Positron annihilation and tribological studies of nano-embedded Al-alloys

Jerzy Dryzek1,2, Krzysztof Siemek2 and Krzysztof Ziewiec3

1Institute of Physics, Opole University, ul. Oleska 48, Opole, Poland 2Institute of Nuclear Physics PAN, ul. Radzikowskiego 152, Kraków, Poland 3Pedagogical University of Cracow, ul. Podchorążych 2, Kraków, Poland

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Embedded nanoparticles of metals and alloys are an important class of nanomaterials requiring understanding. Additionally alloys with embedeed nanoparticles have important applications.

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Motivation

Over 109 bearing shells for journal

bearings are produced annually.

The Pb-Sb-Sn system (Isaac Babbit

1839) is the first triboalloys used as the

shells.

The substituted the systems Al-Sn and

Al-Pb are also applied.

The Al-based alloys are predominate in

European and Asian markets for

compact engines.

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We intend to include the positron studies for such triboalloys. We expect some new results, especialy positron localiztion at nanoparticles. However, our research interests is focused also on the subsurface zone (SZ) in the triboalloys based on Al.

-friction force,

-wear,

-subsurface zone with

defects,

-…

-emission of electrons,

-transfer of mass

between bodies.

-…

sliding

body

sample

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Plane

Introduction to positron annihilation techniques

The production procedure of the triboalloys based on aluminium

The XRD and SEM detection of nanoparticles

The results of tribological studies

Positron and microhardness studies of isochronal annealing of the

triboalloys

The subsurface zone in Al-In10 alloy

Conclusions

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Few words about positron annihilation techniques

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Positron and electron pair annihilation

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Beta+ decay of 22Na isotope; common positron source

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Doppler broadening (DB) measurement

e

e

+

-

Na22

sample

LN2

HpGe

e+

(511+ )keV

(511- )keV

90

m

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Annihilation line of defects free copper

photon energy (keV)

501 506 511 516 521

norm

aliz

ed c

ounts

1e-5

1e-4

1e-3

1e-2

Well annelad copper

background

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Annihilation line for copper after deep deformation

photon energy (keV)

501 506 511 516 521

norm

aliz

ed c

ounts

1e-5

1e-4

1e-3

1e-2

Well annelad copper copper after deep deformation

background

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The line shape parameter, S-parameter

photon energy (keV)

501 506 511 516 521

norm

aliz

ed c

ounts

1e-5

1e-4

1e-3

1e-2

Well annelad copper copper after deep deformation

S-parameter

background

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Dependency of the S-parameter versus the degree of deformation for copper

thickness reduction (%)

0 10 20 30

S-p

ara

mete

r

0.53

0.54

0.55

0.56

0.57

0.58

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Coincidence Doppler broadening (CDB) measurement

e

e

+

-

Na22

sample

HpGe

e+

(511+ )keV

(511- )keV

LN2

HpGe

LN2

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CDB spectrum of pure alumnium

photon energy (keV)

496 498 500 502 504 506 508 510 512 514 516 518 520 522 524 526

counts

1e+0

1e+1

1e+2

1e+3

1e+4

1e+5

1e+6

Aluminium

core regioncore region band region

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Positron lifetime measurement

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Al

=165 ps

bulk,perfect lattice

=248 ps

monovacancy

270 ps

divacancy

=174 ps

edge dislocation

=165 ps

interstital atom

vacancynear dislocation line

215 ps< <230 ps

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Dependency of the positron lifetime on the size of vacancy cluster in Al and Fe.

M.J. Puska, P. Lanki, R.M. Nieminen, J. Phys.:Condens Master, 1 (1989) 6081.

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Saka H, Nishikawa Y, Imura T Melting temperature of In particles embedded in an Al matrix. Philos. Mag.

A57: (1988) 895.

Sasaki K, Saka H In situ high-resolution electron microscopy observation of the melting process of In

particles embedded in an Al matrix. Philos. Mag. A63: (1991) 1207.

B. Klobes, B. Korff, O. Balarisi, P. Eich, M. Haaks, I. Kohlbach, K.Maier, R. Sottong and T E M Staab.

Defect investigations of micron sized precipitates in Al alloys, Journal of Physics: Conference Series

262 (2011) 012030.

Liu Yuan et al. Microstructures of rapidly solidified Al-In immiscible alloy. Trans. Nonferrous Met. Soc.

China. Vol. 11 (2001) 84.

J.P. Pathak and S. Mohan. Tribological behaviour of conventional Al–Sn and equivalent Al–Pb alloys

under lubrication. Bull. Mater. Sci., vol. 26, (2003), 315–320.

V. Bhattacharya, K. Chattopadhyay. Morphology and phase transformation of nanoscaled indium–tin

alloys in aluminium. Materials Science and Engineering A 375–377 (2004) 932–935.

V. Bhattacharyay, K. Chattopadhyay and P. Ayyub. Synthesis, transformation and superconductivity of

dual phaseIn–Sn alloy nanoparticles embedded in an Al matrix. Philosophical Magazine Letters, Vol.

85, (2005), 577–585.

Papers devoted to the aluminium alloys with embedded particles

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A. Singh and A. P. Tsai. Melting behaviour of lead and bismuth nano-particles in

quasicrystalline matrix - The role of interfaces. Sadhana Vol. 28, (2003) 63–80.

V. Bhattacharya, K. Chattopadhyay. Melting of multiphase nano-scaled particles embedded in Al

matrix: Case of Pb–Sn and Bi–Sn alloys. Materials Science and Engineering A 449–451

(2007) 1003–1008.

V. Bhattacharya, K. Chattopadhyay. Melting of multiphase nano-scaled particles embedded in Al

matrix: Case of Pb–Sn and Bi–Sn alloys. Scripta Mater. 44 (2001) 1677-1682

(Al-Sn) P.G. Forrester, Met Rev. 5 (1960) 507.

P. Bhattacharya, V. Bhattacharya, K. Chattopadhyay. Morphology and thermal characteristics of

nano-sized Pb–Sn inclusions in Al. J. Mater. Res., Vol. 17, No. (2002) 2875.

V. Bhattacharya, K. Chattopadhyay. Microstructure and wear behaviour of aluminium alloys

containing embedded nanoscaled lead dispersoids. Acta Materialia 52 (2004) 2293–2304

R. Schouwenaars, V.H. Jacobo, A. Ortiz. Microstructural aspects of wear in soft tribological

alloys. Wear , 263 (2007) 727–735.

R. Schouwenaars, V.H. Jacobo, A. Ortiz, Microstructural aspects of wear in soft tribological

alloys. Wear, 263 (2007) 727-735.

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Soft dispersions in a hard matrix

Significant improvement of frictional properties under mild wear conditions of

nanoscaled dispersion of Pb, In and Bi in Al. host has been observed.

V. Bhattacharya, K. Chattopadhyay. Scripta Mater. 44 (2001) 1677-1682

S.N. Tiwari, Wear. 112 (1986) 341

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The melt-spinning technique for production of binary immiscible alloys

Argon gas under pressure

melt metalsinductionheating

rotatingcopper cylinder

melt-spunribbon

v=22 m/s

Al-In10 wt%

Al-Pb10 wt%

Al-Sn5 wt%

Al-Bi10 wt%

Al-Au0.5 wt%

Al as-cast

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XRD

30 40 50 60 70 80 90

Al90In10

Al95Sn5

Al90Bi10

Al90Pb10

Aluminum

Bi 1

10

Sn

Sn

Sn

Sn

10

1S

n 2

00

Sn

00

1

In

In

In 1

01

Pb

33

1

Pb

31

1

Pb

22

0

Pb

20

0

Pb

11

1

Al 2

22

Al 3

11

Al 2

20

Al 2

00

Al 1

11

Inte

nsity

2

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a Al90In10 b) Al95Sn5

c) Al90Pb10 d) Al99.5Au0.5

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Al-In10

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Nano-scaled eutectic lead–tin and bismuth–tin alloys embedded in aluminum matrix

V. Bhattacharya, K. Chattopadhyay. Materials Science and Engineering A 449–451 (2007) 1003–1008.

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The particle size distribution

diameter (nm)

0 100 200 300 400 500 600

fraction (

%)

0

2

4

6

8

10

12

14

16

18

Al-Pb10

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bi

diameter (nm)

50 100 150 200 250 300 350 400

fraction (

%)

0

5

10

15

20

Al-Sn5

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diameter (nm)

50 100 150 200 250 300 350

fra

ctio

n (

%)

0

5

10

15

20

Al-In10

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The properties of the Al alloys

Alloy Average

particle

diameter

(nm)

Variance

(nm)

Friction

coefficient

Specific wear

rate

[10-12 m3/mN]

Vickers

microhar

dness

Positron

lifetime

(ps)

Al-In10 83 48 0.38 0.058 71.6 256.9(0.5)

Al-Sn5 108 64 0.39 0.099 41.3 253.7(0.5)

Al-Pb10 173 92 0.40 0.084 39.2 257.2(0.5)

Al-Bi10 671 374 - - - -

Al-Au0.5 - - 0.42 0.066 59.3 224.1(0.5)

Al as-cast - - 0.82 3.295 28.6 229.7(0.5)

AK12 0.46 0.066 178(1)

AK 12 (with the following composition: Si 12.0–13.5 wt.%, Cu 0.5–1.5 wt.%, Mg 1.0–1.5 wt.%,

Ni 0.5–1.5 wt.%, Mn 0.2 wt.%, Zn 0.2 wt.%, Fe 0.6 wt.%, Al. balance)

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Tribo test, pin on disc device

load

friction force

pin (rod)

measurementdevice

disc

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The specific wear rate measurements

distance (m)

0 10 20 30 40 50 60

mass loss (

mg)

0

1

2

3

4

5

Al-Au0.5

Ar-Sn5

Al-In10

A--Pb10

Al as-cast

alloys

Al as-cast

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The properties of the Al alloys

AK 12 (with the following composition: Si 12.0–13.5 wt.%, Cu 0.5–1.5 wt.%, Mg 1.0–1.5 wt.%,

Ni 0.5–1.5 wt.%, Mn 0.2 wt.%, Zn 0.2 wt.%, Fe 0.6 wt.%, Al. balance)

Alloy Average

particle

diameter

(nm)

Variance

(nm)

Friction

coefficient

Specific wear

rate

[10-12 m3/mN]

Vickers

microhar

dness

Positron

lifetime

(ps)

Al-In10 83 48 0.38 0.058 71.6 256.9(0.5)

Al-Sn5 108 64 0.39 0.099 41.3 253.7(0.5)

Al-Pb10 173 92 0.40 0.084 39.2 257.2(0.5)

Al-Bi10 671 374 - - - -

Al-Au0.5 - - 0.42 0.066 59.3 224.1(0.5)

Al as-cast - - 0.82 3.295 28.6 229.7(0.5)

AK12 0.46 0.066 178(1)

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Temperature dependences of microhardness

temperature (oC)

0 100 200 300 400 500

mic

rohard

ness (H

V)

10

20

30

40

50

60

70 Al-In10

Al-Au0.5

Al-Sn5

Al-Pb10

Al as-cast

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Temperature dependences of S-parameter

temperature (oC)

0 100 200 300 400 500 600

S-p

ara

mete

r

0.525

0.530

0.535

0.540

Al as-cast

Al-In10

Al-Sn5

bulk

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Diffusion positron trapping model with grain size increase

( / )3( )

1 ( / )

m g b g

b

L L R LS S S S

R LL R L

bL D

( ) coth( ) 1/L z z z

J. Dryzek, Acta Physica Polonica A, 95 (1999) 539

J. Dryzek, Appl. Phys. A 114 (2014) 465-475

0 0( , ) expn n

B

QR t T R t M

k T

where Q is the activation energy of boundary migration

n=2

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Temperature dependences of S-parameter

temperature (oC)

0 100 200 300 400 500 600

S-p

ara

mete

r

0.525

0.530

0.535

0.540

Al as-cast

Al-In10

Al-Sn5

bulk

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Temperature dependences of S-parameter

temperature (oC)

0 100 200 300 400 500 600

S-p

ara

mete

r

0.525

0.530

0.535

0.540

Al as-cast

Al-In10

Al-Sn5

bulk

DTM [Q=(2.12 ±0.4)] eV)

DTM [Q=(0.65 ± 0.2)] eV)

F.J. Humphreys and M.Hatherly, „Recrystallization and related annealing

phenomena”, Elsevier (2004) QB=0.87 eV

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Temperature dependences of S-parameter

temperature (oC)

0 100 200 300 400 500 600

S-p

ara

mete

r

0,520

0,522

0,524

0,526

0,528

0,530

0,532

0,534

0,536

0,538

0,540

Al-Au0.5

Al-Pb10

bulk

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Temperature dependences of S-parameter

temperature (oC)

0 100 200 300 400 500 600

S-p

ara

mete

r

0,520

0,522

0,524

0,526

0,528

0,530

0,532

0,534

0,536

0,538

0,540

Al-Au0.5

Al-Pb10

bulk

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Activation energy of boundary migration determined from the DTM

Alloy Q

(eV)

Al-In10 2.12±0.4

Al-Sn5 1.12±0.2

Al-Pb10 1.43±0.3

Al-Au0.5 1.73±0.4

Al_cast 0.65±0.2

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CDB spectrum of pure alumnium and gold

photon energy (keV)

496 498 500 502 504 506 508 510 512 514 516 518 520 522 524 526

counts

1e+0

1e+1

1e+2

1e+3

1e+4

1e+5

1e+6

electron momentum (mrad)

-50 -40 -30 -20 -10 0 10 20 30 40 50

Aluminium

Gold

core regioncore region band region

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The ratio curve for Au related to Al spectrum

photon energy (keV)

511 512 513 514 515 516 517 518 519 520

ratio to a

nneale

d A

l

0

1

2

3

4

Au

Al

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The ratio curves for Au and Al as-cast related to Al spectrum

photon energy (keV)

511 512 513 514 515 516 517 518 519 520

ratio to a

nneale

d A

l

0

1

2

3

4

Au

Al

Al as-cast

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The ratio curves for Au and Al-Au0.5 related to Al spectrum

photon energy (keV)

511 512 513 514 515 516 517 518 519 520

ratio to a

nneale

d A

l

0

1

2

3

4

Au

Al-Au0.5Al

Al as-cast

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The ratio curves

photon energy (keV)

511 512 513 514 515 516 517 518 519 520

ratio to a

nneale

d A

l

0

1

2

3

4

Au

Al-Au0.5Al

Al as-cast

(1 )alloy Al cast metalN NN

=0.006

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photon energy (keV)

511 512 513 514 515 516 517 518 519 520

ratio to a

nneale

d A

l

0.0

0.5

1.0

1.5

2.0

electron momentum (mrad)

0 5 10 15 20 25 30 35

Al-In10

Al

In

Al as-cast

(1 )alloy Alas cast metalN NN

=0.38

Volume fraction

of In nanoparticles:

0.27

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photon energy (keV)

511 512 513 514 515 516 517 518 519 520

ratio to a

nneale

d A

l

0.0

0.5

1.0

1.5

2.0

electron momentum (mrad)

0 5 10 15 20 25 30 35

Sn

Al-Sn5

Al

Al as-cast

(1 )alloy Al cast metalN NN

=0.23

Volume fraction

of Sn nanoparticles:

0.12

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photon energy (keV)

511 512 513 514 515 516 517 518 519 520

ratio to a

nneale

d A

l

0.0

0.5

1.0

1.5

2.0

electron momentum (mrad)

0 5 10 15 20 25 30 35

Pb

Al-Pb10Al

Al as-cast

(1 )alloy Al cast metalN NN

=0.23

Volume fraction

of Pb nanoparticles:

0.26

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Subsurface zone for Al-In10 alloy

depth from the worn surface (m)

0 50 100 150 200 250 300 350

positro

n m

ean lifetim

e (

ps)

190

200

210

220

230

240

250

260

200 N

50 N

100 N

Al-In10 Load

200+46 exp(-d/95)

200+38 exp(-d/52)

the worn surface

the SZ or workhardening zone

interior

.

.

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Positron beam studies of the Al-Pb10 alloy after friction test.

incident positron energy (keV)

0 10 20 30

S p

ara

mete

r

0,49

0,50

0,51

0,52

depth (nm)

0 483 1664 3428

Al90Pb10_reference

Al90Pb10_10kg

Al90Pb10_20kg

L+=0.74 nm

L+=0.60 nm

doxides = 4.29 nm

L+oxides= 0.90 nm

L+= 55.49 nm

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Conclusions

The embedded nanopraticles in the aluminium host imporve the tribo-

properties, they reduce the wear rate and friction coefficient.

They prevent the grain motion and increase the migration energy

activation.

In the studied triboalloys positrons are trapped at vacancies, preasumbly

located at the interface of the nanoparticles and the aluminium host.

The subsurface zone induced by dry sliding is expanded in the interior at

the depth of 100-300 m depending on the applied load.

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Thank you for your attention