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SHAPE MEMORY EFFECT IN Cu-Al-Be TERNARY ALLOYS
A. Higuchi, K. Suzuki, Y. Matsumoto, K. Sugimoto, S. Komatsu, Y.
Nakamura
To cite this version:
A. Higuchi, K. Suzuki, Y. Matsumoto, K. Sugimoto, S. Komatsu, et al.. SHAPE MEMORY EFFECT IN Cu-Al-Be TERNARY ALLOYS. Journal de Physique Colloques, 1982, 43 (C4), pp.C4-767-C4-772.
�10.1051/jphyscol:19824125�. �jpa-00222108�
JOURNAI, DE PHYS l Q U E
CoZioqi..e C4, suppZ5rnent a z ~ n o 12, 'l'ome 43, cl5cernbi.e 7982
SHAPE MEMORY EFFECT IN Cu-Al-Be TERNARY ALLOYS
A. lliguchi
,
K. Suzuki,
Y. Matsumoto,
K . ~ugimoto*,
S. ~ o m a t s u * and Y . ~akamura*.%m?:torno Specia Z I4etnls Cc. Trtd., Osaka, Japan
*Depa-~rnent o r MeLaZZ7~rg!~, Kansai University, Suita, Osaka, Japan ( K c v i s e d t e x t accepted 2 8 September 1 9 8 2 )
Abstract.-Changes i n e l e c t r i c a l r e s i s t i v i t y , i n t e r n a l f r i c t i o n and Young's modulus with temperature have been examined on a s e r i e s of beta-phase specimens i n t h e hypoeutectoid r e g i o n of t h e Cu-Al-Be t e r n a r y system.
Existence of transformations from beta-phase t o m a r t e n s i t e phase on cooling a d from m a r t e n s i t e phase t o beta-phase on h e a t i n g was confirmed by t h e temperature changes i n t h e p r o p e r t i e s . An e m p i r i c a l formula was derived on t h e r e l a t i o n between Ms-temperature and t h e content of t h e c o n s t i t u t i o n a l elements. Both one May and two way memory e f f e c t s were r e a l i z e d i n t h e specimens.
1. 111troduction.-NiTi a l l o y i s v e l l kno~m and h a s been used p r a c t i c a l l y a s a shape memory a l l o y s i n c e e a r l y t i n e s ( I ) , b u t t h i s a l l o y i s v e r y expensive because of l e s s p r o d u c i b i l i t y . On t h e o t h e r hand, many i n v e s t i g a t i o n have been r e p o r t e d on Cu-base shape memory a l l o y s c o n s i s t i n g of economical m a t e r i a l s , such a s
Cii-Zil-Al (21, Cu-Al-Ni ( 3 ) , Cu-Zn-Si
( 4 )
and Gu-Zn-Ga (5). Among them, Cu-Zn-Al a l l o y has become v e r y popular a s a Cu-base shape memory a l l o y .With r e g a r d t o Cu-Al-Be t e r n a r y a l l o y , Nickel r e p o r t e d t h a t t h e beta-phase r e g i o n of Cu-A1 b i n a r y a l l o y system was extended t o lower aluminium side by a d d i t i o n of b e r y l l i u u (6) and Prawdzik scggested t h a t t h e Ms-temperature appeared t o be extremely lowered by a d d i t i o n of beryllium (7). The r e l a t i o n between Ms-temperature and beryllium content h a s n o t been r e p o r t e d yet. i'here h a s not been a l s o r e p o r t e d on t h e 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 behavior and t h e shape memory e f f e c t i n Cu-Al-Be t e r n a r y a l l o y system. Therefore, t h e purpose of t h e p r e s e n t paper i s t o make simultaneous measurements of temperature change i n i n t e r n a l f r i c t i o n , Young's modulus and e l e c t r i c a l r e s i s t i v i t y i n hypoeutectoid Gu-Al-Be a l l o y s i n o r d e r t o g i v e information on t h e i r transformation behavior and t o d i s c u s s on t h e r e s u l t s i n comparison with t h e t y p i c a l Cu-PJ-Ni and Cu-Zn-Al shape memory a l l o y s .
Table 1 ChexLcal composition and heat-treatment of a l l o y specinens.
1 ) Determined by means of electrical r e s i s t i v i t y measurement.
Article published online by EDP Sciences and available at http://dx.doi.org/10.1051/jphyscol:19824125
C4-768 JOURNAL DE PHYSIQUE
(a) CAB-1
\
(b) CAB-2
P i
I I
(c) C A B 3 l==l Fig. 1 Optical microstructures in alloys CAB-1, 2 and 3 quenched from 8 5 0 ~ ~ .
2. Experimenta1s.-The compositions, heat treatments and Ms-temperatures for five alloys chosen for the present
investigation are given in Table 1. Alloys CAB-1,2 and 3 were prepared by melting Cu-
&%Be, Cu-50%Al mother alloys and electrolytic copper
(99.9%~)
with high- frequency vacuum furnace. The ingots of 4kg were heated at 8 0 0 ~ ~ and subsequently hot-rolled to 5mm thick plates. The 7kg ingots of alloys CAN-6 and CZA-4 with the composition shown in Table 1 were obtained by air-melting electrolytic copper(99.9%
CU)
,
industrial pure aluminium(99.7%Al), pure zinc(99.99gn) and electrolytic nickel (99.7%~i) with high-freauencv furnace. The ingots were heated at"900°c and hot-forged and rolled to 5mm thick plates. Samples of 2mm x 10mm x 100mm were cut out of the rolled plates for the,
measurements of internal friction, Young s modulus and electrical resistivity. The betatizing temperatures and times are given in Table 1 and all the specimens were quenched into a 5kKOH solution bath held at 20°C.
The temperatye changes in internal friction and Young s modulus were
examined by the transverse vibration method at the resonance frequency of about IlcHz. The temperature change in electrical resistivity was measured by means of a d.c.-four terminal method with the same identical specimen as in the internal friction measurement.
Optical microstructures were observed in the same specimens used for the measurements. Change in surface relief with temperature was observed in alloy CAB-1 after electro-polishing at 80°C in a phosphoric-chromic acid bath.
Recoverable strain on heating due to shape memory effect was measured in the 0.5 mm thick samples of alloys CAB-1 and 3.
3. Results and Discussion.-Fig. 1 shows the optical microstructures in alloys CAB-1, 2 and 3 quenched from 8 5 0 ' ~ ~ observed at room temperature. The beta-phase was observed in alloys CAB-2 and 3 with the Ms-temperatures below room temperature.
On the other hand, alloy CAB-1 showed the martensite phase. The grain-refining effect by the beryllium addition was not remarkable.
Figs. 2 and 3 show the temperatxre changes in internal friction, Young's modulus and electrical resistivity in Cu-Al-Be, Cu-Al-Ni and Cu-Zn-Al alloys, respectively. Summary of results is shown in Table 2.
Internal friction peaks and anomalies in Young's modulus and electrical resistivity were observed around the transformation temperature in alloys CAB-1,2 and
3
as well as in alloys CAN-6 and CZA-4, respectively.The peaks in internal friction near the transformation temperature were very clear in alloys CAB-1,2 and 3 and the peak value(&-' ) increased with increasing alminium content. However, the value of Young's m o m u s decreased with increasing aluminium content, but the Young's modulus anomaly(~~) given by the depth of the Young's modulus versus temperature curves at the transformation temperature was
Temperature ("C ) Temperature ('C
v e r y small i n a l l o y s ChB-1 and 2 with lower aluminium
content. Such behavior w a s analogous t o t h e anomaly i n e l e c t r i c a l r e s i s t i v i t y ( ~ p ) and A p i n a l l o y CAB-2 was v e r y small a s shown i n Table 2.
The r e l a t i v e values of e l e c t r i c a l r e s i s t i v i t y a l s o decreased with i n c r e a s i n g aluminium content.
The temperature d i f f e r e n c e (AT) between t h e peaks i n t h e i n t e r n a l f r i c t i o n curves on h e a t i n g and cooling was l a r g e r i n a l l o y s CAB-1,2 and 3 t h a n i n a l l o y s CAN-6 and CZA-I+.
From t h e r e s u l t s , it was concluded t h a t t h e thermo- e l a s t i c m a r t e n s i t e
transformation occurred i n f a c t i n a l l o y s CAB-1,2 and 3 a s i n a l l o y s CAN-6 and GZA-4, b u t t h a t not all t h e
m a r t e n s i t e d i d not transform t h e r m o e l a s t i c d l y back t o beta-phase w i t h i n t h e experimental temperature range, because AE and AP, which a r e p r o p o r t i o n a l t o t h e volume f r a c t i o n of t h e thermo- e l a s t i c m a r t e n s i t e , a r e smaller i n a l l o y s CAB-1,2 and 3 than i n a l l o y s CAN-6 and CZA-4.
The following experiment was performed i n a n attempt t o confirm t h e shape memory e f f e c t i n t h e Cu-Al-Be a l l o y s . Specimens of a l l o y s CAB-1 and 3 were heated t o 80°C and 30°C r e s p e c t i v e l y , a f t e r bending a t O°C and -60°C, r e s p e c t i v e l y . Recoverable s t r a i n on h e a t i n g due t o shape Y'ig. 2 Changes i n i n t e r n a l f r i c t i o n , memory e f f e c t was measured and Young's modulus and e l e c t r i c a l t h e r e s u l t s a r e shown i n r e s i s t i v i t y with temperature i n Table 3. The given strait1 was
a l l o y s CAB-? ,2 and 3. comuletely recovered up t o
about 3% i n a l l o y CAB-3 b u t the f u l l y recoverable s t r a i n i n a l l o y CAB-1 was only about 1%. 'l'he s t r a i n s r e a l i z i n g two way memory e f f e c t were 2.7% i n CAB-1 and 4.2% i n CAB-3, r e s p e c t i v e l y .
A small piece(;?mm x 10mm x 3Omm) was c u t out of t h e specimen of a l l o y CAB-1 used f o r t h e above measurements i n order t o observe t h e change i n surface r e l i e f with temperature.
Fig. f+ i l l u s t r a t e s t h e photographs of s u r f a c e r e l i e f i n a l l o y CAB-1 a t 26OC and a t 80°C. A p a r t of t h e m a r t e n s i t e e x i s t i n g a t 26Oc which i s c a l l e d tranforming m a r t e n s i t e disappeared a t 80°C, but t h e o t h e r p a r t of t h e m a r t e n s i t e which i s c a l l e d non-transforming m a r t e n s i t e was v i s i b l e even a t 8 0 ' ~ . The l a t t e r m a r t e n s i t e d i d not transform back t o beta-phase within t h e experimental temperature range. It i s not
JOURNAL Dl? PHYSTQUE
o b v i o i ~ s whether I t i s 2 )Ion- t h e r n o e l s s t i c x a r t e n s i t c o r
., ther.rr.oelasLic m a r l e n s i t e v i t h a h i g h e r Ms-ccmper" Llwe.
I'hcrcf o r e , i t was con:iider.cd ~ h a L t h e s!nall A P a n u I E i n a l l o y s CAD-1 and 2 and t h e s n a l l r e c o v e r a b l e s t r a i n i n a l l o y CAB-1 were e x p l e i n c d a s r e s u l t i n g f r o n Lhe e x i s t e n c e of t h e non- t r a n s f o r n i n g mr t e n s i t e . Despite Lhe e x i s f e n c c of t h i s xcclrtensite, t h e i n t e r n a l f r i c t i o n peak a p p e a r e d c l e a r a l s o i n a l l o y s CA3-1,2 and 3, because i n l e r n a l f r i c t i o n i s o r j . g i n a l l y d e c e r r ~ n e d o n l y by t h e 1ocii.l a t o m i c c o n d i t i o n . The r e a s o n f'or ';he v e r y low v a l u e s of
G--'
i i n t h c b e t a - p h a s c r e g i o n and a l s o i n t h e r r ~ a r . t e n s i s e r e g i o n n a y 3 e c x p l a l n e d i n t h e r'ollowirig way: (1 ) s i r o n g d i s l o c a t i o n - p i r m i n g et'i'cct of t h e b c r y l l i i m . atoms i n b o t h b e t a - phase ~ n c ? m a r t e n s i t c p h a s e anti (2) d i . s l o c a t ion-pinning e f f e c t , or" irnpuricy atoms corlYnined I n t h e Cu-Be mother, . -
.'16.3 2:lages i n I n L e r n a l " r i c c i o n , a l l o y . ll'ron t h c s e a l l (1 ) Young's nodiilus azd e l e c c r l c a l seems t o be t h c most r c s i s t i v i t j r w i t h terriperacure i n CAN-6 predominani, i n t h c p r e s e n t and CXA-L. e x p e r i ~ e n t n l r c s u l t o . 'ihe
d e c e i l s ;.ire, however, s t i l l n o t kno:,m c l e a r l y .
.. .
. z d e 2 Summary o f r c s x l i s obzciined by m e a s w i n g i n t e r n 2 1 l ' r i c t , i o n , 'fo-ing's rnohlu-. and e i e c t r i c a l r c s l c t i v i t y .
I ) '['here x a s n o n - ~ r z n s f o r n 5 + n g m:ir:cr,si.te which remained i n ';he beta-phase r a n g e .
' a b l e 3 l e c o v e r a b l e s t r a i n on hcacing due zo shape nemory e f f e c t i n a l l o y s CAB-1 and 3.
Although t h e r e exisLed n o r ? - ~ r a n s f o r n i n g v a r t e n s i z e a s nentioyed above, t h e Y s -
i e x p e r a t u r e of Lhe L l e r m o e l a s t i c marbensitc i?
:he Cu-id-3e cilloy w d s given by t h e I'ollowing
l y I LV i expression.
Ks(OC)=638
-
43 x (w~:'.Al)-
302 x ( w t % ~ e )---
( I )Frorn he formula, i c was apparenz c h a t t h e
R
' Ms-temperaLure was e x t r e n e l y lowered bya d d i t i o n of beryllium and t h e e f f e c t of
R beryllium c o n ~ c n t on t h e Ks-temperncure was n b o x seven ~ i m e s :is much a s t h a t of aluminium c o n 5 e n ~ .
4. S m m r x . -The i n v e s t i g a t i o n was c a r r i e d ouL 260c on t h e m r t e n s i t i c L r a n s f o m a t i o n behavior i n
t h e Cu-Al-Be t e r n a r y cilloy system, i n comparison with the Cu-Al-Ni and Cu-Zn-Ail
2 ..
shape memory a l l o y s . The z h e r n o e l a s t i cm a r t e n s i t e t r a n s f o r m a t i o n appeared a l s o i n i h e
i
' //i:* Cu-Al-Se a l l o y s , while t h e v a l u e s i n Ap, AE
and r e c o v e r a b l e s L r a i n a s s o c i a c e d with t h e
- - -
Lransformacion were s n a l l . The pnenorlena were
/ / / '
explained by che e x i s ~ e n c c of the non- t r a n s f ' o r n i n g m a r t e n s i t e , which d i d n o iLransform t o beza-phase r e v e r s e l y w i t h i n t h e experimental temperaLut-e range. IIowever, r'ig.4 Photographs of s u r f a c e alLhough r e c o v e r a b l e s s r a i n was s m a l l i n a l l o y r e l i c f i n a l l o y CAS-1. CA3-1, bozh one way and Lwo way me~lory e f f e c t s
were r e a l i z e d i n t h e Cu-Al-Be a l l o y s . The e m p i r i c a l formula was d e r i v e d on t h e r e l a t i o n beLween he !.is-temperature i n Lhe >herno- e l a s L i c m a r ~ e n s i t e and he c o n L e ~ t of Lhe c o n s ~ , i t u t i o n a l elcments.
3 e f e r e n c e s
(1) C.M. Jackson, H.i.Wagner and R.J .'nfzsilewski: Nasa Report-SP5110.
(2) ~ . D e l a e ~ , i\.l)eruyctere, i','.Aernoudt and J .R.Roos : "Shape memory e f f e c t , super- e l a s l i c i - t y ~ i n d damping i n Cu-Zn-Al a l l o y s " 1ncr.a Keseach ~ e p o r t ( ~ r o j e c t ~ 0 . 2 3 8 ) ~ February 1978.
( j ) : ~ . C t s u k s and K.Shimiau: S c r i p t a !.let., 4(1970), 467.
( ~ ) ~ . ~ . ! , ~ i e l d and E.Gillam: ScripLa !kt., 6(1972) , I 157.
(5) ~ . ~ a b u r i and S.Nsnno: S c r i p t 3 Met., 8(1974), 1368.
( 6 ) 0 . ~ i c k e l : Z.Metall., k8(1957), 4.17. 49( 1958)
,
57.C 4 - 7 7 2 JOURNAL DE PHYSIQUE
(7) ~ . ~ . ~ r a w d z i g , F.T.Zurey and D.J .Mack: "An investigation of the mechanical properties and microstructures of heat treated aluminium bronzes."
Second Annual Report to Incra. June 1966.
