Transcript Phase Separation in Magnetic Oxides: Mesoscopic vs

Dubna material studies activity
in the frame of IAEA and ISTC research projects
Anatoly Balagurov
[email protected]
Danas Ridikas
[email protected]
Frank Laboratory of Neutron Physics
Joint Institute for Nuclear Research
Dubna, Moscow reg.
Physics Section,
Division of Physical and Chemical Sciences
Department of Nuclear Applications and Science
IAEA, Vienna

High-resolution neutron diffraction

Strain – Size effects in diffraction patterns

IAEA activity: Coordinated Research Projects

ISTC activity: Research Project

Collaboration with JINR Member States
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Neutron diffraction for material science
Crystal structure:
- crystal lattice
- crystal symmetry
- atomic coordinates
- thermal parameters
- occupancy factors
Local structure:
- local distortions
- local correlations
- local disorder
Magnetic structure:
- magnetic lattice
- magnetic symmetry
- magnetic moments values
- magnetic moments direction
Microstructure:
- phase composition
- crystallographic texture
- macrostresses
- size & strain effects
- structural defects
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High-resolution diffraction for peak shift and broadening effects
I. Macrostress → Peak shift = a/a = /E
fe-str-1
-Fe
(110)
(a-a0)/a0=0.001
(200 MPa)
(a-a0)/a0=-0.0001
(20 MPa)
For min = 20 MPa and E ≈ 20·1010 Pa = 200 GPa (steel)
we need in a/a ≈ 0.001
2.020
2.025
2.030
2.035
d, Å
II. Peak broadening effects:
Microstresses → a/a ≈ Const ≈ 0.001
Size effect → d/d = d/2πWx
d ≈ 2 Å, Wx ≈ 300 Å,
Δd/d ≈ 0.001
Very high resolution, R ≈ 0.001 or better, is needed!
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High-resolution neutron powder diffraction
Continuous Sources:
Short Pulse Sources:
Long Pulse Sources:
ILL, FRM-II, SINQ, …
ISIS, SNS, J-SNS, …
IBR-2, ESS, …
W = 10 – 100 MW
Δt0 = ∞
W = 0.1 – 1.2 MW
Δt0 ≈ (15 – 30)∙λ μs
W = 2 – 5 MW
Δt0 ≈ (300 – 1500) μs
λ = const
diffractometer
- λ ≈ 1.9 Å
- Monochromator
take-off angle ≈ 120º
TOF
diffractometer
Long FP: L ≈ 100 m
or fast chopper
(Fermi / Fourier)
- λ ≈ 0.5 - 4 Å
- Flight-pass ≥ 20 m
Neutron pulse after fast
chopper Δt0 ≈ (10 – 50) μs
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Resolution of TOF-diffractometer
R(t, θ) = d/d = [(t0/t)2 + (θ/tgθ)2]1/2
t ~ L·sinθ,
R0
if
t0  0 or L  
and
θ  0 or θ  /2
0.006
TOF_Resolut-11
0.005
HRPT (SINQ)
= 1.15 Å
d/d
0.004
TOF-diffractometer:
d/d ≈ const ≈ 0.001
for d > 2 Å.
0.003
0.002
HRFD,(IBR-2)
TOF, 20 m (IBR-2)
HRFD
0.001
HRPD (ISIS)
HRPD,
TOF, 100 m (ISIS)
0
0
1
2
d, Å
3
4
5
NAC standard (Na2Al2Ca3F14) on TOF and λ0 diffractometers
nac-6000-2_4
HRFD
NAC
nac-hrpt-2_4
Intensity
Normalized intensity
HRPT
NAC, =1.886 Å
0.8
1.0
1.2
1.4
1.6
1.8
2.0
2.2
d, Å
HRFD (TOF): 2θ0=152, λ=1.2–7.2 Å
2.4
0.8
1.0
1.2
1.4
1.6
1.8
2.0
2.2
2.4
d, Å
HRPT (λ0): λ0=1.886 Å, 2θ=10-165
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Neutron spectrometers on the IBR-2M reactor
Diffraction (6):
HRFD, DN-2, SKAT, EPSILON,
FSD, DN-6
SANS (2):
YuMO, SANS-C
Polarized neutron reflectometry (3):
REMUR, REFLEX, GRAINS
Inelastic scattering (2):
NERA, DIN
13 spectrometers (3 new)
3 cold moderators (new)
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TOF diffractometers at the IBR-2M
1. HRFD – high resolution Fourier diffractometer
crystal structure of powders, anisotropic broadening
2. DN-2 – multi-purpose diffractometer
single crystals, magnetic structures, real-time studies
3. DN-12 (DN-6) – diffractometer for microsamples
high pressure experiments
4. FSD – Fourier (RTOF) stress diffractometer
internal stresses in bulk samples
5. EPSILON – TOF stress diffractometer
internal stresses in bulk samples
6. SKAT – texture diffractometer
texture of rocks and bulk samples
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Diffraction at the IBR-2M. Resolution.
0.1
TOF_Resolut_Com
Resolution, d/d
DN-2/DN-6
0.01
SKAT/EPSILON
FSD
HRFD powders, stresses
FSD
stresses
DN-2
real-time, multilayers
DN-6
high-pressure
EPSILON stresses
SCAT
textures
HRFD
0.001
Resolution becomes better
for longer d-spacing!
0.0001
0
1
2
3
4
5
6
7
8
d, Å
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HRFD – High Resolution Fourier Diffractometer at IBR-2
tof-rtof
IBR-2, TOF
W = 350 s
R = 0.01
Put into regular operation in 1994
by collaboration:
FLNP (Dubna), PNPI (Gatchina),
IBR-2, RTOF
W = 10 s
R = 0.0007
-300
-200
-100
0
t, s
100
200
300
VTT (Espoo), IzfP (Dresden).
HRFD (Dubna):
<2θ> = 152º
t0 = const  10 s
L  21 m
d/d ≈ const ≈ 0.001
for d > 2 Å
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Fast Fourier chopper at HRFD (Dubna)
Rotor
0.7 mm
Stator
Dubna chopper:
Al-alloy
 = 50 cm
N = 1024
<d> = 0.7 mm
7.5 kW motor
Triangular chopper
transmission function:
T(t) ~ 1 + sin ωt
Vmax = 6000 rpm
Ω = 100 kHz
Δt0 = 10 μs
Transmission = 0.25
Binary pick-up signals
for RTOF analyzer
Sbeam = 3x30 cm2
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Rietveld analysis of the HRFD data (MRIA package)
Normalized neutron counts
nac-1r
Na2Al2Ca3F14
HRFD
0.7
0.8
0.8
1.0
0.9
1.0
5
0
-5
1.2
1.4
1.6
1.8
2.0
2.2
2.4
d, Å
Diffraction pattern obtained with NAC-standard, Δd/d ≈ 0.001
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HRFD: detectors around sample position
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“Size” and “strain” broadening of diffraction lines
W2 = C1 + C2d 2 + C3d 2 + C4d 4
Size of domains,
C4 ~ (1/L)2
Microstresses,
C3 = (a/a)2
Resolution function of
TOF-diffractometer
300
80
wid_d-1
CaCuMn6O12
wid_al2o3_NAC
HRFD
HRFD
250
Ca-800
60
800
40
W2, arb. un.
Al2O3 (chw=4 s)
(Sep-04, 823)
W2
200
NAC (chw=4 s)
(Dec-04, 916)
W**2
W2 = C1 + C2d2 + C3d4
1000
Ca-950
150
100
Ni
600
400
Al2O3
20
200
50
Al2O3
0
0
0
2
4
d**2
6
W2(d 2) function for NAC and
Al2O3 standard samples
wid-Ni-3
0
0
2
4
6
8
d2
Microstresses in CaCuMn6O12
for two temperatures
0
1
2
3
4
(d, Å)2
Peak width for nanosized Ni
with <D> ≈ 380 Å.
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Applied researches at the IBR-2
steel
A part of the real VVER-1000 vessel
(built-up welding stainless steel)
Zr
Cross-section of the bimetallic steel-zirconium adapter
D24 mm
incident beam
5 mm
30 mm
D8 mm
2 mm
162 mm
Qrad
56 mm
scattered beam(2 x 5 mm)
Biaxially fatigued stainless steel
sample of cruciform geometry
Perforator’s striker
IAEA project D2.01
Enhancement of research reactor (RR) utilization and applications
List of major activities:

RR coalitions & networks

Research Reactor Data Base (RRDB)

Coordinated Research Projects

Technical (TM) and Consultancy (CM) Meetings

International RR Conference, Workshops, Schools

Support of national & regional TC projects

Publications, technical reports, brochures
More information available at:
http://www-naweb.iaea.org/napc/physics/research_reactors
16
New RRDB capability: utilization & applications oriented
Available at:
http://www-naweb.iaea.org/napc/physics/research_reactors/
or USB Memory Stick, <10MB, no internet is needed!
New RRDB capability: utilization & applications oriented
44 RRs employ neutron beams; they are distributed over 30 MSs
Available at:
http://www-naweb.iaea.org/napc/physics/research_reactors/
or USB Memory Stick, <10MB, no internet is needed!
IAEA activity: Coordinated Research Projects
CRP 1314 (2006-2009): Development and application of the techniques of
residual stress measurements in materials
Objectives:
 characterization, tests and development of materials
 development of new instruments & upgrade of existing facilities
 advanced analysis of material stresses – links to industrial partners
 harmonisation and standardization procedures (e.g. round robin experiment)
 5 Research Contracts + 4 Research Agreements
1.
2.
3.
4.
5.
6.
7.
8.
9.
Czech Republic
Germany
Hungary
India
The Netherlands
Pakistan
Romania
Russian Federation
South Africa
Main achievements/outlook:
 Creation of network on residual stress
 Transfer of know-how from RA holders to RC (developed  developing)
 Round Robin experiments are ongoing (+USA, +Australia, +UK)
 Project report for Technical Report Series is in preparation
Application of Reverse Time of Flight (RTOF) Neutron
Diffraction for Residual Stress Investigations
The main tasks of the project were devoted to modernization of
the main units of FSD diffractometer:
1) Installation of new detector modules;
2) Precise sample alignment system improvement;
3) Adaptation of the new mechanical testing machine for
tensile/compressive test with force and temperature control.
90º-detector system based on ZnS(Ag)
scintillator with wavelength-shifting fibers
FSD diffractometer
Backscattering
detector
Status of the detector system:
Six modules of ZnS(Ag) +90°
(on the left) and -90° (on the
right) detectors are currently
installed on FSD.
Two new modules are in
preparation.
90º-detector
Sample position
Neutron guide
IAEA activity: Coordinated Research Projects
Active CRP 1575 (2009-2012): Development, Characterization and Testing of
Materials of Relevance to Nuclear Energy Sector Using Neutron Beams
(SANS, diffraction and neutron radiography)
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
Objectives:
investigation and characterization of materials relevant to nuclear energy applications
optimization and validation of experimental and modeling methods
creation of a database of reference data for nuclear materials research
enhancement of the capacity of research reactors for nuclear materials research
 8 Research Contracts + 9 Research Agreements
Argentina
Australia
Brazil
China
Czech Republic
France
Germany
Hungary
Indonesia
Italy
Japan
Korea
The Netherlands
Romania
Russian Federation
Switzerland
USA
Expected output:
Materials characterized, experimental/modelling methods optimized
Creation of multilateral network in the field of advanced nuclear materials research
Creation of an experimental reference database for models and calculations
Final project publication
Ferrite-Martensite Steels Dispersion Hardening Studied by
TOF Neutron Diffraction
Scientific scope of the project:
Relation between dispersion-hardening particle size and microstress value in steel.
The influence of these parameters on strength characteristics of steels at various
temperatures.
Subject of studies:
High-strength dual-phase ferrite - martensite steels (soft ferrite matrix containing
islands of martensite) with dispersion-hardened phases: Fe-12%Cr matrix +
V/Mo/Nb carbides (EP-450), V/W/Nb nitrides (EP-900), EP-450 ODS (oxide
dispersion strengthened by Y2O3).
Experimental technique:
High-resolution TOF neutron diffraction with high-temperature in situ loading.
23
Five main topics to be addressed:
1.
Utilization & Applications of RRs
2.
Operation & Maintenance
3.
New RR Projects
4.
Safety of RRs
5.
Spent Fuel Management, Waste &
Decommissioning
Jointly by NA, NE, NS and TC
Contact: D. [email protected]
24
ISTC project № 3074.2
Neutron-Diffraction Study of Micro- and Macrostresses in Structural Ageing
Alloys for Nuclear Power Engineering after Thermal and Radiation
Exposure and Predicting Resistance to Radiation-Induced Swelling
Participants:
Institute of Metal Physics, Yekaterinburg
Joint Institute of Nuclear Research, Dubna
Institute of Technical Physics, Snezhinsk
Period of realization:
September, 2008 – February, 2011 (30 months)
Budget:
$253,229 Euro
Foreign Experts:
Dr. Rainer Schneider, Berlin
Dr. Carsten Ohms, Petten
Dr. Pavol Mikula, Prague
ISTC project № 3074.2
First task: microstresses in the bulk of the components from radiation-resistant
ageing alloys in the course of formation, growth and coagulation of the second-phase
disperse particles. Steels with coherent Ni3Ti intermetallic precipitates, semicoherent and incoherent VC carbides will be studied.
Second task: analysis of microstresses around defect clusters formed in place of
displacement cascades under neutron irradiation.
Third task: investigation of residual macro- and microstresses arising as a result of
phase and structural transformations in steel and alloys, predominantly in the
thermally affected zone of weld seams of large-diameter pipes.
Austenitic steel Fe0.748Mn0.179V0.013Cr0.042C0.018
with VC precipitates
Three samples have been studied after quenching
from 1100ºC: initial, annealed at 600оС and 700оС.
Annealing time was 1, 6, and 12 hours.
Alloy-3-1
Fe0.748Mn0.179V0.013Cr0.042C0.018
600oC
3.612
a, Å
2500
3.614
The lattice parameter
dependence for
40Х4Г18Ф steel vs.
annealing time at two
temperatures:
600оС and 700оС.
3.61
700oC
Ini
3.608
2000
Intensity
3.606
40x4-par
600oC
1500
3.604
0
700oC
5
10
Annealing time, hours
12
1000
40x4-strain
700oC
8
Strain, a/a*104
500
0
126
128
130
132
134
Scattering angle
136
4
138
Comparison of diffraction patterns for
40Х4Г18Ф steel samples: initial and aged at
600оС and 700оС in 12 hours.
The strain (Δa/a)
dependence for
40Х4Г18Ф steel vs.
annealing time at two
temperatures:
600оС and 700оС.
600oC
0
0
5
10
Annealing time, hours
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Investigation of the atomic and magnetic structures of crystals
and internal stresses in bulk materials and components
In the frame of JINR – NECSA project: “Neutron Scattering Applications”
Co-ordinator from JINR:
Dr. Anatoly M. Balagurov
Co-ordinator from NECSA (South Africa):
Dr. Anrew M. Venter
1. Instruments development
2. Joint experiments:
“Stresses in biaxially fatigued stainless steel sample of cruciform geometry”
“Residual stresses in a stainless steel-Ti(Nb) bimetallic tube adapter”
Joint experiment in 2009/2010
“Residual stresses in biaxially fatigued stainless steel sample of cruciform
geometry” SALSA (ILL, France) & POLDI (PSI, Switzerland
Metastable austenitic stainless steel AISI 321 were subjected to the in-plane biaxial tensioncompression fatigue cycling on the INSTRON planar biaxial loading machine at FIMS (Bremen).
Residual stresses in to the ex-situ in-plane biaxial low cycle fatigued sample of the cruciform
geometry from AISI 321 were measured at SALSA (ILL) and POLDI (PSI) instruments.
(211) martensite
Spectra from the martensite
(left side) and austenite (right
side) in the Krest-2 sample
measured on the SALSA.
Vg = 0.5 mm3
texp= 20 to 35 min.
(220) austenite
Biaxially fatigued stainless steel sample
of cruciform geometry at POLDI (SINQ
neutron source, PSI).
29
Joint experiments in 2010/2011
“Residual stresses in a stainless steel-titanium/niobium bimetallic tube adapter”
POLDI diffractometer at SINQ, PSI (Villigen, Switzerland)
Stainless steel-titanium bimetallic tube adapters are being considered for use in superconducting
radiofrequency cavities. Hermetic welding of the adapter is achieved by explosive bonding
method. The residual stresses into the adapter are of large practical interest for the
improvement of explosive welding technology and minimization of the production cost.
Bimetallic tube is placed at the POLDI
diffractometer, SINQ neutron source, PSI.
A set of samples are prepared for investigation
of residual stresses in bimetallic joining.
30
User program at the IBR-2M spectrometers
Time-sharing (13 spectrometers)
FLNP (35%)
International experts’
commissions:
External
fast (10%)
External
regular (55%)
I. Diffraction
II. Inelastic Scattering
III. Polarized neutrons
IV. SANS
User statistics
Others, 19%
FLNP, 25%
France, 3%
Poland,
5%
Germany,
17%
Russia, 31%
You are invited for experiments at the IBR-2M reactor
in Dubna – a nice place at the Volga River
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