Esaka H Daimon H Natsuma Y Ohsasa K and Tamura M 2002 Mater Trans JIM 43 1312
[9] Zhao X Liu L Yu Z Zhang W and Fu H 2010 Mat Charact 61 7
[10] Bruumlckner U Epishin A and Link T 1997 Acta Mater 45 5223
[11] Chen Q Z Jones C N and Knowles D M 2004 Mat Sci Eng A 385 402
Technologies and Properties of Modern Utilised Materials IOP PublishingIOP Conf Series Materials Science and Engineering 22 (2011) 012008 doi1010881757-899X221012008
7
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