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THE CHARACTERIZATION OF
PRETRANSFORMATION MORPHOLOGIES : PERIODIC STRAIN MODULATIONS
L. Tanner, A. Pelton, R. Gronsky
To cite this version:
L. Tanner, A. Pelton, R. Gronsky. THE CHARACTERIZATION OF PRETRANSFORMATION
MORPHOLOGIES : PERIODIC STRAIN MODULATIONS. Journal de Physique Colloques, 1982,
43 (C4), pp.C4-169-C4-172. �10.1051/jphyscol:1982419�. �jpa-00222133�
JOURNAL DE PHYSIQUE
Colloque C4, suppldment au n o 12, Tome 43, dBcembre 1982 page C4-169
THE CHARACTERIZATION OF PRETRANSFORMATION MORPHOLOGIES
:
PERIODICS T R A I N MODULATIONS
L . E . Tanner, A. R. ~ e l t o n * a n d R. Gronsky**
M a t e r i a l s Science D i v i s i o n , Lawrence L i v e m o r e National Laboratory, Livermore, C a l i f o r n i a 94550, U.S.A.
*Department o f Materials Science, S t a n f o r d I l n i v e r s i t y , S t a n f o r d , C a l i f o r n i a 94305, U.S.A.
**NationaZ Laboratory for Electron Microscopy, Materials and Molecular Research Division, Lawrence Berkeley Luboratory, Berkeley, C a l i f o r n i a 94720, U . S . A .
(Accepted 4 October 1 9 8 2 )
A b s t r a c t .
-
The p a r e n t c u b i c phases o f a l l o y s which undergo m a r t e n s i t i c t r a n s f o r m - a t i o n s e x h i b i t v a r i o u s p r e t r a n s f o r m a t i o n a l e f f e c t s i n c l u d i n g t h e development o f f i n e - s c a l e p e r i o d i c s t r a i n modulations. T h i s d i f f u s e m i c r o s t r u c t u r e , r e v e a l e d by e l e c t r o n microscopy and d i f f r a c t i o n , i s i d e n t i f i e d as a dense a r r a y o f incommensu- r a t e shear s t r a i n s o f {110} <110> type. T h i s behavior, which r e s u l t s i n ani n c i p i e n t l o s s o f c u b i c symmetry, appears t o be r e l a t e d t o t h e c o n c u r r e n t p a r e n t l a t t i c e s o f t e n i n g ( i . e . t h e decrease o f C' w i t h d e c r e a s i n g temperature approaching MS) t h a t i s observed i n most o f t h e same a1 loys.
S o l i d s t a t e phase t r a n s f o r m a t i o n s proceed by a v a r i e t y o f mechanisms i n v o l v i n g e i t h e r t h e r m a l l y a c t i v a t e d d i f f u s i o n a l atomic rearrangements o r athermal d i f f u - s i o n l e s s atomic displacements. M u l t i p l e t r a n s i t i o n s a r e a l s o p o s s i b l e , o c c u r r i n g s e q u e n t i a l l y o r c o n c u r r e n t l y depending upon t h e i n t e r p l a y o f thermodynamic and k i n e t i c f a c t o r s e s t a b l i s h e d b y m a t e r i a l t r e a t m e n t c o n d i t i o n s . I n t h e course o f such t r e a t m e n t cycles, p a r e n t phases o f t e n develop f l u c t u a t i o n s i n atomic o r d e r o r c o n c e n t r a t i o n and/or l a t t i c e s t r a i n and t h e s e t e n d t o a n t i c i p a t e c r i t i c a l charac- t e r i s t i c s of t h e impending t r a n s i t i o n ( s ) . Of these, f l u c t u a t i o n s i n s t r a i n a r e u s u a l l y a s s o c i a t e d w i t h t h e d i s p l a c i v e mechanisms and i n p a r t i c u l a r , a p e r i o d i c m o d u l a t i o n o f shear s t r a i n s has been found t o be common t o most o f t h e v a r i o u s and d i v e r s e a l l o y systems t h a t undergo m a r t e n s i t i c t r a n s f o r m a t i o n s [1,2]. A represen- t a t i v e , though f a r f r o m an a l l i n c l u s i v e l i s t i n g o f t h e systems i n which these e f f e c t s have been observed i s g i v e n i n t a b l e 1.
The s t r a i n m o d u l a t i o n s a r e r e a d i l y d e t e c t e d by e l e c t r o n microscopy and e l e c - t r o n and x - r a y d i f f r a c t i o n . Transmission e l e c t r o n micrographs e x h i b i t a f i n e -scale, d i f f u s e , s t r i a t e d m i c r o s t r u c t u r e which i s commonly r e f e r r e d t o as "tweed"
and i s shown i n f i g u r e s la,b and 3 [3]. The s t r i a t i o n s , t y p i c a l l y o f 3-6 nm p e r i o d i c i t y , l i e p a r a l l e l t o {110} t r a c e s o f t h e p a r e n t c u b i c phases, where
t h e p a r e n t s t r u c t u r e may be v a r i o u s l y d i s o r d e r e d bcc, d i s o r d e r e d f c c o r ordered 82, D O j , L12, e t c . ( s e e t a b l e 1). The corresponding d i f f r a c t i o n p a t t e r n s r e v e a l d i f f u s e r e l - s t r e a k s a l o n g <110>* a t each Bragg r e f l e c t i o n as seen i n f i g u r e l c as w e l l as s c h e m a t i c a l l y i n f i g u r e 2 [ 3 ( a ) , ( b ) ] . The unique f e a t u r e s o f t h e d i f f u s e s c a t t e r i n g a r e as f o l l o w s : s t r e a k i n g i s n o t p r e s e n t a t 000, whereas s e l e c t e d s t r e a k absences o c c u r s y s t e m a t i c a l l y a t each r e f l e c t i o n , and t h e l e n g t h o f s t r e a k s i n c r e a s e s w i t h i n c r e a s i n g o r d e r o f r e f l e c t i o n . The d i f f u s e i n t e n s i t y , Id, about each Bragg r e f l e c t i o n i s r e l a t e d t o s t r a i n b y
Id 2. E k '
g
Article published online by EDP Sciences and available at http://dx.doi.org/10.1051/jphyscol:1982419
C 4 - 1 7 0 JOURNAL DE PHYSIQUE
F i g . 1 : Cu-6.6 a t . % Be (1.0 wt.%) as-quenched t o room temperature. S i n g l e phase f c c e x h i b i t i n g (110) <110> p e r i o d i c s t r a i n m o d u l a t i o n s . { I 1 0 1 tweed i n 2-beam BF ima es, [001] o r i e n - t a t i o n , ( a ) g=[OOZ]*, ( b ) g=fZZO]*, ( c ) L001]*
SADP showing <I 1 O y r e l - s t r e a k s .
F i g . 2 : Schematic r e p r e s e n t a t i o n of t h e < l l O > * s t r a i n d i f f u s e s c a t t e r i n g i n
F i g . 3 Tweed s t r a i n c o n t r a s t due t o (1101 <11C> p e r i o d i c s t r a i n modula t i o n s w i t h i n p a r e n t c u b i c phases o f ( a ) Mn-26 a t . % Cu a t %180°K
(from K. S h i m i z u ) , ( b ) Fe
-
30.6 a t . % Pd a t 213OK ( f r o m R. Oshima) and ( c ) N i-
36.8 a t . % A1 a t room t e m p e r a t u r e (from A. Lasalmonie).where l a t t i c e s t r a i n s a r e r e p r e s e n t e d by a d i s p l a c e m e n t wave o f v e c t o r Sk and
g
i s a r e c i p r o c a l l a t t i c e v e c t o r [4,5]. S t r e a k s a r e t h e r e f o r e absent when- -
c k g = 0. Note t h a t t h e same c r i t e r i o n a l s o a p p l i e s t o t h e m i c r o s t r u c -
t u r e ; t h a t i s , tweed s t r i a t i o n s absent i n an image a r e t h o s e which would l i e along t r a c e s normal t o t h e d i r e c t i o n s o f m i s s i n g r e l - s t r e a k s i n a c o r r e s p o n d i n g d i f f r a c - t i o n p a t t e r n [ 3 ( a ) ] . The f o r e g o i n g u n i q u e l y i d e n t i f i e s t h e s t r a i n s as shears o f {110} <110> t y p e o r e q u i v a l e n t l y model l e d as t r a n s v e r s e displacement waves o f
<110>wave v e c t o r and <110> p o l a r i z a t i o n v e c t o r .
The i n t e r a c t i o n o f such waves can be shown t o g i v e r i s e t o a modulated a r r a y o f incommensurate d i s p l a c e m e n t s ( s t a t i c and/or dynamic). The r e s u l t i s an i n c i - p i e n t l o s s o f c u b i c symmetry which t r a n s l a t e s t h e p a r e n t phase toward t e t r a g o n a l symmetry as t h e t r a n s f o r m a t i o n i s approached [5]. T h i s b e h a v i o r can be r e l a t e d t o t h e c o n c u r r e n t t e m p e r a t u r e dependent " s o f t e n i n g " o f t h e p a r e n t l a t t i c e s i n c e t h e a p p r o p r i a t e shears a r e i n v o l v e d . That i s , t h e s e c u b i c phases g e n e r a l l y e x p e r i e n c e an anomolous decrease of t h e e l a s t i c c o n s t a n t s C' = 1/2(Cll-C12) w i t h decreas- i n g t e m p e r a t u r e approaching Ms l s e e t a b l e 1 ) [6]. I n a d d i t i o n , t h e r e i s mounting e v i d e n c e t h a t {110} <110> shears a r e c h a r a c t e r i s t i c o f t h e i n i t i a l
s t e p i n t h e f o r m a t i o n m a r t e n s i t e i n most systems [1,2,6,10]. These apparent l i n k s i n s t r u c t u r e and b e h a v i o r seem more t h a n c o i n c i d e n t a l and t h u s suggest an i n t i m a t e r e l a t i o n s h i p between t h e p r e t r a n s f o r m a t i o n a l v a r i a t i o n s i n s t a t e and t h e marten- s i t i c t r a n s f o r m a t i o n s themselves. P r o p e r e l u c i d a t i o n o f t h e n a t u r e and s i g n i f i - cance o f t h e f o r e g o i n g w i l l r e q u i r e f u r t h e r e x p e r i m e n t a l i n v e s t i g a t i o n , as w e l l as t h e o r e t i c a l m o d e l l i n g . Our approach t o t h e f o r m e r i s t o c a r r y o u t s t r u c t u r a l s t u d i e s u t i l i z i n g h i g h r e s o l u t i o n e l e c t r o n microscopy. As t o t h e l a t t e r , s e v e r a l new t h e o r i e s i n c o r p o r a t i n g p r e t r a n s f o r m a t i o n a l e f f e c t s , l o c a l i z e d s o f t phonon mode concepts and/or n o n - c l a s s i c a l n u c l e a t i o n a r e c u r r e n t l y b e i n g developed [7-101.
Acknowledgements.
-
T h i s work was supported i n p a r t b y t h e O f f i c e o f B a s i c Energy Sciences, D i v i s i o n o f M a t e r i a l s Science o f t h e U.S. Department o f Energy underC o n t r a c t DE-AC03-76SF00098 and t h e N a t i o n a l Science F o u n d a t i o n under C o n t r a c t DMR-7803894. One o f us (L.E.T.) wishes t o thank P r o f . G. Thomas f o r an a p p o i n t - ment t o t h e LBL s t a f f d u r i n g 1980-81.
References
[I] Shape Memory E f f e c t s i n A l l o y s , J. Perkins, ed. (Plenum Press, N.Y.) 1975.
[ 2 ] Proc. ICOMAT-79 (MIT, Cambridge) 1979.
[ 3 ] ( a ) TANNER, L. E., P h i l . Mag., 14 (1966) 111. ( b ) KAINUMA, T. and HATANABE, R., J. Jap. I n s t . Met., 35 ( 1 9 m 1126. ( c ) PHILLIPS, V. A. and TANNER, L. E., A c t a Met., 21 (1973) 4 4 1 7 ( d ) TANNER L. E. and LAUGHLIN, 0. E., Proc. EMSA ( C l a i t o r ' s F e s s , Baton Rouge) 1975, p. 20.
[ 4 ] GUINIER, A., X-Ray D i f f r a c t i o n o f C r y s t a l s (Freeman, San F r a n c i s c o ) 1963, p. 196.
[ 5 ] MCCONNELL, J. 0. C., Miner. Mag., 38 (1971) 1.
[ 6 ] ( a ) NAKANISHI, N., Ref. [I] p. 1 4 7 7 ( b ) NAKANISHI, N., e t a1 t h e s e proceedings.
[ 7 ] ( a ) CLAPP, P., Phys. S t a t . Sol.
57b
(1973) 561. ( b ) Met. Trans.,j g
(1981) 589.[8] GUENIN, G. and GOBIN, P. F., Met. Trans.,
13A
(1982) 1127.[9J OLSON, G. B. and COHEN, M., t h e s e proceedings.
C
lOJ MENDELSON, S., t h e s e proceedings.JOURNAL DE PHYSIQUE
t a b l e 1 A1 l o y S j s t e m
. -
Mn-Ga Fe-Ni Fe-Pd Fe-Pt
v - 0 Cu-Zn Ni-A1
P a r e n t Pnase C' S o f t e n i n g
S t r u c t u r e Observed R e f e r e n c e -
f c c J LASALMONIE, A., e t a l , Proc. ICOMAT-79 (::IT, Camb.) 1979, P. 538.
NITTONO. 0.. e t d l . Trans. Jao. I n s t . Me:.. 23 ( 1 9 8 2 ) 285.
f c c n o d a t a
f cc f
f CC /
L 12 f
fcc,bcc.82 n o d a t a
bc c no d a t a
8 2 J
82 J
. -
SHIMIZU; L . ; e t a l ; Trans. ~ a I n s t . b Met., 23 ( 1 9 8 2 j 53.
VINTAIKIN. E. 2 . . e t a l , Sov. ~ h y s . Dokl., z(1981) 617.
VLASOVA, E . N., e t a l , Sov. Phys. Dokl., 22 (1977) 765.
KONDRAT'YEV, V. V., e t d l , PM!, 45, No. 4 (1978) 82.
OSHIIW, R., S c r i p t a Met.. 15 (1981) 829.
SATO, M., e t a l . J. Phys. F-(1982) i n prtrss.
FOOS, M., e t a l , P r o c . ICOMAT-79 (MIT, Carib.) 1979, p . 485.
FOOS, M., e t a l , A c t a Met.. 29 ( 1 9 8 1 ) 1091.
AUVRAY, X . . e t a l , S c r i p t a Met., L ( l 9 7 4 : 995.
SVANIOZE, C. S., e t a l , FMM, 51, No. 5 (1981) 883.
GIRAUD-HERAUO, F., Mem. Sci. Rev. Met 71 (1974) 37.
BLAKE, D., PhyS. Met. of U A l l o y s , ( ~ : k ~ ~ i l l , 80s.) 1976, p.189.
HIRAGA, K., e t a l , Jap. J. Appl. Phys., 19 ( 1 9 8 0 ) 397.
OTSUKA, K., e t a l , Met. Trans., 1LA (19:jiT 595.
ENAMI, K., e t a l , S c r i p t a Met., 10 (1976) 879.
LASALMONIE, A., S c r i p t a Met., ( 1 9 7 7 ) 527.
MUKHERJEE. K., Shape Mem. E f f e c t s i n A l l o y s ( P l e n u m , NY) 1975 11.177.
