me als
A icle
Cha ac e izing he Solde ing Alloy Type Zn–Al–Cu and S udy
o Ul asonic Solde ing o Al7075/Cu Combina ion
Roman Kolenak 1, Igo Kos olny 1,*, Ja omi D apala 2, Paulina Babinco a 1and Ma in Sahul 1


Ci a ion: Kolenak, R.; Kos olny, I.;
D apala, J.; Babinco a, P.; Sahul, M.
Cha ac e izing he Solde ing Alloy
Type Zn–Al–Cu and S udy o
Ul asonic Solde ing o Al7075/Cu
Combina ion. Me als 2021,11, 27.
h ps://doi.o g/10.3390/me 11010027
Recei ed: 9 Decembe 2020
Accep ed: 22 Decembe 2020
Published: 25 Decembe 2020
Publishe ’s No e: MDPI s ays neu-
al wi h ega d o ju isdic ional claims
in published maps and ins i u ional
a ilia ions.
Copy igh : © 2020 by he au ho s. Li-
censee MDPI, Basel, Swi ze land. This
a icle is an open access a icle dis ibu ed
unde he e ms and condi ions o he
C ea i e Commons A ibu ion (CC BY)
license (h ps://c ea i ecommons.o g/
licenses/by/4.0/).
1Facul y o Ma e ials Science and Technology T na a, Slo ak Uni e si y o Technology in B a isla a, Jána
Bo u No. 2781/25, 917 24 T na a, Slo akia; [email p o ec ed] (R.K.);
[email p o ec ed] (P.B.); [email p o ec ed] (M.S.)
2
FMT—Facul y o Ma e ials Science and Technology, Technical Uni e si y o Os a a, 17. Lis opadu 15, 708 33
Os a a, Po uba, Czech Republic; ja omi [email p o ec ed]
*Co espondence: igo [email p o ec ed]; Tel.: +421-918746159
Abs ac :
The aim o he esea ch was o cha ac e ize he solde ing alloy ype Zn–Al–Cu and s udy he
luxless ul asonic solde ing o he combina ion o aluminum alloy ype Al7075 wi h coppe subs a e.
The Zn–Al–Cu solde is o he close- o-eu ec ic ype wi h wo phase ans o ma ions: he eu ec ic
ans o ma ion a 378
◦
C and he eu ec oid ans o ma ion a 285
◦
C . The solde mic os uc u e is
o med o a ma ix composed o he solid solu ions o aluminum (Al) and zinc (Zn) in which he
coppe phases CuZn
4
and CuAl
2
a e p ecipi a ed. The shea s eng h o he solde ing alloy ype
Zn5Al wi h coppe addi ion eaches alues om 167 o 187 MPa and i depends on he coppe con en
in he solde . The bond wi h aluminum alloy ype Al7075 is o med due o he solubili y o Al in
zinc solde a he o ma ion o solid solu ion Al. Con a y o his obse a ion, he bond wi h he
coppe subs a e is in his case o med due o he in e ac ion o zinc and aluminum wi h he coppe
subs a e. Two new in e me allic phases, namely Al(Cu,Zn)
2
and Cu
3.2
Zn
0.7
Al
4.2
, we e o med.
The a e age shea s eng h o Al7075/Zn5Al3Cu/Cu join s a ained was 134.5 MPa. Fo compa ison,
he Cu/Zn5Al3Cu/Cu join a ained an a e age shea s eng h o 136.5 MPa.
Keywo ds: solde ing; ul asonic; in e me allic compounds; shea s eng h
1. In oduc ion
Ma e ials used in ce ain indus ial applica ions a e equi ed o be ligh , s ong,
and elec ically conduc i e a he same ime. These condi ions a e me in he case o
ma e ials such as coppe and aluminum. In he case o Cu/Al join s, many o he p ope ies
o bo h ma e ials a e u ilized. Howe e , he ab ica ion o a sound join o hese wo
ma e ials is a a he icky ma e due o physical di e ences be ween he Cu and Al
elemen s. Di e en welding echnologies may be used o joining hese me als, such as
ic ion, ic ion s i welding, lase o cold oll welding [
1
–
5
]. Howe e , solde ing is also a
sui able echnology o joining hese me als. Mo eo e , solde ing can be applied also o
he ab ica ion o p oduc s wi h in ica e shapes as well as o mass p oduc ion [6,7].
One possible me hod o solde ing he Cu/Al combina ion is by he applica ion o
zinc solde s. This conce ns solde s alloyed wi h one o mo e elemen s. Zn-based solde s
a e a sui able op ion also in iew o hei ela i ely low p ice and capabili y o eac wi h
he su ace o bo h Al and Cu. The addi ion o a small amoun o sui able alloying elemen s
lowe s he mel ing empe a u e o hese solde s and enhances he solde abili y. Resea ch
on Zn-based solde s has been ca ied ou by many au ho s [
8
–
14
]. In hei wo ks, hey
ha e mainly used solde s based on Zn–Al o Zn–Sn wi h he addi ion o o he elemen s.
Thei esea ch was de o ed o he e ec o he alloying elemen s on he mic os uc u e,
o ma ion o in e me allic phases, o he s eng h o di e en combina ions o me als o
ce amics, and o he s udy o he co osion p ope ies o he solde s.
Me als 2021,11, 27. h ps://doi.o g/10.3390/me 11010027 h ps://www.mdpi.com/jou nal/me als
Me als 2021,11, 27 2 o 17
Feng, J. e al. [
15
] ocused also on he e ec o he Al con en on he p ope ies o
Zn–Al solde when ab ica ing Cu/Al join s. In hei s udy, a small amoun o Ce was
added o he solde and hey assessed i s e ec upon he solde abili y, he mic os uc u e
o he Zn22Al solde , he mechanical p ope ies o he join , and he s uc u e o he laye
o med in he bounda y o he Cu/Al join . Ma e ials such as Al alloy ype 1060 and pu e
coppe we e used in hei expe imen s and au oma ic solde ing wi h an oxy-ace ylene
lame was applied. The Ce con en a ied om 0.01 o 1 w . %.
The Zn(4–6)Al(1–5)Cu alloy des ined o highe applica ion empe a u es was de-
signed wi h a liquidus poin be ween 382 and 402
◦
C . The inc eased Al con en imp o es
he sp eadabili y and nominal elec ic esis ance bu he Cu con en does no signi ican ly
a ec hese p ope ies. The added elemen s inc ease he ha dness and ensile s eng h.
The s udy e ealed he a o able p ope ies o Zn–Al–Cu alloys such as good solde abili y,
low nominal elec ic esis ance, and good mechanical p ope ies [
16
]. In [
17
], Zn–Al–Cu
based alloys des ined o highe applica ion empe a u es we e s udied, namely he ZCA34
(Zn3Cu4Al), ZCA35 (Zn3Cu5Al), and ZCA36 (Zn3Cu6Al) alloys. The s eng h o hese
alloys was measu ed by SPT (shea punch es ) in he empe a u e ange om 25 o 225
◦
C .
Loading wi h he o ce o 20 kN a he loading a e o 0.25 mm
·
min
−1
was applied. A e
loading, he shea s eng h o he s udied specimens was de e mined. In [
18
], he au ho s
s udied he eac ions be ween he solde ypes Zn4Al and Zn4Al1Cu o highe applica ion
empe a u es and coppe subs a e. The mel ing poin o hese solde s was 380 and 381
◦
C,
espec i ely. The addi ion o 1 w . % Cu esul ed in educed ac i a ion ene gy, inc eased
g ow h o he IM (in e me allic) phases o Cu–Zn, and a educed e osion a e o he Cu sub-
s a e. Fei Xing e al. also esea ched he solde ing o Cu using Zn-based solde s [
19
]. Thei
esea ch included solde ing wi h Zn–Sn–Cu–Bi solde s a he empe a u e o 450
◦
C wi h
he applica ion o lux ype ZnCl
2
/NH
4
Cl a di e en eac ion imes om 10 o 90 s. They
obse ed he p esence o in e me allic phases such as
ε
-CuZn
5
,
γ
-Cu
5
Zn
8
, and
β
-CuZn in
he bounda y wi h he Cu subs a e. The shea s eng h o he o e lapped join s a ained
alues om 51.6 o 76.5 MPa.
The aim o ou s udy consis ed in he solde ing o Cu and Al subs a es by a luxless
p ocess in ai wi h ul asound assis ance. The con ibu ion p esen s he cha ac e iza ion o
Zn–Al-based solde wi h Cu addi ion. Solde s wi h 1, 2, and 3 w . % Cu we e assessed by
ICP-AES (induc i ely coupled plasma-a omic emission spec ome y) and DSC (di e en ial
scanning calo ime y) analyses and ensile s eng h measu emen s. The solde ed join s
p ope we e ab ica ed using solde ype Zn5Al3Cu wi h 3 w . % Cu. These join s we e
subjec ed o SEM/EDX analysis and a shea s eng h es .
2. Ma e ials and Me hods
A e de e mina ion o he weigh p opo ions o he p epa ed expe imen al alloy,
he weighing o indi idual componen s was pe o med. Ma e ials wi h a high pu i y o 4N
we e used as inpu componen s o solde manu ac u e.
Solde manu ac u e in he as-cas condi ion was pe o med in a acuum o en (PZP
KOMPLET a.s., Dob uška, Czech Republic). The p ocedu e was as ollows: he calcula ed
cha ges o solde componen s we e placed in a g aphi e boa . The boa wi h he cha ge was
placed in a ube made o siliceous glass 50 mm in diame e . The ube was hen inse ed
in o a ho izon al acuum esis ance o en so ha he boa was si ua ed in he hea ing zone.
The ube could, i necessa y, be lushed wi h A by he lange on i s inle and he ou le on i s
end. In he case o Zn-based solde s, i is mo e sui able o p epa e hem a A o e p essu e
due o solde e apo a ion. The cha ge was mol en a he speci ied empe a u e. Some
me als a e well soluble in he base ma ix. The dissol ing and homogeniza ion o he solde
componen s las ed o app oxima ely one hou , un il he mel unde A shielding was
eely cooled down. A e emo al om he o en, he o med alloy was again mel ed in a
g aphi e c ucible, and a e ho ough s i ing, i was cas o a g aphi e boa whe e i was
cooled down apidly.
Me als 2021,11, 27 3 o 17
Th ee solde ing alloys based on Zn5Al, wi h 1, 2, and 3 w . % Cu we e p epa ed.
The chemical composi ion o hese alloys is gi en in Table 1.
Table 1.
Composi ion o Sn–Sb–Ti alloy and he esul s o chemical analysis done by he he ICP-AES
me hod [w . %].
Sample Cha ge (w . %) ICP-AES (w . %)
Zn Al Cu Zn Al Cu
Zn5Al1Cu 94 5 0.1 93.9 ±0.6 4.71 ±0.3 1.1 ±0.2
Zn5Al2Cu 93 5 0.2 93.1 ±0.6 4.82 ±0.4 2.01 ±0.3
Zn5Al3Cu 92 5 0.3 92.3 ±0.7 4.65 ±0.4 3.08 ±0.2
Chemical analysis o he p epa ed alloys was pe o med by he a omic emission
spec ome y me hod wi h induc ion coupled plasma (ICP-AES, SPECTRO Analy ical
Ins umen s GmbH, Kle e, Ge many). The analysis was ca ied ou on he ins umen
ype SPECTRO VISION EOP (SPECTRO Analy ical Ins umen s GmbH, Kle e, Ge many).
The samples o alloys des ined o ICP-AES analysis we e dissol ed in sui able chemical
solu ions o acid and bases. The analysis p ope was pe o med on he emission a omic
spec ome e (SPECTRO Analy ical Ins umen s GmbH, Kle e, Ge many) wi h a pneuma ic
a omize and Sco ’s a omizing chambe .
Tes pieces o he ensile s eng h es we e hen p epa ed om he solde ing alloys
(Figu e 1a). The dimensions gi en in Figu e 1a a e in mm.
Figu e 1. Schema ic p esen a ion o es pieces (uni : mm). (a) Tensile s eng h es piece; (b) assembly o solde ed join s.
Subs a es o he ollowing ma e ials we e used o he expe imen s:
•
me allic Cu subs a e o 4N pu i y in he shape o discs wi h dimensions Ø 15 mm
×
2 mm,
•me allic Al7075 subs a e in he shape o discs wi h dimensions Ø 15 mm ×2 mm.
The scheme o he solde ed join s is shown in Figu e 1b.
The solde ed join s we e ab ica ed using a ho pla e wi h he mos a ic empe a u e
con ol. The Si subs a e was placed on he ho pla e and hen he solde hea ed o he
solde ing empe a u e was placed on i . Solde ing was pe o med using an ul asonic
equipmen ype Hanuz UT2 (HANUZ s. .o. No e Mes o nad Vahom, Slo akia) wi h he
pa ame e s gi en in Table 2. Solde ac i a ion was ealized ia an encapsula ed ul asonic
ansduce consis ing o a piezo-elec ic oscilla ing sys em and a i anium sono ode wi h
he end ip diame e o Ø 3 mm. The solde ing empe a u e was app oxima ely 20
◦
C
abo e he mel ing poin o he solde ing alloy. The solde ing empe a u e was checked by
con inuous empe a u e measu emen on he ho pla e using a NiC /NiSi he mocouple.
The ul asonic powe was ac i a ed o 5 s. Solde ing was ealized wi hou he use o lux.
A e ul asound ac i a ion, he edundan oxide laye on he su ace o he mol en solde
was emo ed. A simila p ocess was pe o med also wi h he o he subs a e. Then, bo h
subs a es wi h mol en solde we e laid on each o he and hus he solde ed join was
o med. The schema ic ep esen a ion o his p ocess is shown in Figu e 2and he se -up
scheme o ul asonic solde ing is shown in Figu e 3.
Me als 2021,11, 27 4 o 17
Table 2. Solde ing pa ame e s.
Ul asound powe 400 (W)
Wo king equency 40 (kHz)
Ampli ude 2 (µm)
Solde ing empe a u e 410 (◦C)
Time o ul asound ac i a ion 5 (s)
Figu e 2. Schema ic ep esen a ion o he solde ing p ocess in he p esence o ul asonic powe .
Figu e 3. Se -up scheme o ul asonic solde ing.
Me allog aphic p epa a ion o specimens om he solde ed join s was ealized by he
s anda d me allog aphic p ocedu es used o specimen p epa a ion. G inding was pe -
o med using SiC eme y pape s wi h 240, 320, and 1200 g ains/cm
2
g anula i y. Polishing
was pe o med wi h diamond suspensions wi h g ain size 9, 6, and 3
µ
m. Final polishing
was pe o med using polishing emulsion ype OP-S (S ue s) wi h 0.2 µm g anula i y.
The solde mic os uc u e was s udied using scanning elec on mic oscopy (SEM)
on mic oscopes o ype TESCAN VEGA 3 (Tescan O say Holding, B no, Czech Republic)
and JEOL 7600 F (JOEL L d., Tokyo, Japan) wi h an X- ay mic o-analyze ype Mic ospec
Me als 2021,11, 27 5 o 17
WDX-3PC (Mic ospec L d., Pe e bo ough, NH, USA) o pe o ming he quali a i e and
semi-quan i a i e chemical analysis.
Fo iden i ica ion o he phase composi ion o he solde , X- ay di ac ion analysis
was used, pe o med on an XRD di ac ome e ype PANaly ical X’Pe PRO (Mal e n
Panaly ical L d., Mal e n, UK) wi h solde specimens o dimensions 10 mm
×
10 mm
×
2 mm. S ep size pa ame e was 0.013◦and scan s ep ime pa ame e was 29.07 s.
Di e en ial scanning calo ime y, o also di e en ial compensa ion calo ime y, is
a me hod in which he he mal p ope ies o ma e ials a e examined. The DSC analysis
o he Zn–Al–Cu solde s was pe o med on equipmen ype Ne zsch STA 409 C/CD
(NETZSCH-Ge ä ebau GmbH, Selb, Ge many) unde shielding wi h A gas wi h 6N pu i y.
To de e mine he mechanical p ope ies o he solde ed join s, he shea s eng h es was
pe o med. The measu emen was pe o med on he ollowing join :
Coppe in he shape o discs wi h dimensions Ø 15 mm
×
3 mm/squa e o Al7075
alloy wi h dimensions 10 mm ×10 mm ×3 mm.
The schema ic ep esen a ion o he specimen is shown in Figu e 4a. The shea s eng h
was measu ed on a e sa ile es ing equipmen ype LabTes 5.250SP1-VM (Labo ech L d.,
P aque, Czech Republic). To change he di ec ion o he axial loading o ce applied on he
es specimen, a special jig was used wi h he de ined shape o he es specimen
(Figu e 4b)
.
This shea ing jig ensu es a uni o m loading o he specimen by shea in he plane o he
solde and subs a e bounda y.
Figu e 4.
Schema ic p esen a ion o shea s eng h measu emen . (
a
) Specimen o shea s eng h es (uni : mm); (
b
) scheme
o special jig.
3. Resul s
3.1. DSC Analysis
To de e mine he mel ing poin o he solde , DSC analysis was applied. The DSC
cu e o solde ing alloys o ype Zn–Al–Cu ypically has wo basic peaks. The i s peak
co esponds o eu ec oid ans o ma ion and he second p onounced peak co esponds o
eu ec ic ans o ma ion (Figu e 5). Following he Zn–Al bina y diag am, he empe a u e
o eu ec oid ans o ma ion is a ound 278
◦
C (Figu e 6). Acco ding o [
20
], he ollow-
ing eac ion akes place a his empe a u e: Al- ich cc (Al) + hcp (Zn)
↔
Zn- ich cc
(Al). I is ob ious om he DSC cu e in Figu e 7 ha he addi ion o Cu o he solde
inc eases he empe a u e o his ans o ma ion o app oxima ely 285
◦
C . On he con a y,
he empe a u e o eu ec ic ans o ma ion, which acco ding o he bina y diag am equals
381
◦
C (Figu e 6), is sligh ly educed wi h he addi ion o Cu o he solde ing alloy. A 2
w . % Cu, he maximum empe a u e o he second peak is 379.0
◦
C , and a 3 w . % Cu,
he maximum empe a u e o ha peak is 378.4
◦
C . Since he main base o he Zn5Al solde
is close- o-eu ec ic, a he empe a u e a ound 381
◦
C , i should be comple ely mol en. Bu
he addi ion o coppe o he solde shi s he end empe a u e owa ds highe alues and
ex ends he lowe sec ion o he peak (Figu e 5), whe eas in he case o Zn5Al2Cu and
Zn5Al3Cu solde s, a hi d peak is c ea ed. The Zn5Al1Cu solde is o ally mol en a he
empe a u e o 383.9
◦
C , whe eas in he case o he Zn5Al3Cu solde , mel ing e mina es a
386.7
◦
C . Table 3shows he measu ed solidus and liquidus empe a u es o hese solde s.
The solde ing empe a u e is usually selec ed app oxima ely 20
◦
C abo e he mel ing poin
o he solde ing alloy, so he solde ing empe a u e applied in he expe imen s was 410
◦
C .

Me als 2021,11, 27 6 o 17
Figu e 5.
DSC cu es o solde ing alloys: (
a
) Zn5Al1Cu; (
b
) Zn5Al2Cu; (
c
) Zn5Al3Cu, a he hea ing a e o 1 K
·
min
−1
.
* manually ex apola ed poin .
Figu e 6. The bina y diag am o Al–Zn [20].
Me als 2021,11, 27 7 o 17
Figu e 7. The phase diag am o Al–Zn–Cu o he concen a ion o 3 w . % Cu [20].
Table 3. Solidus and liquidus empe a u es o Zn-Al-Cu solde s.
Solde Solidus (◦C) Liquidus (◦C)
Zn5Al1Cu 377.7 383.9
Zn5Al2Cu 371.8 386.1
Zn5Al3Cu 370.2 386.7
3.2. Mic os uc u e o Solde s Type Zn–Al–Cu
The mic os uc u e was s udied by he SEM echnique in obse ing mode BSE (Back-
sca e de ec o ). In he BSE mode, he measu e o da kening is indi ec ly p opo ional o
he a e age a omic weigh o he elemen s p esen a he gi en poin . The ligh e elemen s
a e shown as da ke — he solid solu ion Al, while he hea ie elemen s a e shown as
b igh e — he solid solu ion Zn.
The mic os uc u e o he Zn–Al–Cu solde is shown in Figu e 8. The s uc u e is,
a i s sigh , o med o he solid solu ion Zn and he solid solu ion Al. Acco ding o he
phase diag am in Figu e 8, he solde ma ix con ains also he
ε
-CuZn
4
phase (e en ually
Cu0.2Zn0.8 phase).
Fo de e mina ion o he chemical composi ion o he indi idual componen s o
he solde ing alloy, local chemical EDX mic oanalysis was pe o med. The poin s o
measu emen shown in Figu e 8a a e ma ked as Spec um 1 o Spec um 3. The p ima y
g ains (Spec um 1) in Figu e 8a a e o med o solid solu ion Zn, whe e Cu and Al a e
pa ially dissol ed. This zone is documen ed in Figu e 8d. Spec um 2 co esponds by i s
composi ion o Al phase wi h a high Zn con en , which is s able abo e he empe a u e
o 277
◦
C . Figu e 8c sugges s ha e y ine lamella eu ec ics is conce ned, wi h a highe
con en o Zn and lowe con en o Al han in he case o Spec um 3. The Spec a 3, 3a,
and 3b ep esen he eu ec ics wi h lamella s uc u e Al + Zn + a mino i y p opo ion o
ε-CuZn4 phase.
Me als 2021,11, 27 8 o 17
Figu e 8.
SEM/EDX analysis o ZnAl5Cu3 solde : (
a
,
b
) poin s o measu emen in indi idual spec a; (
c
) de ail o zone 2;
(d) de ail o zone 1.
The di ac ion XRD analysis o he Zn5Al3Cu solde has p o ed he p esence o solid
solu ion Zn, solid solu ion Al, and in e me allic phases CuZn
4
-
e
and CuAl
2
-
θ
. The CuAl
2
phase was no iden i ied by EDX analysis. The eco d om he di ac ion analysis is
documen ed in Figu e 9.
Figu e 10 shows he esul s o plana EDX analysis o his solde , whe e he solde
elemen s Zn, Al, and Cu a e di e en ia ed by colo . The g ains o solid solu ion Zn a e
clea ly isible and also he space amongs he g ains (ligh -blue colo ) illed wi h solid
solu ion Al. Coppe and i s phase CuZn4is dissipa ed mainly in he solid solu ion Zn.
Me als 2021,11, 27 9 o 17
Figu e 9. Di ac ion eco d o Zn5Al3Cu solde .
Figu e 10. Map o Zn, Al, and Cu elemen s in he s uc u e o Zn5Al3Cu solde .
3.3. Tensile S eng h o Solde ing Alloys Type Zn–Al–Cu
The mechanical es s o Zn–Al–Cu ype solde s we e pe o med. The dimensions
o he es pieces we e p oposed and calcula ed. Th ee specimens o each expe imen al
solde ing alloy we e used o ensile s eng h measu emen . The loading a e o he es
piece was 1 mm
·
min
−1
. The ensile s eng h o he Zn–Al–Cu ype solde s in dependence
on he coppe con en was de e mined. The esul s o he ensile es a e documen ed in
he g aph in Figu e 11.
Me als 2021,11, 27 16 o 17
Rega ding his iewpoin , he XDR analysis on he ac u ed su ace o he Al7075/Zn5
Al3Cu/Cu join was pe o med (Figu e 22). The p esence o Cu on he ac u ed su ace
was hus p o ed. In addi ion, obse ed we e solid solu ions o aluminum and zinc and
newly o med phases o coppe —CuZn
4
, CuAl
2
, Cu
3.2
Zn
0.7
Al
4.2
, we e also obse ed,
which a e he esul o solde in e ac ion wi h he coppe subs a e. All hese phases we e
p o ed also by EDX analysis.
Figu e 22. The XRD analysis o ac u ed su ace in Al7075/Zn5Al3Cu/Cu join .
4. Conclusions
The aim o he esea ch was o cha ac e ize he solde ing alloy o ype Zn–Al–Cu
and o s udy whe he he selec ed composi ion o he solde ing alloy is sui able o he
combina ion o coppe wi h aluminum alloy ype Al7075 wi h he applica ion o ul asonic
solde ing. The ollowing esul s we e achie ed:
•
To de e mine he mel ing poin o he solde , DSC analysis was applied. The DSC cu e
con ains wo basic peaks. The i s peak co esponds o eu ec oid ans o ma ion in he
Zn–Al sys em. The second peak co esponds o eu ec ic ans o ma ion in he same
sys em. I was ound ha he addi ion o Cu o he solde inc eases he empe a u e o
eu ec oid ans o ma ion o app oxima ely 285
◦
C and, ice e sa, he empe a u e o
eu ec ic ans o ma ion is educed o 378 ◦C .
•
The mic os uc u e o solde o ype Zn–Al–Cu is o med o a eu ec ic mix u e o solid
solu ions Zn + Al + Al“. Two coppe phases, CuZn
4
and CuAl
2
, we e iden i ied in he
solde ma ix.
•
The a e age ensile s eng h o solde ing alloys o ype Zn–Al–Cu eaches alues
om 167 o 187 MPa. I was ound ha he addi ion o coppe pa ially educes he
ensile s eng h o solde ing alloys o ype Zn–Al–Cu. The addi ion o 3 w . % Cu o
Zn5Al solde will educe he a e age ensile s eng h by 38 MPa. This is caused by he
o ma ion o coppe phases o ype CuZn4and CuAl2.
•
The bond o aluminum alloy wi h Zn5Al3Cu solde is o med due o he dissolu ion
o Al in zinc solde a he o ma ion o solid solu ion Al. The wid h o he solubili y
band wi h he solid solu ion Al was 5 o 11 µm.
•
Two new in e me allic phases, namely Al(Cu,Zn)
2
and Cu
3.2
Zn
0.7
Al
4.2
, we e iden i ied
in he bounda y o he Cu/Zn5Al3Cu join , which a e he esul o in e ac ion o he
zinc solde and coppe subs a e. Beside he in e ac ion o Zn, also a signi ican e ec
o Al on bond o ma ion wi h he coppe subs a e was p o ed.
•
The a e age shea s eng h o he Al7075/Zn5Al3Cu/Cu join had a alue o 134.5 MPa.
Fo compa ison, he Cu/Zn5Al3Cu/Cu join a ained an a e age shea s eng h o
136.5 MPa.

Me als 2021,11, 27 17 o 17
Au ho Con ibu ions:
Concep ualiza ion, R.K. and I.K.; me hodology, R.K.; alida ion, R.K., I.K.
and J.D.; o mal analysis, J.D., P.B. and M.S.; in es iga ion, R.K. and I.K.; da a cu a ion, I.K.; w i ing—
o iginal d a p epa a ion, R.K.; w i ing— e iew and edi ing, I.K.; isualiza ion, I.K.; supe ision,
R.K.; p ojec adminis a ion, I.K.; All au ho s ha e ead and ag eed o he published e sion o he
manusc ip .
Funding:
This wo k was suppo ed by he Slo ak Resea ch and De elopmen Agency unde con ac
no. APVV-17-0025 and by he scien i ic g an agency o he Minis y o Educa ion o he Slo ak
Republic and o Slo ak Academy o Sciences unde con ac no. VEGA 1/0303/20.
Acknowledgmen s:
The pape was also p epa ed in coope a ion wi h he VSB—Technical Uni e si y
o Os a a, FMT—Facul y o Ma e ials Science and Technology, Depa men o Non- e ous Me als,
Re ining and Recycling.
Con lic s o In e es : The au ho s decla e no con lic o in e es .
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