Ex-situ and in-situ studies of radiation damage mechanisms ... · Fresnel contrast (±500 nm) bright field TEM images from 2000-day autoclave-corroded samples and 2700-day in-reactor

ASTM 19th International Symposium on Zirconium in the Nuclear Industry

Ex-situ and in-situ studies of radiation damage

mechanisms in Zr-Nb alloys

Junliang Liu1, Guanze He1, Anne Callow1, Kexue Li1, Sergio Lozano-

Perez1, Angus Wilkinson1, Michael Moody1, Chris Grovenor*1,Jing Hu2,

Mark Kirk2, Meimei Li2, Anamul Haq Mir3, Jonathan Hinks3, Stephen

Donnelly3, Jonna Partezana4 and Heidi Nordin5

1 Department of Materials, Oxford University, Oxford, UK.2 Argonne National Laboratory, Argonne, IL, US3 School of Computing and Engineering, University of Huddersfield, UK4 Westinghouse Electric Company, Pittsburgh, PA, US5 Canadian Nuclear Laboratories, Chalk River, ON, K0J 1J0 Canada

1

2

What are we interested in?The use of advanced analytical techniques to study the response of Zr cladding materials to corrosion and radiation damage

J. Hu et al. Acta Materialia May 2nd 2019 https://doi.org/10.1016/j.actamat.2019.04.055

Materials

Autoclave corrosion:

Zircaloy-4 and Zr-0.5Nb: 360°C,

18MPa, Pure water

Zr-2.5Nb: 300°C, 10 Mpa, D2O,

PH=10.5(LiOD)3

Materials

CNL Halden reactor

samples

• In-flux

• Out-of-flux but in-reactor

water chemistry

• Static autoclave with D2O

(pH=10.5, LiOD), and at

300°C and 10 MPa.

• In flux 325 oC samples that

have been extensively

analysed

4

20 µm

2 µm

Zr-1Nb sheet

SRA Zr-2.5Nb tube

AD

RD*

TD*

RD

TD

ND

Materials

5

Aim of study Material Conditions Sample source

In-situ heavy ion irradiation

1. Irradiation effects in Zr

oxidesRX Zr-0.5Nb

Autoclave

corrosionWestinghouse

and CNL2. Irradiation induced

elemental redistribution

RX Zr-1Nb

RX and SR

Zr-2.5Nb

Metal

Ex-situ characterisation of

in-reactor corroded alloys

3. Microstructure of in-

reactor formed oxideSR Zr-2.5Nb

In-reactor

corrosionCNL

4. Irradiation-induced

elemental redistribution

3D mapping of deuterium

distribution using

NanoSIMS

5. The transportation of

hydrogen/deuterium

through the oxide layer

Ziraloy-4

SR Zr-2.5Nb

Autoclave

and

In-reactor

Corrosion

Westinghouse

and CNL

Experiments undertaken

RX: Recrystallised; SR: Stress Relieved

6

Sample exchange

Analysis chamber

Duoplasmatro

n source

Cs+ source

Multicollection chamber

Magnetic

sector

Electron beam Electron

beamIon

beam

Ion beamSEM/FIB/EDX

3D APT

In-situ TEM STEM/EELS/EDX

NanoSIMS 50

Experimental methods

7

ExperimentTemperature

(K)Ions

Flux

(ions.cm-2.s-1)

Damage rate

(dpa/s)Facility

In-situ irradiation

in oxides

50 1 MeV Kr++ 8 x 1011 1.5x10-3 IVEM

293 700 keV Kr++ 1-5 x 1012 0.5-2.5x10-3MIAMI2

In-situ irradiation

in SPPs and

metal matrix

50 1 MeV Kr++ 8×1011 1.5x10-3 IVEM

293 1 MeV Kr++ 8×1011 1.5x10-3 IVEM

623 1 MeV Kr++ 8×1011 1.5x10-3 IVEM

873 1 MeV Kr++ 8×1011 1.5x10-3 IVEM

623 350 keV Kr++ 6×1011 1-3x10-3 MIAMI2

In-Reactor 600, 520 Neutrons 4.3-4.7×1013 ~10-7Halden

Reactor

Irradiation Parameters

8

In-situ Ion Irradiation of bulk monoclinic-ZrO2 on 0.5 %-Nb (210 days)

Evolution of oxide

structure under in

situ 700 keV Kr++

irradiation at room

temperature

9

0 dpa 3 dpa (5.6x1015 ions.cm-2) 10 dpa (1.9x1016 ions.cm-2)

700 keV Kr++ implantation at 293 K to different damage levels; pre-irradiation, 5.6x1015 ions.cm-2 (3 dpa)

and (c) 1.9x1016 ions.cm-2 (10 dpa)

In-situ Ion Irradiation damage in monoclinic-ZrO2

Simulated patterns Rotationally averaged experimental patterns

10

In-situ Ion Irradiation damage in monoclinic-ZrO2

Atomic-resolution HAADF STEM image from an oxide grain post-irradiation, 1.9x1016 ions.cm-2

(10 dpa), with corresponding FFT from the whole region, (b) direct measurement of lattice

parameters based on the HAADF STEM images11

In-situ Ion Irradiation damage in monoclinic-ZrO2

TKD pattern quality and phase maps

from typical regions of in-situ

irradiated Zr oxide.

(a and d) 0 dpa,

(b and e) 4 dpa, 7.4x1015 ions.cm-2

(c and f) 10 dpa, 1.9x1016 ions.cm-2

0 dpa 4 dpa 10 dpa

monoclinic 97.5% 10.5% 0.4%tetragonal 2.5% 4.1% 4.4%

cubic 0 85.4% 95.2%Horizontal

grain size

(nm) 63±6 66±11 97±24Vertical grain

size (nm) 142±28 76±13 162±49

12

In-situ Ion Irradiation damage in ZrO suboxide

In-situ TEM images of

suboxide region and metal

substrate in the Zr-0.5Nb

alloy: (a) pre-irradiation (b)

1014 ions/cm2

Pre-irradiation HAADF

STEM image of the region

followed during in-situ

irradiation and (d) O/Zr

atomic ratio map from EELS

analysis of the pre-irradiation

sample.

13

Preferential amorphisation of ZrO suboxide

HRTEM images and

FFTs from the

interface region

(a) pre-irradiation

(b) irradiated at 293

K to 1.9x1016

ions.cm-2

(c) irradiated at 50 K

to 4 x 1015 ions.cm-2

14

J Liu et al.Journal of Nuclear Materials 513, 226-231 2019

RTDFg, 3g

350℃BF

In-situ Ion Irradiation damage in SPPs in metal matrix

Following the same particles during in-situ irradiation

• Morphology of SPPs can easily be obscured by dislocation loops, surface oxide and

bend contours

15

In-situ Ion Irradiation damage of β-Nb SPPs in metal matrix

0002 α

ത2110 α

ത2112 α

B= 01ത10 α−Zr

01ത1 β

110 β101 β

B= ത111 β−Nb

(a) pre-irradiation BF (b) post-irradiation BF

(c) pre-irradiation SAD (d) post-irradiation SAD

EDX line-scan profiles of Nb Ka for SPPs

irradiated at 293 K, 623 K, and 873 K with 1

MeV Kr++ to 6.4x1015 ions.cm-2 (15 dpa).

Before and after irradiation by 1 MeV Kr++ to

6.4x1015 ions.cm-2 (15 dpa) at 293 K .

16

Size changes in ion-irradiated β-Nb SPPs?

-20%

-10%

0%

10%

20%

30%

40%

50%

0

10

20

30

40

50

60

50 293 623 873

Rela

tive

siz

e c

han

ge

Rad

ius

(nm

)

Irradiation temperatures (K)

β-Nb SPP size after irradiation at different temperatures

before after relative size change

0 20 40 60 80 100 120 140 160 180 200

0

50

100

150

200

250

300

350

Zr Kα1

Nb Kα1

Simulated pre NbZr

Kα

1

Distance (nm)

Post irradiation

17

In-situ Ion Irradiation damage in Lave phase SPPs in metal matrix

(c)

SPP

Zr(Nb, Fe)2

α-Zr Matrix

(a) (b)

FFT from SPP

FFT from matrix

HRTEM images and inset FFTs showing the amorphisation of a Laves phase SPP

irradiated at 50 K to 6.8x1015 ions.cm-2 (16 dpa), with EDX line-scans over the

same SPP before and after irradiation18

How can we study composition changes in the matrix?APT tips irradiated in Huddersfield MIAMI2 with 650 keVKr2+ ionsCNL B166 Zr2.5Nb

TEM Before TEM after 15 dpa

19

Metal matrix average Nbcontent of 0.42 at% (cf0.45 at% in un-irradiated material.

No Clusters detected

FeNb

Zr

ZrO2

Sample B166 Zr-2.5%Nb650 keV Kr+ 5 dpa

Zr Nb Fe Cr C O Al

98.5 0.42 0.03 0.01 0.12 0.89 0.01

Kr ion irradiation to 5 dpa

20

In flux and out of flux CNL samples have been studied to:

• Compare pore distributions between in flux and out of flux samples

• Analyse differences in oxide grain texture in autoclave and in-reactor samples

• Study the growth of nano-scale b-Nb precipitates during n-irradiation

• Analyse the rate at which Nb is oxidised in the oxide under different conditions

21

Does neutron-irradiation

damage create extra porosity

in the ZrO2?

Fresnel contrast (±500 nm) bright

field TEM images from 2000-day

autoclave-corroded samples and

2700-day in-reactor sample (1022

n.cm-2, ~8 dpa).

Grain boundary nano-porosity is

formed in both oxides (yellow

arrows) and but voids in the grain

interior only in the n-irradiated

sample (blue circles).

Autoclave In reactor ~ 8 dpa

22

Why are we interested in porosity? Because we can map directly

deuterium distributions in oxides. (See Jones et al this afternoon)

Distribution of 2H- and 18O- in a 61-day

Zircaloy-4 sample showing interconnected

pathways for deuterium.

Distributions of 2H- in a 700-day CNL

Zr-2.5Nb sample

23

K. Li et al. Applied Surface Science 464, 311-320 2019

Comparing pore distribution at different stages of oxidation

Autoclave 0.5%Nb samples after 75 and 165 days See Poster: Couet et al

24

Neutron-irradiation damage in ZrO2: grain size and shape

TKD analysis of oxides on CNL Zr-2.5Nb tubes (a) In-flux, 190 days, 7.6x1020 n.cm-2 (2

dpa), (b) Out-of-flux, 185 days, (c) autoclave, 150 days and (d) autoclave, 700 days. 25

All images taken at withB close to [11-20], g = (0002), 4-5g

Neutron induced nano-Nb precipitates

B70 B7426

B56: 250 oC, in flux, low damageNo detectible nano-Nb

B70: 325 oC, in flux , low damageSmall nano-Nb particles

B74: 325 oC, in flux , high damageLarger nano-Nb particles and numerous hydrides

Morphology of Irradiation induced nano-precipitates

~ 4.5 nm

~ 2 nm

~ 1.5 nm

B70, In flux 190 days, 325⁰C27

Material Number density(No./cm^3)

Average long axis (nm)

Average short axis (nm)

Aspect ratio

B70 1.9 dpa 1016 5 ± 1.3 2.4 ± 0.5 2.09

B74 25.2 dpa 5. 1015 8.3 ± 3.7 3 ± 0.9 2.71

Size and shape of nano-precipitates versus damage level

28

5 10 15 200

2

4

6

8

10

12

14

16

18

20

22

24

Co

unt

long axis (nm)

B74

B70

1 2 3 4 5 60

2

4

6

8

10

12

14

16

18

Co

unt

short axis (nm)

B74

B70

B62

B74

B56

B70The same CNL Haldenalloys have been analysed by APT

250 oC 190 days

250 oC 2400 days

325 oC 190 days

325 oC 2750 days

Nb

Residual b-Zr

29

B70, APT & TEM results

Nb Fe

Grain boundary

30

B74, APT & TEM results

Nb FeLine 1

EDX Nb line profile

31

Precipitate number density

Sample

Number Density (No. per cm^3)

By APT By TEM

B70 1.3 x 1017 1016

B74 4.9 x 1016 5.5 x 1015

The factor of ~ 10 between APT and TEM results suggest that the precipitates/clusters inspected by APT and

TEM bright field image are different. Only those large, incoherent precipitates got picked up by the TEM bright

field image, while all the large and small, coherent and incoherent clusters were counted by APT.

4 nm

B74: Nb and Fe do not precipitate together

32

Nb enrichment at c loops after 1.9 dpa

B70

EDX analysis of Nb segregation to c loops

33

Matrix and cluster compositions from APT

Nb in matrixat %

Fe in matrixat %

Nb in clustersat %

B166 Un-irradiated 0.45 0.07 -

B56 250 oC 190 days 0.31 0.07 77

B62 250 oC 2400 days 0.31 0.06 66

B70 325 oC 190 days 0.27 0.06 76

B74 325 oC 2750 days 0.17 0.04 73

34

2100 2200 2300 2400 2500 2600 2700

1000

2000

3000

4000

5000

6000

Nb L2

Nb L3

Zr L2

counts

Energy (eV)

Spectrum 1

Spectrum 2Zr L3

Identifying the oxidation rate of Nb in second phase particles by EELS

Edge shift of a specific edge indicates the change of oxidation state.

35

Oxide

Metal

Does the Nb oxidise at the same rate in different samples?

In particular, does more n-irradiation result in faster oxidation?

0 50 100 150 200

0

1

2

3

4

5

high damage

low damage

no damage

Nb

L3

Ed

ge

Sh

ift (

eV

)

Days in oxide for each individual Nb particles

Oxidation State of Nb in Beita Phase

• Oxidation rate of Nb in oxide: Out of flux > in flux low damage > in flux high damage

• Oxidation of Nb in β-Nb is slower than in β-Zr, so the decomposition of β-Zrresults in slower oxidation of Nb

36

Conclusions

37

• We have used in situ ion irradiation to study the stability of ZrO2 and metastable ZrO

oxide phases to high damage levels. The susceptibility of both phases to phase

changes has been shown.

• The extraordinary resistance of b-Nb SPPs to radiation damage has been confirmed

• Detailed analysis of the nano-structure of CNL 2.5% Nb samples after n-irradiation has

revealed the details of precipitation and changes in matrix chemistry during reactor

exposure.

• The oxidation rate of Nb (and so doping of the oxide phase) is remarkably slowed

down by n-irradiation.

Acknowledgements

38

• EPSRC grants (EP/K040375/1, EP/N010868/1 and EP/M018237

• access to the Culham Materials Research Facility.

• electron Physical Science Imaging Centre (ePSIC) on the Harwell campus for access

to the JEOL ARM300CF instrument.

• Access to the IVEM facilities at ANL was provided through the NSUF RTE

scheme

• Access to the MIAMI2 facilities was provided through the EPSRC UK National

Ion Beam Centre (http://www.uknibc.co.uk/).