Physical Metallurgy Division, PMD Indira Gandhi Centre for Atomic Research
Kalpakkam – 603 102, India
Characterisation of Microstructure in model
ODS Alloys
Arup Dasgupta
Physical Metallurgy Division
Indira Gandhi Centre for Atomic Research
Kalpakkam – 603102, INDIA
A collaborative work between IGCAR, Kalpakkam and
International Advanced Research Centre for Powder
Metallurgy and New Materials, Hyderabad
22 July 2008 1
WS&FT-08
Physical Metallurgy Division, PMD Indira Gandhi Centre for Atomic Research
Kalpakkam – 603 102, India
SCHEME
• The Issue
– What kind of alloy is under development
– Processing Scheme
– Importance of microstructure and microchemistry
investigations in alloy development
• This Talk
– Types of samples studies so far
– Results and Discussion
– Summary
22 July 2008 2
WS&FT-08
Physical Metallurgy Division, PMD Indira Gandhi Centre for Atomic Research
Kalpakkam – 603 102, India
The Alloy under development
9Cr-0.12C-2W-0.2Ti-0.35Y2O3 Ferritic/Martensitic steel chosen
because of advantages over austenitic stainless steels:
• Higher thermal conductivity
• Lower thermal expansion
• Lower void swelling during irradiation
• Excellent high temperature creep resistance
• W Mo replacement for solid solution strengthening;
reduced activation
• Ti Helps to get finer dispersoids
Mandate: Clad Tubes (6.6mm OD, 0.45mm thick, 2.65 m long)
22 July 2008 3
WS&FT-08
Physical Metallurgy Division, PMD Indira Gandhi Centre for Atomic Research
Kalpakkam – 603 102, India
Processing Scheme
Machining Mult. Pass CW
Extr. Rods Mother Tubes Int. Heat Trtmt. Clad Tubes
Courtesy: IGCAR ODS Task force, ARCI - Hyderabad
22 July 2008 4
WS&FT-08
Physical Metallurgy Division, PMD Indira Gandhi Centre for Atomic Research
Kalpakkam – 603 102, India
Importance of Microstructural & Microchemical
Investigations MA systems
• Grain morphology
• Phase stability
• Microstructural Uniformity
• Mechanical Interdiffusion
(Microchemical Uniformity) Milling process
Dispersoid Large strain fields +
• Shape Subsequent Annealing Steps
• Size
• Distribution
• Interface with matrix
• Dislocations, other defects
Impurities Microstr. Mech. Prop. Purity of feed powders, containers,
• Microstructure / Microchemistry milling conditions
22 July 2008 5
WS&FT-08
Physical Metallurgy Division, PMD Indira Gandhi Centre for Atomic Research
Kalpakkam – 603 102, India
Samples Studied
#ODS 0: 48h Milled Fe-0.2Ti-0.35Y2O3 Powder
#ODS 1: Fe-0.35Y2O3
Fe (150µm) and Y2O3 (1.33µm) ball milled / 30h, annealed at 973K /
vacuum , double compacted, double sintered at 1323K / H2
#ODS 2: Fe-0.2Ti-0.35Y2O3
Fe (150µm), Ti (105µm) and Y2O3 (1.33µm) ball milled / 30h, annealed at
973K / vac., double compacted, double sintered at 1323K / H2
#ODS 3: Fe-0.2Ti-0.35Y2O3 - Forged
Fe (150µm), Ti (105µm) and Y2O3 (10-20nm) attritor milled / 20h, degassed
at 723K & sealed. Can hipped/ forged at 1323K/ 1000MPa
#ODS 4: Fe-0.12C-9Cr-2W-0.2Ti – Pre-alloyed Powder – SEM Only
#ODS 5: Yttria Powder
#ODS 6: Fe-9Cr-2W-0.2Ti-0.35Y2O3-0.12C – Milled Powder
#ODS 7: Fe-9Cr-2W-0.2Ti-0.35Y2O3-0.12C – Extruded at 1050oC
B1-ODS-S150-Z04-C46-D04-E1050-ER09
22 July 2008 6
WS&FT-08
Physical Metallurgy Division, PMD Indira Gandhi Centre for Atomic Research
Kalpakkam – 603 102, India
Samples Studied
#ODS 0: 48h Milled Fe-0.2Ti-0.35Y2O3 Powder
#ODS 1: Fe-0.35Y2O3
Fe (150µm) and Y2O3 (1.33µm) ball milled / 30h, annealed at 973K /
vacuum , double compacted, double sintered at 1323K / H2
#ODS 2: Fe-0.2Ti-0.35Y2O3
Fe (150µm), Ti (105µm) and Y2O3 (1.33µm) ball milled / 30h, annealed at
973K / vac., double compacted, double sintered at 1323K / H2
#ODS 3: Fe-0.2Ti-0.35Y2O3 - Forged
Fe (150µm), Ti (105µm) and Y2O3 (10-20nm) attritor milled / 20h, degassed
at 723K & sealed. Can hipped/ forged at 1323K/ 1000MPa
#ODS 4: Fe-0.12C-9Cr-2W-0.2Ti – Pre-alloyed Powder – SEM Only
#ODS 5: Yttria Powder
#ODS 6: Fe-9Cr-2W-0.2Ti-0.35Y2O3-0.12C – Milled Powder
#ODS 7: Fe-9Cr-2W-0.2Ti-0.35Y2O3-0.12C – Extruded at 1050oC
B1-ODS-S150-Z04-C46-D04-E1050-ER09
22 July 2008 7
WS&FT-08
Physical Metallurgy Division, PMD Indira Gandhi Centre for Atomic Research
Kalpakkam – 603 102, India
22 July 2008 8
WS&FT-08
Physical Metallurgy Division, PMD Indira Gandhi Centre for Atomic Research
Kalpakkam – 603 102, India
3 size ranges:
(a) large, facetted
(Fe-Co)
(b) 50 – 75 nm
(Fe-Ti)
(c) sub-10 nm (Fe)
Co
Fe
Courtesy:
Institute Nano-
science Initiative
IISc, Bangalore
- Tecnai F-30
22 July 2008 9
WS&FT-08
Physical Metallurgy Division, PMD Indira Gandhi Centre for Atomic Research
Kalpakkam – 603 102, India
Samples Studied
#ODS 0: 48h Milled Fe-0.2Ti-0.35Y2O3 Powder
#ODS 1: Fe-0.35Y2O3
Fe (150µm) and Y2O3 (1.33µm) ball milled / 30h, annealed at 973K /
vacuum , double compacted, double sintered at 1323K / H2
#ODS 2: Fe-0.2Ti-0.35Y2O3
Fe (150µm), Ti (105µm) and Y2O3 (1.33µm) ball milled / 30h, annealed at
973K / vac., double compacted, double sintered at 1323K / H2
#ODS 3: Fe-0.2Ti-0.35Y2O3 - Forged
Fe (150µm), Ti (105µm) and Y2O3 (10-20nm) attritor milled / 20h, degassed
at 723K & sealed. Can hipped/ forged at 1323K/ 1000MPa
#ODS 4: Fe-0.12C-9Cr-2W-0.2Ti – Pre-alloyed Powder – SEM Only
#ODS 5: Yttria Powder
#ODS 6: Fe-9Cr-2W-0.2Ti-0.35Y2O3-0.12C – Milled Powder
#ODS 7: Fe-9Cr-2W-0.2Ti-0.35Y2O3-0.12C – Extruded at 1050oC
B1-ODS-S150-Z04-C46-D04-E1050-ER09
22 July 2008 10
WS&FT-08
Physical Metallurgy Division, PMD Indira Gandhi Centre for Atomic Research
Kalpakkam – 603 102, India
Counts (arb.un.) FeEsc Cr k
Fe k
Fe k
Cr k
Ni k
1 2 3 4 5 6 7 8
Energy (keV)
22 July 2008 11
WS&FT-08
Physical Metallurgy Division, PMD Indira Gandhi Centre for Atomic Research
Kalpakkam – 603 102, India
Samples Studied
#ODS 0: 48h Milled Fe-0.2Ti-0.35Y2O3 Powder
#ODS 1: Fe-0.35Y2O3
Fe (150µm) and Y2O3 (1.33µm) ball milled / 30h, annealed at 973K /
vacuum , double compacted, double sintered at 1323K / H2
#ODS 2: Fe-0.2Ti-0.35Y2O3
Fe (150µm), Ti (105µm) and Y2O3 (1.33µm) ball milled / 30h, annealed at
973K / vac., double compacted, double sintered at 1323K / H2
#ODS 3: Fe-0.2Ti-0.35Y2O3 - Forged
Fe (150µm), Ti (105µm) and Y2O3 (10-20nm) attritor milled / 20h, degassed
at 723K & sealed. Can hipped/ forged at 1323K/ 1000MPa
#ODS 4: Fe-0.12C-9Cr-2W-0.2Ti – Pre-alloyed Powder – SEM Only
#ODS 5: Yttria Powder
#ODS 6: Fe-9Cr-2W-0.2Ti-0.35Y2O3-0.12C – Milled Powder
#ODS 7: Fe-9Cr-2W-0.2Ti-0.35Y2O3-0.12C – Extruded at 1050oC
B1-ODS-S150-Z04-C46-D04-E1050-ER09
22 July 2008 12
WS&FT-08
Physical Metallurgy Division, PMD Indira Gandhi Centre for Atomic Research
Kalpakkam – 603 102, India
Ti k
FeEsc Cr k
Counts (arb.un.)
Cr k
Al k
Ni k
Fe k
Fe k
1 2 3 4 5 6 7 8
Energy (keV)
22 July 2008 13
WS&FT-08
Physical Metallurgy Division, PMD Indira Gandhi Centre for Atomic Research
Kalpakkam – 603 102, India
Samples Studied
#ODS 0: 48h Milled Fe-0.2Ti-0.35Y2O3 Powder
#ODS 1: Fe-0.35Y2O3
Fe (150µm) and Y2O3 (1.33µm) ball milled / 30h, annealed at 973K /
vacuum , double compacted, double sintered at 1323K / H2
#ODS 2: Fe-0.2Ti-0.35Y2O3
Fe (150µm), Ti (105µm) and Y2O3 (1.33µm) ball milled / 30h, annealed at
973K / vac., double compacted, double sintered at 1323K / H2
#ODS 3: Fe-0.2Ti-0.35Y2O3 - Forged
Fe (150µm), Ti (105µm) and Y2O3 (10-20nm) attritor milled / 20h, degassed
at 723K & sealed. Can hipped/ forged at 1323K/ 1000MPa
#ODS 4: Fe-0.12C-9Cr-2W-0.2Ti – Pre-alloyed Powder – SEM Only
#ODS 5: Yttria Powder
#ODS 6: Fe-9Cr-2W-0.2Ti-0.35Y2O3-0.12C – Milled Powder
#ODS 7: Fe-9Cr-2W-0.2Ti-0.35Y2O3-0.12C – Extruded at 1050oC
B1-ODS-S150-Z04-C46-D04-E1050-ER09
22 July 2008 14
WS&FT-08
Physical Metallurgy Division, PMD Indira Gandhi Centre for Atomic Research
Kalpakkam – 603 102, India
140
Pore Size Distribution
120
Frequency
100
80
60 Porosity ~ 1%
40
20
0
2 4 8 More
Pore dia. (mm)
22 July 2008 15
WS&FT-08
Physical Metallurgy Division, PMD Indira Gandhi Centre for Atomic Research
Kalpakkam – 603 102, India
SADP
SADP Intensity Profile (arb.un.) Fe (211) Y2O3 (400)bcc/(200)fcc
Y2O3 (222)bcc/(111)fcc
Fe (200)
Fe (110)
Fe (310)
Y2O3 (622)bcc/(311)fcc
Selection Rule
Y2O3 (440)bcc/(220)fcc
FCC : (h k l) all
Fe (220)
-Fe - JCPDS # 06-0696
(a=2.866Å) odd / even
bcc - Y2O3 - JCPDS # 41-1105 BCC : h + k + l
(a=10.60) even
Fe (222)
fcc - Y2O3 - JCPDS # 43-0661
(a=5.140)
Y2O3 (211)bcc
1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0
d (Å)
22 July 2008 16
WS&FT-08
Physical Metallurgy Division, PMD Indira Gandhi Centre for Atomic Research
Kalpakkam – 603 102, India
DF
Fek 40
35
30
Counts (arb.un.)
Frequency 25
20
15
Tik 10
Fek
Yl
5
Tik Yk
0
2 4 6 8 10 12 14 16 20 30 40 50 60 70 80
Energy (keV) Size (nm)
22 July 2008 17
WS&FT-08
Physical Metallurgy Division, PMD Indira Gandhi Centre for Atomic Research
Kalpakkam – 603 102, India
IMPURITY
22 July 2008 18
WS&FT-08
Physical Metallurgy Division, PMD Indira Gandhi Centre for Atomic Research
Kalpakkam – 603 102, India
Samples Studied
#ODS 0: 48h Milled Fe-0.2Ti-0.35Y2O3 Powder
#ODS 1: Fe-0.35Y2O3
Fe (150µm) and Y2O3 (1.33µm) ball milled / 30h, annealed at 973K /
vacuum , double compacted, double sintered at 1323K / H2
#ODS 2: Fe-0.2Ti-0.35Y2O3
Fe (150µm), Ti (105µm) and Y2O3 (1.33µm) ball milled / 30h, annealed at
973K / vac., double compacted, double sintered at 1323K / H2
#ODS 3: Fe-0.2Ti-0.35Y2O3 - Forged
Fe (150µm), Ti (105µm) and Y2O3 (10-20nm) attritor milled / 20h, degassed
at 723K & sealed. Can hipped/ forged at 1323K/ 1000MPa
#ODS 4: Fe-0.12C-9Cr-2W-0.2Ti – Pre-alloyed Powder – SEM Only
#ODS 5: Yttria Powder
#ODS 6: Fe-9Cr-2W-0.2Ti-0.35Y2O3-0.12C – Milled Powder
#ODS 7: Fe-9Cr-2W-0.2Ti-0.35Y2O3-0.12C – Extruded at 1050oC
B1-ODS-S150-Z04-C46-D04-E1050-ER09
22 July 2008 19
WS&FT-08
Physical Metallurgy Division, PMD Indira Gandhi Centre for Atomic Research
Kalpakkam – 603 102, India
FeK
CrK
Counts
CrK FeK
TiK
W L
3 4 5 6 7 8 9 10
Energy (keV)
Element Wt. %
Ti 0.57
Cr 9.78
Fe 87.18
W 2.46
22 July 2008 20
WS&FT-08
Physical Metallurgy Division, PMD Indira Gandhi Centre for Atomic Research
Kalpakkam – 603 102, India
Samples Studied
#ODS 0: 48h Milled Fe-0.2Ti-0.35Y2O3 Powder
#ODS 1: Fe-0.35Y2O3
Fe (150µm) and Y2O3 (1.33µm) ball milled / 30h, annealed at 973K /
vacuum , double compacted, double sintered at 1323K / H2
#ODS 2: Fe-0.2Ti-0.35Y2O3
Fe (150µm), Ti (105µm) and Y2O3 (1.33µm) ball milled / 30h, annealed at
973K / vac., double compacted, double sintered at 1323K / H2
#ODS 3: Fe-0.2Ti-0.35Y2O3 - Forged
Fe (150µm), Ti (105µm) and Y2O3 (10-20nm) attritor milled / 20h, degassed
at 723K & sealed. Can hipped/ forged at 1323K/ 1000MPa
#ODS 4: Fe-9Cr-2W-0.2Ti – Pre-alloyed Powder – SEM Only
#ODS 5: Yttria Powder
#ODS 6: Fe-9Cr-2W-0.2Ti-0.35Y2O3-0.16C – Milled Powder
#ODS 7: Fe-9Cr-2W-0.2Ti-0.35Y2O3-0.16C – Extruded at 1050oC
B1-ODS-S150-Z04-C46-D04-E1050-ER09
22 July 2008 21
WS&FT-08
Physical Metallurgy Division, PMD Indira Gandhi Centre for Atomic Research
Kalpakkam – 603 102, India
YL EDS: Yttria Powder, as received
Counts (arb.un.)
OK
YK
YK
1 2 3 14 15 16 17 18 19 20
Energy (keV)
Av. Particle Size (XRD) : 42 nm
22 July 2008 22
WS&FT-08
Physical Metallurgy Division, PMD Indira Gandhi Centre for Atomic Research
Kalpakkam – 603 102, India
Samples Studied
#ODS 0: 48h Milled Fe-0.2Ti-0.35Y2O3 Powder
#ODS 1: Fe-0.35Y2O3
Fe (150µm) and Y2O3 (1.33µm) ball milled / 30h, annealed at 973K /
vacuum , double compacted, double sintered at 1323K / H2
#ODS 2: Fe-0.2Ti-0.35Y2O3
Fe (150µm), Ti (105µm) and Y2O3 (1.33µm) ball milled / 30h, annealed at
973K / vac., double compacted, double sintered at 1323K / H2
#ODS 3: Fe-0.2Ti-0.35Y2O3 - Forged
Fe (150µm), Ti (105µm) and Y2O3 (10-20nm) attritor milled / 20h, degassed
at 723K & sealed. Can hipped/ forged at 1323K/ 1000MPa
#ODS 4: Fe-0.12C-9Cr-2W-0.2Ti – Pre-alloyed Powder – SEM Only
#ODS 5: Yttria Powder
#ODS 6: Fe-9Cr-2W-0.2Ti-0.35Y2O3-0.12C – Milled Powder
#ODS 7: Fe-9Cr-2W-0.2Ti-0.35Y2O3-0.12C – Extruded at 1050oC
B1-ODS-S150-Z04-C46-D04-E1050-ER09
22 July 2008 23
WS&FT-08
Physical Metallurgy Division, PMD Indira Gandhi Centre for Atomic Research
Kalpakkam – 603 102, India
22 July 2008 24
WS&FT-08
Physical Metallurgy Division, PMD Indira Gandhi Centre for Atomic Research
Kalpakkam – 603 102, India
Samples Studied
#ODS 0: 48h Milled Fe-0.2Ti-0.35Y2O3 Powder
#ODS 1: Fe-0.35Y2O3
Fe (150µm) and Y2O3 (1.33µm) ball milled / 30h, annealed at 973K /
vacuum , double compacted, double sintered at 1323K / H2
#ODS 2: Fe-0.2Ti-0.35Y2O3
Fe (150µm), Ti (105µm) and Y2O3 (1.33µm) ball milled / 30h, annealed at
973K / vac., double compacted, double sintered at 1323K / H2
#ODS 3: Fe-0.2Ti-0.35Y2O3 - Forged
Fe (150µm), Ti (105µm) and Y2O3 (10-20nm) attritor milled / 20h, degassed
at 723K & sealed. Can hipped/ forged at 1323K/ 1000MPa
#ODS 4: Fe-0.12C-9Cr-2W-0.2Ti – Pre-alloyed Powder – SEM Only
#ODS 5: Yttria Powder
#ODS 6: Fe-9Cr-2W-0.2Ti-0.35Y2O3-0.12C – Milled Powder
#ODS 7: Fe-9Cr-2W-0.2Ti-0.35Y2O3-0.12C – Extruded at 1050oC
B1-ODS-S150-Z04-C46-D04-E1050-ER09
22 July 2008 25
WS&FT-08
Physical Metallurgy Division, PMD Indira Gandhi Centre for Atomic Research
Kalpakkam – 603 102, India
Pore Density ~0.3% aligned
along Extrusion direction Tears
22 July 2008 26
WS&FT-08
Physical Metallurgy Division, PMD Indira Gandhi Centre for Atomic Research
Kalpakkam – 603 102, India
FeK-
CrK-
Y L : 0.63 %
FeK-
Ti K : 0.36 %
Cr K : 8.95 %
Intensity (au.)
Fe K : 87.6 %
W L : 2.44 %
CrK-
WM-
NiK-
YL- TiK-
WL-
2 4 6 8 10
Energy (keV)
22 July 2008 27
WS&FT-08
Physical Metallurgy Division, PMD Indira Gandhi Centre for Atomic Research
Kalpakkam – 603 102, India
Fe (110)
SADP Intensity Profile (arb.un.)
Fe (211)
Fe (200)
Y2O3 (400)bcc
Fe (310)
Y2O3 (222)bcc
Fe (220)
0
1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0
d (Å)
22 July 2008 28
WS&FT-08
Physical Metallurgy Division, PMD Indira Gandhi Centre for Atomic Research
Kalpakkam – 603 102, India
Summary
Seven sets of model materials studied (powders, milled, compacted products)
Higher Milling Duration Agglomeration
The sintered products were porous, 14-20% but forged material had a
porosity ~1%. Extruded material had porosity ~0.3% only!
Yttria bcc with a=10.6 Å
Forged sample fine bcc yttria particles with an av. size ~ 10-20 nm; some
were ~ 5-7 nm and some were agglomerated; there appeared to be an
orientation between the Yttria and the rextallised ferrite grains
Prealloyed powder & yttria powder desired sizes + quite pure
The extruded ODS steel desired composition, fine martensite laths (~100
nm wide) within the elongated grains, very fine (~ 3nm) yttria.
22 July 2008 29
WS&FT-08
Physical Metallurgy Division, PMD Indira Gandhi Centre for Atomic Research
Kalpakkam – 603 102, India
Contributors
IGCAR, Kalpakkam ARCI, Hyderabad
Arup Dasgupta*, R Vijay, S
R Divakar, S Saroja, Sudhakara Sarma, A
E Mohandas, Venugopala Reddy
M Vijayalakshmi,
PV Sivaprasad,
KBS Rao &
Baldev Raj
22 July 2008 30
WS&FT-08