EFFECT OF PLASTIC DEFORMATION AT 8 K ON THE DAMPING SPECTRUM OF ZIRCONIUM

HAL Id: jpa-00223448

https://hal.archives-ouvertes.fr/jpa-00223448

Submitted on 1 Jan 1983

HAL is a multi-disciplinary open access archive for the deposit and dissemination of sci- entific research documents, whether they are pub- lished or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers.

L’archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d’enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

EFFECT OF PLASTIC DEFORMATION AT 8 K ON THE DAMPING SPECTRUM OF ZIRCONIUM

L. Miyada-Naborikawa, R. de Batist

To cite this version:

L. Miyada-Naborikawa, R. de Batist. EFFECT OF PLASTIC DEFORMATION AT 8 K ON THE

DAMPING SPECTRUM OF ZIRCONIUM. Journal de Physique Colloques, 1983, 44 (C9), pp.C9-

651-C9-656. �10.1051/jphyscol:1983998�. �jpa-00223448�

JOURNAL DE PHYSIQUE

Colloque C9, suppl6ment a u n012, Tome 44, d k e m b r e 1983 page C9-651

EFFECT OF PLASTIC DEFORMATION AT 8 K ON THE DAMPING SPECTRUM OF ZIRCONIUM

L.T. Miyada-Naborikawar and R. de ~ a t i s t ~ ~

Materiazs Science Department, S. C. K/C. E . N., B-2400 Mol, BeZgium

Rgsume

-

Le f r o t t e m e n t i n t e r i e u r du Z r e n t r e 80 e t 300 K, mesure apres de- f o r m a t i o n .3 8 K ou 2 300 K e t v i e i l l i s s e m e n t 1 temperature ambiente e s t i n t e r - p r e t e comme r e s u l t a n t de r e l a x a t i o n s du ty?e Bordoni, d ' e f f e t Snoek (H) dans l e s champs de f o r c e des d i s l o c a t i o n s e t de mouvements de j o i n t s de mbcles.

A b s t r a c t

-

The i n t e r n a l f r i c t i o n o f Zr, between 80 K and 300 K, measured f o t l o w i n g p l a s t i c deformation a t 8 K o r a t 300 K and room temperature ageing

i s i n t e r p r e t e d i n terms o f k i n k p a i r generation, d i s l o c a t i o n enhanced hydro- gen Snoek r e l a x a t i o n and t w i n boundary m i g r a t i o n .

INTRODUCTION

The low temperature i n t e r n a l f r i c t i o n spectrum o f p l a s t i c a l l y deformed zirconium i s c h a r a c t e r i z e d by a broad maximum o c c u r r i n g a t about 205 K f o r a frequency of 1 kHz (1). A systematic i n v e s t i g a t i o n o f the e f f e c t o f deformation and annealing (2,3) i n - d i c a t e s t h a t t h i s peak appears t o e x h i b i t a number o f t h e c h a r a c t e r i s t i c s correspon- d i n g w i t h k i n k p a i r g e n e r a t i o n processes. Yet, o t h e r experiments (4,5,6) seem t o suggest t h a t t h i s r e l a x a t i o n peak m i g h t be r e l a t e d t o d i s l o c a t i o n - p o i n t d e f e c t i n - t e r a c t i o n e f f e c t s . This i n t e r p r e t a t i o n found some support i n the observation o f a r e l a x a t i o n peak a t about 90 K, f o l l o w i n g deformation a t lower temperatures, which was t h e r e f o r e a t t r i b u t e d t o i n t r i n s i c d i s l o c a t i o n r e l a x a t i o n . However, t h i s 90 K peak i s r a t h e r unstable a g a i n s t room temperature ageing and i n view a l s o o f i t s narrowness, a mechanism based on p o i n t d e f e c t r e o r i e n t a t i o n has been proposed i n (7).

F u r t h e r support f o r a d i s l o c a t i o n p o i n t d e f e c t i n t e r a c t i o n model i s claimed (4,6) from the i n f l u e n c e on the 205 K peak behaviour o f thermal annealing f o l l o w i n g low temperature deformation ( 4 ) and o f doping w i t h hydrogen ( 5 ) . O f course, t h e s t r o n g a f f i n i t y o f zirconium f o r gaseous i m p u r i t i e s makes a study o f i n t r i n s i c r e l a x a t i o n processes i n t h i s m a t e r i a l r a t h e r d i f f i c u l t , and t h i s has c e r t a i n l y c o n t r i b u t e d t o the d i v e r s i t y i n i n t e r p r e t a t i o n o f t h e low temperature r e l a x a t i o n peaks i n zirconium.

I n t h e p r e s e n t work, t h e e f f e c t o f t e n s i l e deformation a t e i t h e r room temperature o r l i q u i d h e l i u m temperature has been s t u d i e d i n z i r c o n i u m specimens p r e v i o u s l y out- gassed i n u l t r a h i g h vacuum. These experiments have revealed t h e very complex nature of t h e damping spectrum between 80 and 300 K, and they have shown t h a t the r e l a x a - t i o n s t r e n g t h o f some o f t h e components o f the r e l a x a t i o n spectrum can be s t r o n g l y increased i n a number o f p a r t i c u l a r experimental circumstances. Transmission e l e c - t r o n microscopy has been used t o t r y and o b t a i n i n f o r m a t i o n about t h e p a r t i c u l a r m i c r o s t r u c t u r e s corresponding w i t h p a r t i c u l a r damping spectra.

EXPERIMENTAL

Specimens of 99.99 % zirconium were o b t a i n e d from Fqaterials Research Corporation.

They were annealed f o r 30 min. a t 1580 K f o l l o w e d by 30 min. a t 1050 K ( t o minimize

*On leave from IPEN, SAO PAUL0 (Brasi 1 )

.

**

A1 so a t R.U.C. Antwerpen, B-2020 ANTWERPEN (Belgium).

Article published online by EDP Sciences and available at http://dx.doi.org/10.1051/jphyscol:1983998

C9-652 JOURNAL DE PHYSIQUE

the d i s l o c a t i o n d e n s i t y r e s u l t i n g from c o o l i n g , through the bcc t o hcp phase t r a n s - formation) and f a s t c o o l i n g . The pressure d u r i n g annealing was maintained below 3 x 10-7 Pa. Samples had a thickness o f .3 mm and were c u t i n a dumbbell shape (gauge l e n g t h o f 11 m) t o a l l o w t e n s i l e deformation i n an I n s t r o n machine and dam- p i n g measurement i n f l e x u r a l resonance, t h e specimen being c a n t i l e v e r - 1 i ke clamped w i t h no e f f e c t on t h e l o c a l l y deformed p o r t i o n o f the specimen. Resonance frequency f o r the specimen geometry used was about 80 Hz.

E l e c t r o n microscopic observations were performed by means o f a 200 kV JEOL.

The i n t e r n a l f r i c t i o n spectra have been analysed as a s u p e r p o s i t i o n o f Debye r e l a x a - t i o n peaks, using a n o n - l i n e a r l e a s t squares computer programme t o o b t a i n f i t t e d values f o r t h e r e l a x a t i o n parameters ( r e l a x a t i o n strength, peak temperature, e f f e c - t i v e a c t i v a t i o n e n t h a l p y ) , u s i n g i n i t i a l values f o r peak temperature and a c t i v a t i o n enthalpy taken from Arrhenius p l o t s d e r i v e d from a v a i l a b l e l i t e r a t u r e data ( 8 ) .

EXPERIMENTAL RESULTS

The i n t e r n a l f r i c t i o n of a specimen deformed a t 300 K t o about 18 % i s shown i n F i g . 1, t o g e t h e r w i t h t h e decomposition i n f o u r Debye r e l a x a t i o n s , peaking a t 148 K ( P i ) , 170 K (Pd)

,

212 K (PI) and 230 K ( P 2 ) , r e s p e c t i v e l y .

F i g . 1

-

I n t e r n a l f r i c t i o n and modulus o f zirconium deformed 18 % a t 300 K, w i t h the decomposition i n

Debye r e l a x a t i o n s .

F o l l o w i n g t e n s i l e deformation near 8 K, a new I . F . peak i s observed a t 280 K, as shown i n F i g . 2a,b f o r 11 % and 12 % s t r a i n , r e s p e c t i v e l y . These f i g u r e s i n d i c a t e t h a t the r e l a x a t i o n s t r e n g t h o f t h e 280 K peak i s n o t determined o n l y by the amount of deformation. TEM observation o f these specimens revealed t h a t t h e specimen i n which the s t r e n g t h of t h e 280 K peak was l a r g e s t contained a much l a r g e r concentra- t i o n o f deformation twins (Figs. 3 and 4).

The v a r i a t i o n o f the peak h e i g h t s w i t h t h e degree o f deformation a t 8 K i s shown i n F i g . 5. Peaks PA and P behave r a t h e r analogously, going through a maximum f o r a defermation o f about 19 %. The peak h e i g h t o f P2 does n o t appear t o change very much, i n c o n t r a s t w i t h PI, which becomes very l a r g e f o r a r a t h e r narrow s t r a i n i n t e r v a l around 6 %. Since t h e peak a t 280 K has been r e l a t e d w i t h the t w i n d e n s i t y r a t h e r than w i t h t h e amount o f p l a s t i c s t r a i n , i t was n o t i n c l u d e d i n t h i s f i g u r e . The peak h e i g h t of P1 was found sometimes t o vary w i t h ageing a t room temperature;

t h i s i s shown i n F i g . 6 f o r a specimen deformed 3 % a t room temperature.

Fig. 2a,b

-

Damping spectrum and modulus o f Z r deformed 11 % a t 8 K (a) o r 12 % a t 8 K ( b ) .

F i g . 3

-

M i c r o s t r u c t u r e corresponding F i g . 4

-

M i c r o s t r u c t u r e corresponding t o t h e specimen deformed 11 % a t 8 K. t o t h e specimen deformed 12 % a t 8 K.

DISCUSSION

The generation o f the 280 K peak by low temperature deformation agrees w i t h t h e ob- s e r v a t i o n o f Reed H i l l e t a1

.

( 9 ) t h a t t h e room temperature damping o f z i r c o n i u m was increased by t h e t w i n s produced d u r i n g / 7 K deformation. TEM has confirmed t h a t the t w i n s formed a t 8 K are a l s o of the i1121) <1126> type. I t thus appears t h a t t h e 280 K damping peak i s caused by t w i n boundary m i g r a t i o n processes.

The peak PI i s observed b o t h i n t h e w e l l annealed s t a t e and a f t e r a heavy t e n s i l e deformation. The f a c t t h a t i t s peak h e i g h t becomes v e r y l a r g e f o r an i n t e r m e d i a t e amount o f deformation and t h a t under those c o n d i t i o n s i t i s s t r o n g l y dependent on room temperature ageing suggests t h a t i t i s r e l a t e d w i t h both the d i s l o c a t i o n densi- t y and t h e c o n c e n t r a t i o n o f some k i n d o f p o i n t d e f e c t s . Furthermore, t h e e f f e c t of ageing i n d i c a t e s t h a t t h e d i f f u s i o n o f those p o i n t d e f e c t s towards t h e d i s l o c a t i o n s i s an e s s e n t i a l s t e p i n t h e development o f a l a r g e r e l a x a t i o n s t r e n g t h f o r PI. I n - t r i n s i c p o i n t d e f e c t s can probably be r u l e d o u t as c o n t r i b u t i n g t o PI, since s e l f - i n t e r s t i t i a l s are expected t o have annealed d u r i n g stage I, which i s terminated a t about 160 K ( l o ) , so t h a t no e x t e n s i v e f u r t h e r m o b i l i t y i s expected t o occur so as t o g i v e r i s e t o changes a t room temperature spread o u t over several days. Likewise vacancies appear t o be u n l i k e l y candidates s i n c e t h e i r d i f f u s i o n occurs presumably above room temperature and a1 so s i n c e f o l lowing deformation and s e l f - i n t e r s t i t i a l a n n i h i l a t i o n , t h e i r c o n c e n t r a t i o n i s probably n o t l a r g e enough. T h i s leaves us w i t h

JOURNAL DE PHYSIQUE

Fig. 5

-

Variation of t h e peak heights with t h e degree of de- formation a t 8 K.

impurity atoms t o e x p l a i n PI. The width of PI i n d i c a t e s t h a t i f i t i s t o be a r e l a x a t i o n peak, i t s a c t i v a t i o n enthalpy cannot be s m a l l e r than about 0.5 eV. This value i s c o n s i s t e n t with t h e migration enthalpy of hydrogen i n a . Z r (0.59 eV) ( 1 1 ) . Hence P 1 could be r e l a t e d t o s t r e s s induced r e o r i e n t a t i o n of hydrogen atoms, which agrees with t h e r e l a t i v e l y l a r g e value of t h e pre-exponential frequency f a c t o r f o

(about 6 x 1013 s - 1 ) . Although i n t e r s t i t i a l i m p u r i t i e s occupying,as does hydrogen ( 1 2 , 1 3 ) , t e t r a h e d r a l p o s i t i o n s i n t h e hcp l a t t i c e a r e not expected t o lead t o a s t r e s s induced r e o r i e n t a t i o n by executing jumps between t e t r a h e d r a l s i t e s , i t has been shown (14) t h a t a r e l a x a t i o n e f f e c t can be expected i f the i n t e r s t i t i a l impuri- t y can be induced t o make t e t r a h e d r a l - o c t a h e d r a l jumps. Taking f u r t h e r account of our TEM observation t h a t even a f t e r high vacuum outgassing very few hydride p r e c i - p i t a t e s can s t i l l be p r e s e n t i n zirconium, i t can be assumed t h a t s u f f i c i e n t y e t not t o o much hydrogen i s a v a i l a b l e i n s o l i d s o l u t i o n i n our specimens.

Since ageing a t room temperature can, under favourable c o n d i t i o n s , s t r o n g l y i n c r e a s e t h e r e l a x a t i o n s t r e n g t h , presumably by allowing t h e hydrogens t o g a t h e r a t t h e d i s - l o c a t i o n s , i t i s suggested t h a t P1 i s caused by a d i s l o c a t i o n enhanced Snoek type

Fig. 6

-

Variation of t h e peak height f o r P 1 with ageing a t room temperature, f o r a specimen deformed 3 % a t 300 K.

r e l a x a t i o n process ( 1 5 ) . The f a c t t h a t a l a r g e and r a t h e r s t a b l e ( a g a i n s t prolonged room temperature ageing) PI can be observed o n l y i n p r e v i o u s l y outgassed specimens (though s t i 11 c o n t a i n i n g hydrogen) deformed t o a f a i r l y s t r i c t l y del i n e a t e d amount o f s t r a i n suggests t h e n e c e s s i t y o f a r a t h e r s u b t l e balance between hydrogen concen- t r a t i o n and d i s l o c a t i o n d e n s i t y . This may h e l p e x p l a i n why PI peaks described so f a r i n t h e l i t e r a t u r e have been r a t h e r small and n o t very s t a b l e and r e p r o d u c i b l e . The a n a l y t i c a l f i t t i n g o f t h e experimental damping curves c l e a r l y i n d i c a t e s the pre- sence o f a peak PA ( a t 148 K), i n a d d i t i o n t o the l a r g e Pd peak ( a t 170 K). The two peaks f o l l o w t h e same p a t t e r n as a f u n c t i o n o f deformation ( e i t h e r a t 300 K o r a t 8 K), and t h e r e are i n d i c a t i o n s t h a t t h e y a l s o behave s i m i l a r l y w i t h respect t o annealing ( 2 ) . Taken together w i t h t h e r e l a t i v e l y low value o f fo (about 5 x 1 0 l 0 s - I ) , these observations suggest t h a t b o t h Pd and PA m i g h t be caused by k i n k p a i r generation processes. I t i s well-known t h a t t h e s l i p systems i n zirconium, as a l s o i n t i t a n i u m , are n o t r e s t r i c t e d t o t h e basal plane, b u t t h a t p l a s t i c deformation occurs p r e f e r e n t i a l l y by p r i s m a t i c s l i p and t o some e x t e n t a l s o by pyramidal s l i p , w i t h o n l y a l i m i t e d c o n t r i b u t i o n o f basal s l i p (16,17,18).

I n t h e annealed specimens, t h e m a j o r i t y o f t h e d i s l o c a t i o n s ( f r e q u e n t l y arranged i n subgrain boundaries on t h e basal planes) were found t o have Burgers vectors o f t h e type a/3 <1120>. These o f course can c o n t r i b u t e t o s l i p on t h e p r i s m a t i c and t h e pyramidal s l i p systems, and i t i s n o t unreasonable t h e r e f o r e t o assume t h a t Pd and P i correspond w i t h the k i n k p a i r generation r e l a x a t i o n processes f o r these two s l i p sys terns.

The peak P2 has been observed i n the present study i n b o t h annealed and deformed specimens, t h e r e l a x a t i o n s t r e n g t h being r e l a t i v e l y independent o f t h e amount o f deformation. I t i s n o t obvious from t h e peak p o s i t i o n s a t d i f f e r e n t frequencies w i t h what peaks observed i n o t h e r i n v e s t i g a t i o n s i t can be c o r r e l a t e d . This d i f f i c u l t y i s s t i 11 more pronounced i f one considers t h e unstabi 1 i t y a g a i n s t room temperature annealing o f most o f the peaks described i n t h e l i t e r a t u r e , i n c o n t r a s t w i t h t h e r a t h e r s t a b l e behaviour o f t h i s peak i n t h e present work. I n view o f the s c a r c i t y o f convincing data, i t appears premature t o t r y and attempt an i n t e r p r e t a t i o n f o r t h i s peak.

CONCLUSIONS

The r e s u l t s o f t h i s study can be b r i e f l y summarized as f o l l o w s :

-

A peak a t 280 K (80 Hz) appears t o be r e l a t e d w i t h t w i n boundary motion.

-

The P1 peak (210 K, 80 Hz) i s suggested t o be caused by a d i s l o c a t i o n enhanced hydrogen Snoek t y p e r e 1 a x a t i o n e f f e c t .

-

Both Pd and P' (148, 170, 80 Hz) are i n t e r p r e t e d as k i n k p a i r generation peaks i n a a/3 <1120> i i s l o c a t i o n s g l i d i n g i n t h e p r i s m a t i c o r pyramidal s l i p systems.

ACKNOWLEDGEMENTS

Discussions w i t h Dr. P. D e l a v i g n e t t e about t h e TEM observations are g r a t e f u l l y acknowledged.

REFERENCES

(1) HASIGUTI, R.R., IGATA, N. and KAMOSHITA, G., Acta ?let. 10 (1962) 442.

( 2 ) PETIT, J., QUINTARD, M., SOULET, R. and DE FOUQUET, J . , J . de Phys. - 32 (1971) C2-215.

(3) SAVINO, E.J. and BISOGNI, E.A., J. de Phys. 32 (1971) C2-209.

(4) SAVINO, E.J. and BISOGNI, E.A., J. Nucl. M a t 7 5 0 (1974) 298.

(5) POVOLO, F. and BISOGNI, E.A., J. Nucl. Mat. 2971969) 82.

( 6 ) PETIT, J., QUINTARD, M., MAZOT, P. and DE FOWUET, J., Proc. 5 t h ICIFUAS, Aachen, Vol. 2 (1975) 402.

C9-656 JOURNAL DE PHYSIQUE

( 7 ) PETIT, J., QUINTARD, M. and FERRON, G., J. Nucl. Mat. 56 (1975) 341.

( 8 ) MIYADA-NABORIKAWA, L.T., DE BATIST, R. and EERSELS, L.J,. Phys. - 42 (1981) C5-283.

( 9 ) REED-HILL, R.E., DAHLBERG, E.P. and SLIPPY, W.A.Jr., Trans. Met. Soc. AIME

-

233 ( 1965) 1766.

(10) NEELY, H.H., R a d i a t . E f f . 3 (1970) 189.

( 1 1 ) F1AZZOLA1, F.M. and RYLL-NARDZEWSKI, J., 4. Less Common Met. 49 (1976) 323.

(12) NARANG, P.P., PAUL, G.L. and TAYLOR, K.N.R., J . Less Common %t. 56 (1977) 125.

( 1 3 ) DARBY, M.J., READ, M.N. and TAYLOR, K.N.R., p h y s . s t a t . s o 1 . ( a ) 5 0 7 1 9 7 8 ) 203.

( 1 4 ) POVOLO, F. and BISOGNI, E.A., A c t a Met. 15 (1967) 701.

( 1 5 ) SCHOECK, G., Phys. Rev. 102 (1956) 1458.-

(16) TIWARI, S.N., LLOYD, J .

and

TANGRI, K., M e t a l l . Trans.

3

(1972) 2605.

( 1 7 ) LEVINE, E.D., Trans. JIM

2

(1968) 832.

(18) RAPPERPORT, E.J. A c t a M e t .

L

(1959) 254.