Journal of Materials Science and Engineering A 10 (3-4) (2020) 60-64 doi: 10.17265/2161-6213/2020.3-4.003
Influence of the Deep Cryogenic Treatment at the Stabilization of Martensitic Transformation Temperatures at the Smart Material Alloy Cu-14Al-4Ni
Emmanuel Pacheco Rocha Lima, Marcelo Nava and Pedro Cunha de Lima Faculdade do Gama, Universidade de Brasília, Gama 72444-240, Brasil Abstract: DCT (deep cryogenic treatment) is commonly used in industry to improve the wear resistance characteristics of steels, especially. However, there are just a few researches about the effects on non-ferrous metals. The purpose of this work was to investigate how DCT affects the properties of Cu-14Al-4Ni alloy treated at different soak time and submitted to thermomechanical cycling. A comparative experimental analysis was performed of the thermal properties of alloys obtained on a vacuum furnace, treated by DCT and thermomechanically cyclized. The results indicates that thermomechanical cycling promoted the appearance and growth of the martensitic phase γ'1, less ductile than the martensitic phase β'1, which together with the induced hardening produced an increase in transformation temperatures and microhardness. The higher the number of cycles, the greater these effects. The DCT promoted an increase in the intensity of the diffraction peaks corresponding to the phase β'1 and the maintenance of them during the thermomechanical cycling of the material, which indicates that the DCT stabilizes the martensitic phase β'1 and, consequently, caused a reduction and stabilization of the martensitic transformation temperatures and the microhardness, when compared to the untreated material. The longer the soaking time of DCT, the greater these effects.
Key words: DCT, SMA (shape memory alloy), Cu-Al-Ni alloy.
Nomenclature
DCT deep cryogenic treatment SMA shape memory alloy
EDS energy dispersive spectroscopy
XRD X-ray diffraction
T Mpeak peak temperature of martensitic transformation
T Apeak peak temperature of austenitic transformation
Greek Letters
β'1 martensitic phase
γ'1 martensitic phase
β1 high temperature phase
2θ diffraction angle
1. Introduction
The study of shape memory alloys (SMAs) has been explored in recent decades, due to their properties, such as mechanical work due to the shape change of the material when exposed to different temperatures [1]. SMAs are a group of metallic
Corresponding author: Emmanuel Pacheco Rocha Lima,
Ph.D., professor, research fields: phase transformation, shape memory alloys, metallurgy.
materials with the property to recover the original shape (shape memory effect) by imposing higher temperatures, due to inducing phase transformations in the material and thermoelastic properties of pseudoelasticity [2, 3].
Cu-Al-Ni system alloys have good thermomechanical properties, good shape recovery and higher hysteresis. Another factor that justifies the use of this type of system is its low cost of material acquisition and certain facilities observed at the alloy’s manufacturing, reducing the cost of production in relation to Ni-Ti based systems [4, 5].
One of the factors that reduce the application of Cu-Al-Ni alloys is the reduction of the stabilization capacity of the martensitic/austenitic phases.
Different processes for the elaboration of SMA have been studied along the techniques of thermomechanical treatment and addition of refining elements in order to reduce the level of complexity of the austenite/martensite transformation, like the DCT (deep cryogenic treatment) [6-8].
DCT is treatment that consists of using temperatures closer to liquid nitrogen temperature (-196°C) and subsequent stabilization at room temperature, in order to obtain certain properties, such as high wear resistance, toughness, hardness and compressive residual stress, among others, and the use of this process is increasing [9]. However, further
D DAVID PUBLISHING
research is rtime and ththose relatedthe most apponly would but also thexplored, wthe loss of sassociated to
2. Experim
The alloyfurnace of 2The meltesolidificationcasting, the 15 min. Theof X-ray compositionapproximate
The ingotwires with samples wercooling and 2h, 12h and
The wireswere submperformed wgauge, to staand 500 cycsubmitted tosure that the
After treanalyzed bfluorescenceconfocal lmicroscopy,measuremen
3. Experim
In order toto verify ththe produceEDS (chemperformed.
The EDS per region compositionchemical cotransformatimandatory. seen in Tabl
InfluenTrans
required in rehe alterations d to the CuApropriate metthe low cost
he improved with emphasis
shape recoveo the stabiliza
mental Setu
y was vacuu4 kVA, using
ed alloy wn, it was wingot was ho
en, the alloy fluorescence
n. Then, theely), in order ts were secti1 × 0.8 × 6re cooled at heating, and
24h. s (samples) w
mitted to with a plier andardize thecles. During to temperatur
e initial shapeatment and by XRD e, differentlaser micro, Vickers mnt.
mental Resu
o determine the uniformit
ed ingot, X-rmical dispers
microanalysisuggests u
n of the momposition inion tempera
The EDS mle 1.
nce of the Desformation Te
elation to the obtained int
AlNi system,thod of elabot must be a s
properties s to the capacry capacity, ation of marte
up
um melted g a crucible owas chill-cawater-cooled omogenized was submitte
e to verify ingot was to standardizoned by elec6 mm dimen-196°C at ra
d kept at this
were embed thermomechand a 1° p
e process, exthe cycling, tres higher the was recover
cycling, the(X-ray difftial scanninoscopy, sca
microhardness
ults
the chemical ty of the mray fluorescension energy
is, performeduniformity omelted alloy.nduce changetures, and microanalysis
ep Cryogenicemperatures
different soakto the SMA , associated woration. Thus,selection critcould be bcity of inhibiwhich is direensite phase.
in an inducof silicon carbast and, aat 25°C. A
at 950°C, dued to an anal
y the chemhot-rolled (
ze the thicknectroerosion innsions. Diffe
ates of 20°C/hs temperature
in one side hanical cyclprecision graecuting 100, the samples whan 120°C toed. e samples wfraction), Xng calorimeanning elec and grain
compositionmicrostructurence analysis
analysis) w
d at several poof the chem. Variations es in martenthis control
s results can
c Treatment aat the Smart
king and
with , not eria, etter iting ectly
ction bide. after
After uring lysis
mical (2%, ess. n 36 erent h on e for
and ling, aded 250
were o be
were X-ray
etry, ctron
size
n and e of
and were
oints mical
on nsitic l is n be
Tab
T
4Niandpha
Fig.beta500 500
Tthe the
at the Stabiliz Material Allo
ble 1 Chemical
Element
Cu
Al
Ni
The results ofi alloy presen
d AlCu3 typease β1. This re
. 1 Results ofatized samplescycles; (c) samcycles.
Thermomechamartensitic appearance (
zation of Martoy Cu-14Al-4N
l composition o
Conc
f diffractomented three phae, respectivelesult can be s
f the XRD anas; (b) samples mples with DC
anical cyclingphase β'1, w(increase of i
tensitic Ni
of the Cu-14Al
centration (weig
82.3 14.0 3.7
etric analysis ases: martensly, and high een in the Fig
alyses of: (a) awithout DCT
CT time of 2h a
g induced thewhich appears
intensity) of t
61
l-4Ni. ght %)
of Cu-14Al-itic γ'1and β'1temperature
g. 1.
as melted andafter 100 and
and 24 h after
e decrease ofs at 43°, andthe γ´1 phase
-1, e
d d r
f d e
62
(also martenphase, it cauobserved thtemperaturesrecoverabilit
After the showed thephasewhich stabilized ththe γ'1 phase
The samanalysis in sbetween 0°submitted theating/cooltemperature toverify thetransformatieach sample
Fig. 2 Compatemperatures
Fig. 3 Cotransformatiowithout DCT
The tranforward andof thermominput of enmemory efftransformatithe DCT sotemperatures
InfluenTrans
nsitic). Since uses the graduhrough the s, microharty. greater amo
e higher intprovokes the
he β'1 martense.
mples were steps of 40°CC and 120°to differentialing rate o
range. Throe phase transion enthalpiee. These resul
arative graph os for samples cy
omparative gon temperatur.
nsformation d reverse dire
mechanical cynergy is reqfect. DCT caion temperatuoaking time, s. This behav
nce of the Desformation Te
it is less duual loss of thrise of the
dness and
ount of cyclintensity at 65e loss of shapsitic phase at
submitted toC/min in a teC. Subsequeal thermal aof 15°C/minough the testsformation te
es and the hylts are shown
of peak austeniycled with and
graph of pres for sample
temperaturesection, increaycles increasequired to proaused a reducures. In addthe lower th
vioral change
ep Cryogenicemperatures
uctile than thee memory efe transforma
loss of sh
ng, the γ'1 ph5°. This is
pe recovery. D43°, suppres
o DSC theremperature raently, they wanalysis usinn in the st it was possemperatures, ysteresis levein Figs. 2 an
itic transformad without DCT
peak martenes cycled with
s, both in se as the num
es, thus a greoduce the shction in mate
dition, the lonhe transformae caused by D
c Treatment aat the Smart
e β'1 ffect, ation hape
hase the
DCT ssing
rmal ange were ng a same sible
the el of d 3.
ation
T.
nsitic
and
the mber eater hape erial nger ation DCT
mayinteof resp
Taustsoakundmat
Sintemicimpmayway
Tab
no
no
no
DC
DC
DC
DC
DC
DC
DC
DC
DC
Tof cof mdefo
Mlasewheshowithpolynee
F5), mictherregato omarThiof tin th
It
at the Stabiliz Material Allo
y be relatedensity present
the orderedponsible for tThe hysteresitenitic peakking time inc
der some cterial (Table 2Since hystereernal dampincrostructural purities and y have somey, causing thi
ble 2 Peak tran
Samples
DCT 100× DCT 250× DCT 500×
CT 2h 100× CT 2h 250× CT 2h 500× CT 12h 100× CT 12h 250× CT 12h 500× CT 24h 100× CT 24h 250× CT 24h 500×
The significancycles increasmartensite va
formations anMicroscopic er microscopyere the wirewing, in all sh grains shygonal morph
edle aspects, wFrom the pres
it is not pocrostructural rmomechanicarding the saobserve a notirtensite needlis fact may bethe peaks corhe XRD resut was not p
zation of Martoy Cu-14Al-4N
d to the higted in XRD wd phase β'the shape mems (difference
k temperaturcreases, with conditions, 2). esis in SMAng and this t
defects, sucdisagreemen
how acted onis increase in
nsformation tem
T Mpeak (°C) T
66.12
78.25
89.53
51.02
55.73
65.16
36.09
40.05
45.87
26.05
30.26
34.42
nt decrease inses may be reariants, caused heating. analysis wasy in the crosses were sectsamples, marthowing well hology, withwithout poressented microsossible to obchanges in
cal cycling ample submitticeable increales as the DCe related to thrresponding t
ults. possible to o
tensitic Ni
gher occurrewith increasin
1 (the phamory effect). between mares) increasevalues greatecompared t
As is directlto various phch as grain nts, cryogenn these defecmaterial hyst
mperatures. T Apeak (°C) H
80.21
85.12
95.34
71.42
73.12
80.62
62.87
65.53
67.72
56.82
60.22
63.10
n hysteresis aelated to the ed by succes
s performed s section of thtioned by eltensitic matri
defined coh equiaxial tens or inclusionscopy resultsbserve morpthe samples
performedted to DCT, ase in the thic
CT soaking timhe increase into the β'1 pha
bserve morp
ence (higherng DCT time)se stronger,
artensitic andes as DCTer thandoubleto untreated
y related tohenomena in
boundaries,nic treatmentcts in such ateresis.
Hysteresis (°C)
14.09
6.87
5.81
20.40
17.39
15.46
26.78
25.48
21.85
30.77
29.96
28.68
as the numberreorientationsive material
in confocalhe laminationlectroerosion,x (β'1 phase),
ontours withndency, withs. (Figs. 4 and
phological ors due to the. However,it is possibleckness of theme increased.n the intensityase presented
phological or
r ) ,
d T e d
o n , t a
r n l
l n, , ,
h h
d r e , e e . y d
r
microstructuthermomech
The grairegardless osignificant cand 230 μmcycling whe
Fig. 4 Confwithout DCT
Fig. 5 Confoc24h DCT, wit
Fig. 6 Vickthermomecha
For the Vdeviations oeach samplemicrohardnedeviation (Fincrease withsamples sumicrohardne
InfluenTrans
ural changes hanical cyclinn size meaof the soakchanges in th
m), keeping tncompared to
focal microgra, with (a) 100 c
cal micrographth (a) 100 cycle
kers micro anically cycled
Vickers microhof 15 indentae were calcuess results aFig. 6), the mh the increaseubmitted to ess values with
nce of the Desformation Te
in the samng performed.asurements sking time, dhe grain’s sizthe same beho alloy witho
aphy of the Ccycles and (b) 5
h of the Cu-14es and (b) 500
hardness testd samples with
hardness, meations in 3 diulated. Analyzand consideri
microhardnesse of the numb
DCT, thh increasing n
ep Cryogenicemperatures
mples due to . show the Ddid not prodze (between havior relate
out DCT.
Cu-14Al-4Ni a500 cycles.
4Al-4Ni alloy, cycles.
t results of and without D
eans and standistinct regionzing the Vicing the stand presents a smber of cycles.
his increase number of cy
c Treatment aat the Smart
the
DCT, duce 200 d to
alloy,
with
the
DCT.
dard ns of ckers dard mall . For
in ycles
is macc
Insmawithchaof resp
4. C
Tthersubthermai
(manthe andmic
(2diffcorrmaicyclthe
(mictherrelaphamarshapDC
(4timsamtemtranintemarmiccryotheshys
(grai
Ac
Tsupdo D
at the Stabiliz Material Allo
minimized (tording to the n addition, thaller the mich increasing
ange due to Dthe more duponsible for t
Conclusion
This work irmomechanicmitted to Drmomechanicin conclusion1) Based onnufacturing pα-phase, hig
d producedcrostructure o2) DCT indufraction peakresponding tointenance of ling of the maordered ortho3) DCT prod
crohardness rmomechanicated to the staase of the Alrtensitic phaspe memory eT, the greater4) Related toe of the DCT
mples, the gremperatures ofnsformation. Ternal dampingrtensite platecrostructural ogenic treatmse defects interesis of the5) DCT didin sizes.
knowledgm
The authors port of FAPDDistrito Fede
zation of Martoy Cu-14Al-4N
the rate of mnumber of cy
he longer thecrohardness o
number of DCT must be ructile martenthe shape mem
ns
investigated cal changes aDCT, at dically cycled ns are: n the diffracprocess supprh copper hard
d an ortof AlCu3 (β'1) uced the incres (increase oo the phase (βf these durinaterial, indicatorhombic maduced a sens
of the mcal cycling. abilization of lCu3 type (β'se (γ´1) and reffect. The lor these effect
o the hysteresT, for the theeater the difff the direct This behaviog of the mate
es) and this, defects, in
ment may havn order to ca material.
d not produc
ments
gratefully acDF (Fundaçãral).
tensitic Ni
microhardnesycles is smalle DCT soakiof the mater
cycles. Thirelated to the
nsitic phase mory effect [
the microstrat the Cu-14Afferent soakin different
ction analysressed the predness intermethorhombic type, typical
ease in the intf the volumeβ'1) and, consng the thermting that the Dartensitic phassitive stabilizmaterial suThis behav
f the orthorho'1), more ducresponsible foonger the soas.
sis, the higherermomechanference betwe
and reverseor is directly rerial (frictionto several ph
such a wve acted in sause this inc
ce significant
cknowledge tão de Ampar
63
ss increasingler). ing time, therial increasesis behaviorale stabilizationβ'1 which is10].
ructural andAl-4Ni alloy
k time, andcycles. The
is, the usedecipitation ofetallic phase,
martensiticl of SMA. tensity of the
etric fraction)sequently, the
momechanicalDCT stabilizedse (β'1). zation of theubmitted tovior may beombic orderlyctile than theor the alloy’saking time of
r the soakingically cycledeen the peake martensiticrelated to the
n between thehenomena in
way that thesome way increase in the
t changes in
the financialro a Pesquisa
3
g
e s l n s
d y d e
d f , c
e ) e l d
e o e y e s f
g d k c e e n e n e
n
l a
Influence of the Deep Cryogenic Treatment at the Stabilization of Martensitic Transformation Temperatures at the Smart Material Alloy Cu-14Al-4Ni
64
References
[1] Balo, S. N., and Ceylan M. 2002. “Effect of Be Content
on Some Characteristics of Cu-Al-Be Shape Memory
Alloys.” Ph.D. thesis, Firat University.
[2] Otsuka, K., and Wayman M. 1998. Shape Memory
Materials. Cambridge: Cambridge University Press.
[3] Isalgue, A., Fernandez, J., Torra, V., and Lovey, F. C.
2006. “Conditioning Treatments of Cu-Al-Be Shape
Memory Alloys for Dampers.” Ph.D. thesis, Dep. Física
Aplicada UPC, Campus Nord.
[4] Liu, J. 2016. “Microstructure and Properties of Cu-3Ti-1Ni
Alloy with Aging Process.” Ph.D. thesis, Shaanxi Key
Laboratory of Electrical Materials and Infiltration Technology.
[5] Juan, J. N. 2009. “Nanoscale Shape Memory Alloys for
Ultrahigh Mechanical Damping.” Nat. Nanotech 4: 415-9.
[6] Vinothkumar, T. S., Rajadurai, A., and Kandaswamy, D.
2015. “Effect of Dry Cryogenic Treatment on Vickers
Hardness and Wear Resistance of New Martensitic Shape
Memory Nickel-Titanium Alloy.” European Journal of
Dentistry 4: 513-7.
[7] Baldissera, P., and Delprete, C. 2008. “Deep Cryogenic
Treatment: A Bibliographic Review.” The Open
Mechanical Engineering Journal 2: 1-11.
[8] Vinothkumar, T. S., Prabhakaran G., Rajadurai, A., and
Kandaswamy, D. 2016. “Mechanical Behavior of Deep
Cryogenically Treated Martensitic Shape Memory
Nickel-Titanium Rotary Endodontic Instruments.”
European Journal of Dentistry 2: 183-7.
[9] Bensely, A., et al. 2006. “Enhancing the Wear Resistance
of Case Carburized Steel by Cryogenic Treatment.
Cryogenics.” Materials Characterization 5: 485-91.
[10] Lima, P. C. 2018. “Estudo do efeito da adição de titânio no tamanho de grão, nas temperaturas de transformação de fase e no módulo elástico da liga Cu-14Al-4Ni com efeito memória de forma obtida por fusão a arco e solidificação rápida a vácuo.” Ph.D. thesis, Universidade de Brasília. (in Portuguese)