Ci a ion: Ba enyi, I.; Slany, M.;
Kou il, K.; Zouha , J.; Kolomy, S.;
Sedlak, J.; Maje ik, J. P ocessing o
Bime allic Inconel 625-16Mo3 S eel
Tube ia Supe c i ical Bend: S udy o
he Mechanical P ope ies and
S uc u e. Ma e ials 2023,16, 6796.
h ps://doi.o g/10.3390/
ma16206796
Academic Edi o : Toshio Ogawa
Recei ed: 2 Oc obe 2023
Re ised: 18 Oc obe 2023
Accep ed: 19 Oc obe 2023
Published: 21 Oc obe 2023
Copy igh : © 2023 by he au ho s.
Licensee 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/).
ma e ials
A icle
P ocessing o Bime allic Inconel 625-16Mo3 S eel Tube ia
Supe c i ical Bend: S udy o he Mechanical P ope ies
and S uc u e
Igo Ba enyi 1, Ma in Slany 2,* , Ka el Kou il 2, Jan Zouha 2, S epan Kolomy 2, Jose Sedlak 2
and Joze Maje ik 1
1Facul y o Special Technology, Alexande Dubcek Uni e si y o T encin, 911 06 T enˇcín, Slo akia;
igo [email p o ec ed] (I.B.); [email p o ec ed] (J.M.)
2Facul y o Mechanical Enginee ing, Ins i u e o Manu ac u ing Technology, B no Uni e si y o Technology,
616 69 B no, Czech Republic; ka el.kou il@ u b .cz (K.K.); [email p o ec ed].cz (J.Z.);
s epan.kolomy@ u b .cz (S.K.); [email p o ec ed].cz (J.S.)
*Co espondence: slany[email p o ec ed].cz
Abs ac :
Incine a ion is cu en ly he s anda d way o disposing o municipal was e. I uses compo-
nen s p o ec ed by high- empe a u e- esis an laye s o ma e ials, such as Inconel alloys. The e o e,
he objec i e o he cu en pape is o s udy he mechanical p ope ies and s uc u e o a bime allic
Inconel 625-16Mo3 s eel ube. The Inconel 625 laye was 3.5 mm hick and was applied o he su ace
o he ube wi h a wall hickness o 7 mm ia he cold me al ans e me hod. The bime allic ube was
ben using a supe c i ical bend (d
≤
0.7D). This pape is ocused on he in es iga ion o he ma e ial
changes in he Inconel 625 laye a eas in luenced by he maximum ensile and comp essi e s esses
a e he bend. The change in laye hickness a e he bend was e alua ed and compa ed o he
non-de o med ube. In addi ion, he local mechanical p ope ies (nanoha dness, Young modulus)
ac oss he indica ed in e acial a eas using quasis a ic nanoinden a ion we e in es iga ed. Subse-
quen ly, a ho ough mic os uc u e obse a ion was ca ied ou in a eas wi h maximum ensile and
comp essi e s esses o de e mine changes in he mo phology and size o dend i es ela ed o he
e ec o ensile o comp essi e s esses induced by bending. I was ound ha he g ain ea u ed
a s e ched seconda y dend i e axis in he a ea o ensile s ess, bu comp essi e s ess impa ed a
p olonga ion o he p ima y dend i e axis.
Keywo ds:
Inconel 625; bime allic ma e ial; welding; mechanical p ope ies; mic os uc u e; supe -
c i ical bend
1. In oduc ion
In ecen yea s, he incine a ion o municipal was e has become a a o able al e na-
i e o adi ional was e land illing. In addi ion o was e disposal, incine a ion has o he
bene i s. The gene a ed hea ene gy can be used o c ea e elec ici y o o hea ing. Despi e
i s ad an ages, he incine a ion p ocess also poses a p oblem ha mus be sol ed. The
empe a u e when incine a ing o dina y municipal was e is abou 800 o 900
◦
C, and o
haza dous was e, empe a u es up o 1300
◦
C a e used. The combus ion en i onmen is e y
agg essi e, and he componen s mus wi hs and he high- empe a u e co osion caused by
Cl, N
2
, O
2
, e c. One o he a ailable solu ions is o apply a p o ec i e Inconel 625 laye o he
componen . The componen om which he expe imen al samples we e made is pa o an
incine a ion chambe o municipal was e. I is a 16Mo3 s eel ube h ough which supe c i i-
cal cooling wa e lows, and i s ou e su ace is unde he in luence o agg essi e condi ions.
The main damage ac o is he high- empe a u e in luence (abou 500
◦
C) and subsequen
high- empe a u e co osion in a chemically agg essi e en i onmen . The e o e, he ube
is coa ed wi h an Inconel 625 laye wi h esis ance o hese condi ions [
1
,
2
]. The laye is
Ma e ials 2023,16, 6796. h ps://doi.o g/10.3390/ma16206796 h ps://www.mdpi.com/jou nal/ma e ials
Ma e ials 2023,16, 6796 2 o 15
made using he cold me al ans e (CMT) me hod. CMT welding is a modi ied MIG/MAG
welding p ocess based on a sho -ci cui ing ans e p ocess de eloped by he Aus ian
welding company F onius in 2004. This p ocess was de eloped based on he MIG/MAG
welding p ocess bu di e s in he ype o d ople ans e me hod, which had no been
p e iously encoun e ed [
3
,
4
]. The con en ional MIG/MAG p ocess uses sho -ci cui ing
d ople ans e , while CMT employs a new mechanical d ople -cu ing me hod o ans e
mol en me al o he weld [
2
]. Mo eo e , CTM uses shallow cu en s ha lead o a signi ican
educ ion in hea gene a ion. A new ype o d ople ans e educes he Fe con en in he
clad laye , leading o enhanced coa ing esis ance o high- empe a u e co osion [
5
]. The
dissolu ion o he base me al in he clad laye is almos negligible, esul ing in a e y na ow
usion zone and a na owe HAZ compa ed o he MIG/MAG p ocess [
5
]. The p inciple,
ad an ages, limi a ions, and applica ions o he CMT echnique we e discussed by Lo enzin
and Ru ili in de ail in hei wo k [
4
]. Du ing welding, empe a u e a ia ions in welds and
pa en me als ha e impo an e ec s on ma e ial cha ac e is ics and esidual s esses, as
well as on he dimensional and shape accu acies o welded p oduc s [
6
,
7
]. The CMT me hod
has been e ec i ely used o he welding and cladding o Inconel, Aluminum, Ti anium
alloys, s eels, and o he ma e ials [8–12].
The coa ed ube is ben by supe c i ical bending (d
≤
0.7D; d is he diame e o he
bend; D is he diame e o he ube) as pa o he manu ac u ing p ocess o he incine a o
componen [
13
,
14
]. The pa ame e s and mechanical p ope ies o he bend we e analyzed,
and a speci ic p ocedu e was de eloped o cold-bend he ube wi h he use o sand illing
inside o bend i wi hou c acking and excessi e de o ma ion o i s c oss-sec ion [13,14].
Cold bending equi es a e y high alue o he yield s eng h o he ma e ial o cause
a shape change in he ma e ial, which leads o he plas ic de o ma ion o he ma e ial.
The ensile s eng h canno be exceeded o a oid ma e ial ailu e. In e nal s esses a ise
in he ma e ial due o cold bending. The ac ing s esses and de o ma ions du ing ube
cold bending (see Figu e 1) we e analyzed by se e al au ho s using ma e ials including
he clad laye o Inconel 625 [
15
–
18
]. Du ing each bending p ocess, ensile s esses (
σ
)
occu in he ou e laye s o he wo kpiece ela i e o he bending adius, and elonga ion
o he ma e ial occu s in his a ea (
ε
). On he con a y, he inne laye s a e subjec ed o
comp essi e s esses (
σc
), and he ma e ial is comp essed (
εc
) in his a ea. Among hem is
he so-called non-de o med laye wi hou ac ing longi udinal s esses, whe e
ε
= 0 (neu al
axis), and hus, he ma e ial e ains i s o iginal shape and olume. This laye does no
copy he heo e ical bend adius bu is shi ed inwa d in he di ec ion o he bend axis. Fo
his eason, ce ain elonga ion occu s du ing he bending p ocess o he ube, which can
be de e mined by using a ma hema ical calcula ion. When bending a hollow ube wi h
a cons an wall hickness, he men ioned s esses ha e an analogous e ec on he wall
hickness. The e is a dec ease in he ou e adius ela i e o he heo e ical bending adius,
and on he con a y, in he inne adius, he hickness o he wall inc eases.
Ma e ials 2023, 16, x FOR PEER REVIEW 2 o 15
condi ions [1,2]. The laye is made using he cold me al ans e (CMT) me hod. CMT
welding is a modi ied MIG/MAG welding p ocess based on a sho -ci cui ing ans e
p ocess de eloped by he Aus ian welding company F onius in 2004. This p ocess was
de eloped based on he MIG/MAG welding p ocess bu diffe s in he ype o d ople
ans e me hod, which had no been p e iously encoun e ed [3,4]. The con en ional
MIG/MAG p ocess uses sho -ci cui ing d ople ans e , while CMT employs a new me-
chanical d ople -cu ing me hod o ans e mol en me al o he weld [2]. Mo eo e , CTM
uses shallow cu en s ha lead o a signi ican educ ion in hea gene a ion. A new ype
o d ople ans e educes he Fe con en in he clad laye , leading o enhanced coa ing
esis ance o high- empe a u e co osion [5]. The dissolu ion o he base me al in he clad
laye is almos negligible, esul ing in a e y na ow usion zone and a na owe HAZ
compa ed o he MIG/MAG p ocess [5]. The p inciple, ad an ages, limi a ions, and appli-
ca ions o he CMT echnique we e discussed by Lo enzin and Ru ili in de ail in hei wo k
[4]. Du ing welding, empe a u e a ia ions in welds and pa en me als ha e impo an
effec s on ma e ial cha ac e is ics and esidual s esses, as well as on he dimensional and
shape accu acies o welded p oduc s [6,7]. The CMT me hod has been effec i ely used o
he welding and cladding o Inconel, Aluminum, Ti anium alloys, s eels, and o he ma e-
ials [8–12].
The coa ed ube is ben by supe c i ical bending (d ≤ 0.7D; d is he diame e o he
bend; D is he diame e o he ube) as pa o he manu ac u ing p ocess o he incine a o
componen [13,14]. The pa ame e s and mechanical p ope ies o he bend we e analyzed,
and a speci ic p ocedu e was de eloped o cold-bend he ube wi h he use o sand illing
inside o bend i wi hou c acking and excessi e de o ma ion o i s c oss-sec ion [13,14].
Cold bending equi es a e y high alue o he yield s eng h o he ma e ial o cause
a shape change in he ma e ial, which leads o he plas ic de o ma ion o he ma e ial. The
ensile s eng h canno be exceeded o a oid ma e ial ailu e. In e nal s esses a ise in he
ma e ial due o cold bending. The ac ing s esses and de o ma ions du ing ube cold bend-
ing (see Figu e 1) we e analyzed by se e al au ho s using ma e ials including he clad
laye o Inconel 625 [15–18]. Du ing each bending p ocess, ensile s esses (σ ) occu in he
ou e laye s o he wo kpiece ela i e o he bending adius, and elonga ion o he ma e ial
occu s in his a ea (ε ). On he con a y, he inne laye s a e subjec ed o comp essi e
s esses (σc), and he ma e ial is comp essed (εc) in his a ea. Among hem is he so-called
non-de o med laye wi hou ac ing longi udinal s esses, whe e ε = 0 (neu al axis), and
hus, he ma e ial e ains i s o iginal shape and olume. This laye does no copy he he-
o e ical bend adius bu is shi ed inwa d in he di ec ion o he bend axis. Fo his eason,
ce ain elonga ion occu s du ing he bending p ocess o he ube, which can be de e -
mined by using a ma hema ical calcula ion. When bending a hollow ube wi h a cons an
wall hickness, he men ioned s esses ha e an analogous effec on he wall hickness.
The e is a dec ease in he ou e adius ela i e o he heo e ical bending adius, and on
he con a y, in he inne adius, he hickness o he wall inc eases.
Figu e 1. Ac ing s esses and de o ma ions du ing he bending p ocess.
The au ho s Guo, X. e al. [19] ca ied ou simula ions and eal expe imen s on H62
b ass ube bends wi h diffe en pa ame e s and in es iga ed he in luence o hese
σ
+σ
-σ
ε
+ε
-ε
ε
c
σ
c
neu al axis
Figu e 1. Ac ing s esses and de o ma ions du ing he bending p ocess.
The au ho s Guo, X. e al. [
19
] ca ied ou simula ions and eal expe imen s on H62
b ass ube bends wi h di e en pa ame e s and in es iga ed he in luence o hese pa am-
e e s on he bending p ope ies. As pa o hei expe imen s, hey also in es iga ed he
Ma e ials 2023,16, 6796 3 o 15
dependence o he bending a io, R/D
0
(R—bending adius; D— ube diame e ), on he
esul ing s esses and he a io o he pipe wall hickness be o e and a e bending. Thei
expe imen s p o ed ha wi h he inc ease in he bending a io, he alue o in e nal s esses
caused by bending dec eased exponen ially. Also, he wall hickness a io be ween he
o iginal ube and he ben ube dec eased wi h he inc easing bending a io R/D
0
[
19
]. The
au ho s e alua ed he men ioned pa ame e s a he place o maximum comp essi e s esses
in he lowe pa o he bending a c.
Du ing he cold bending o he ube, plas ic de o ma ion o he ma e ial occu s, which
causes s ain ha dening. This is a undamen al ac o in assessing ha dness changes in
he a eas o he ma e ial mos a ec ed by bending s esses. The au ho s Ka suji Tosha
e al. [
20
] di ec ly e alua ed he e ec o comp essi e and ensile s esses on he inal
ha dness o ben shee s in a su ace laye a e he shee bending o C45 s eel. Thei esul s
show ha ha dness alues a e bending dec ease wi h inc easing ensile s esses bu
inc ease wi h inc easing comp essi e s esses. Howe e , wo k ha dening in bo h a eas
wi h ensile s ess and comp essi e s ess has a no iceable in luence. In he a eas whe e he
ensile s ain is o e 1%, he alue o he ha dness inc emen wi h wo k ha dening is la ge
han he ha dness dec emen caused by he ensile s esses hemsel es [
20
]. The ha dness
inc eases wi h he comp essi e s ess in he elas ic s ain s age and inc eases apidly a e
he comp essi e s ess eaches he plas ic s ain s age due o wo k ha dening. In gene al,
in egions o bends wi h plas ic de o ma ion and subsequen wo k ha dening, whe he
by ensile o comp essi e s esses, ha dness alues inc ease. The highes ha dness alues
we e measu ed in he a ea o he highes comp essi e s esses, whe e he e ec o s ain
ha dening is combined wi h he ac ion o comp essi e s esses [20].
Se e al au ho s ha e used nanoinden a ion o e alua e he nanomechanical beha io
and local mechanical p ope ies o laye s and coa ings [
21
–
24
]. Quasis a ic nanoinden a ion
es s in ol e pushing a diamond- ipped inden e head in o a ma e ial unde ei he load
o displacemen con ol. The inden a ion esponse o he subsu ace laye s o he ma e ial
can be in luenced by a change in i s plas ic beha io caused by in e nal s esses [
25
].
Resea che s [
25
,
26
] no ed he in luence o in e nal s esses on he pe manen plas ic dep h
de e mined a e inden a ion and he con ac su ace. This in luence is smalle when using
sha p inden a ion ips, such as hose wi h Be ko ich- ype geome y. Also, me hods we e
de eloped o measu e and e alua e in e nal s esses using nanoinden a ion [
25
] based on
di e ences in con ac a ea measu emen s. These small di e ences should co espond o
in e nal s esses.
P e ious wo ks by he au ho s’ collec i e [
13
,
14
] we e ocused on he s udy o he
abili y o c ea e c i ical and supe c i ical bends in bime al pipes (i.e., bends smalle han
1D, speci ically 0.7D) wi h Inconel 625 cladding, and his solu ion has no been published
in any o he s udy so a . While hese p e ious s udies mainly deal wi h he echnological
pa ame e s o he bending p ocess in ela ion o he p esence o possible de ec s, his wo k
is ocused on he de ailed ma e ial in es iga ion o he mic os uc u e and nanomechanical
p ope ies (nanoha dness, educed modulus) o an Inconel 625 cladding laye in di e en
a eas a ec ed by s esses caused by he bending p ocess. The main goal is o ob ain a
comp ehensi e o e iew o he beha io o he laye ma e ial du ing bending wi h he
possibili y o u he in es iga ing he damage mechanism o he laye by high- empe a u e
and chemically agg essi e condi ions.
2. Ma e ials and Me hods
2.1. Expe imen al Ma e ials
As men ioned abo e, a ben 16Mo3 s eel ube wi h an Inconel 625 weld o e lay
was used o expe imen s. The subs a e, 16Mo3 middle-alloyed s eel, is hea - esis an
s eel o use a highe empe a u es and p essu es. I has good o mabili y, weldabili y,
and co osion esis ance in a wa e apo en i onmen up o 530
◦
C. I is supplied in
a s a e a e annealing, whe e he esul ing s uc u e is e i e and pea li e (Figu e 2a).
Ma e ials 2023,16, 6796 4 o 15
The mic os uc u e was obse ed in he cen e a ea o he ube wall. The basic chemical
composi ion and mechanical p ope ies o 16Mo3 s eel a e shown in Table 1.
Ma e ials 2023, 16, x FOR PEER REVIEW 4 o 15
annealing, whe e he esul ing s uc u e is e i e and pea li e (Figu e 2a). The mic os uc-
u e was obse ed in he cen e a ea o he ube wall. The basic chemical composi ion and
mechanical p ope ies o 16Mo3 s eel a e shown in Table 1.
Table 1. Chemical composi ion and mechanical p ope ies o 16Mo3 s eel.
w .% C Mn Si Mo Al P S Fe
16Mo3
s eel
min. 0.1 0.5 0.15 0.25 -- -- -- Balance
max. 0.20 0.8 0.37 0.35 0.015 0.04 0.04
Tensile s eng h
R
m
(MPa)
Yield poin
R
p0,2
(MPa)
Duc ili y
A (%) Ha dness HB
440 380 30 150
(a) (b)
Figu e 2. (a) SEM mic os uc u e image o 16Mo3 s eel (subs a e)— he cen e o he ube wall; (b)
SEM mic os uc u e image o Inconel 625 clad laye (wi hou bend).
Inconel 625 is a hea - esis an and c eep- esis an nickel alloy (NiC 22Mo9Nb). The
chemical composi ion and mechanical p ope ies o Inconel 625 a e lis ed in Table 2. The
alloy is subs i u ionally s eng hened by Ni, bu Nb and o he p esen elemen s can cause
addi ional p ecipi a ion s eng hening. The basic mic os uc u e o Inconel 625 cladding
is homogeneous, con aining only g ains o γ solid solu ion (Figu e 2b) in he o m o den-
d i es. The e a e also some seconda y phases—p ecipi a es o γ’ and γ’’ on he g ain
bounda ies [27]. The Nb p ecipi a es in he γ” phase, while Ti and Al o m he γ’ phase.
The γ” phase con ibu es mo e o he ha dening effec han he γ’ phase [28]. The mic o-
s uc u e and mechanical p ope ies o Inconel 625 supe alloy a e desc ibed in mo e de ail
by o he au ho s [29,30].
Inconel 625 wi e, 1 mm in diame e , was used o o e weld he laye on he subs a e
using he CMT me hod. The diame e o he basic ube was D = Ø38 mm, while i s wall
hickness was 7 mm. Addi ionally, he o e welded ou e laye o Inconel 625 had an a -
e age hickness o 3.5 mm.
Table 2. Chemical composi ion and mechanical p ope ies o Inconel 625.
w .% C Mo Co Nb Ti Fe C Mn Si Al P S Ni
Inconel 625
(NiC 22Mo9Nb)
min. 20 8 -- 3.15 -- -- -- -- -- -- -- -- Balance
max. 23 10 1 4.15 0.4 5 0.1 0.5 0.5 0.4 0.015 0.015
Tensile s eng h
R
m
(MPa)
Yield poin
R
p0,2
(MPa)
Duc ili y
A (%)
Ha dness
HV
965 490 50 200
2.2. Expe imen al Sample P epa a ion
The ube was ben using a supe c i ical bend, whe e d ≤ 0.7D (d is he diame e o he
bend; D is he diame e o he ube) a ambien empe a u e wi h an applied bending
Figu e 2.
(
a
) SEM mic os uc u e image o 16Mo3 s eel (subs a e)— he cen e o he ube wall;
(b) SEM mic os uc u e image o Inconel 625 clad laye (wi hou bend).
Table 1. Chemical composi ion and mechanical p ope ies o 16Mo3 s eel.
w .% C Mn Si Mo Al P S Fe
16Mo3
s eel
min. 0.1 0.5 0.15 0.25 -- -- -- Balance
max. 0.20 0.8 0.37 0.35 0.015 0.04 0.04
Tensile s eng h
Rm(MPa)
Yield poin
Rp0,2 (MPa)
Duc ili y
A (%)
Ha dness
HB
440 380 30 150
Inconel 625 is a hea - esis an and c eep- esis an nickel alloy (NiC 22Mo9Nb). The
chemical composi ion and mechanical p ope ies o Inconel 625 a e lis ed in Table 2. The
alloy is subs i u ionally s eng hened by Ni, bu Nb and o he p esen elemen s can cause
addi ional p ecipi a ion s eng hening. The basic mic os uc u e o Inconel 625 cladding
is homogeneous, con aining only g ains o
γ
solid solu ion (Figu e 2b) in he o m o
dend i es. The e a e also some seconda y phases—p ecipi a es o
γ
’ and
γ
” on he g ain
bounda ies [
27
]. The Nb p ecipi a es in he
γ
” phase, while Ti and Al o m he
γ
’ phase. The
γ
” phase con ibu es mo e o he ha dening e ec han he
γ
’ phase [
28
]. The mic os uc u e
and mechanical p ope ies o Inconel 625 supe alloy a e desc ibed in mo e de ail by o he
au ho s [29,30].
Table 2. Chemical composi ion and mechanical p ope ies o Inconel 625.
W .% C Mo Co Nb Ti Fe C Mn Si Al P S Ni
Inconel 625
(NiC 22Mo9Nb)
min. 20 8 -- 3.15 -- -- -- -- -- -- -- -- Balance
max. 23 10 1 4.15 0.4 5 0.1 0.5 0.5 0.4 0.015 0.015
Tensile s eng h
Rm(Mpa)
Yield poin
Rp0,2 (Mpa)
Duc ili y
A (%)
Ha dness
HV
965 490 50 200
Inconel 625 wi e, 1 mm in diame e , was used o o e weld he laye on he subs a e
using he CMT me hod. The diame e o he basic ube was D = Ø38 mm, while i s wall
hickness was 7 mm. Addi ionally, he o e welded ou e laye o Inconel 625 had an
a e age hickness o 3.5 mm.
Ma e ials 2023,16, 6796 5 o 15
2.2. Expe imen al Sample P epa a ion
The ube was ben using a supe c i ical bend, whe e d
≤
0.7D (d is he diame e o
he bend; D is he diame e o he ube) a ambien empe a u e wi h an applied bending
momen o 25.5 kNm. The c oss-sec ion o he ben ube pa used o he p epa a ion o
he expe imen al sample is shown in Figu e 3. The samples we e aken om wo a eas
wi h he g ea es in e nal ensile and comp essi e s esses a e bending (see Figu e 1). The
place wi h maximum ensile s esses, ma ked as OR (ou e adius), is loca ed a he op
o he bending a c. The place wi h maximum comp essi e s esses, ma ked as IR (inne
adius), is loca ed a he bo om o he bending a c.
Ma e ials 2023, 16, x FOR PEER REVIEW 5 o 15
momen o 25.5 kNm. The c oss-sec ion o he ben ube pa used o he p epa a ion o
he expe imen al sample is shown in Figu e 3. The samples we e aken om wo a eas
wi h he g ea es in e nal ensile and comp essi e s esses a e bending (see Figu e 1).
The place wi h maximum ensile s esses, ma ked as OR (ou e adius), is loca ed a he
op o he bending a c. The place wi h maximum comp essi e s esses, ma ked as IR (in-
ne adius), is loca ed a he bo om o he bending a c.
The samples p epa ed om he ma ked places we e hen p ocessed by using a s and-
a d me allog aphic sample p epa a ion p ocedu e, including p essing in o a bakeli e mix-
u e, g inding, polishing, and e ching. Glyce egia (50% HCl, 33% glyce ol, and 17%
HNO3) was used as an e chan o he Inconel 625 laye mic os uc u e. The inal samples
we e used bo h o nanoinden a ion measu emen and o ligh mic oscopic s uc u al
obse a ions. Ligh mic oscopic analysis, including some quan i a i e mic oscopy pa am-
e e s (dend i e dimensions), was pe o med using a con ocal lase measu emen mic o-
scope Olympus Lex OLD5100, Olympus IMS, Webs e (Olympus, T encin, Slo akia) and
i s analy ical so wa e—S eam e sion 2.4. The s uc u es in luenced by ensile and com-
p essi e s esses we e obse ed ia he ULTRA PLUS scanning elec on mic oscope (Ca l
Zeiss, Homb ech ikon, Swi ze land). EBSD analysis was pe o med ia EBSD NORDLYS
(Ox o d Ins umen s, Abingdon, England), and NANO Binning was se o 4 × 4. The meas-
u ing EHT ol age was se o 20 kV wi h a spo size o 120 µm, and he cu en was 3 nA.
The scanning a ea o he samples was, in all cases, 1 × 0.75 mm.
Figu e 3. C oss-sec ion o he ube pa used o expe imen al sample p epa a ion.
2.3. Quasis a ic Nanoinden a ion
Quasis a ic nanoinden a ion is used o measu e he cou ses o nanoha dness and he
educed Young modulus ac oss Inconel laye s om he su ace o a ce ain dep h. The
me hod was i s in oduced by Oli e and Pha [31] and is based on pushing a diamond-
ipped inden e head in o a ma e ial, whe e he displacemen (h) as a unc ion o he load
(F) is moni o ed du ing bo h he loading and unloading cycles o he inden a ion p ocess.
The esul ing ela ion F-h is called he nanoinden a ion cu e (Figu e 4a). The loading pa
o he cu e is used o e alua e nanoha dness H, which is de ined as he con ac p essu e
unde he inden e [32]:
𝐻=𝐹
𝐴
 (1)
whe e F is he load, and Ac is he p ojec ed con ac a ea calcula ed a a dep h o inden a ion
h. The unloading pa is ela ed o eco e ing elas ic de o ma ion and can be used o cal-
cula e he Young modulus o he ma e ial.
The ini ial slope (S) o he unloading cu e can be ela ed o he elas ic modulus o
he ma e ial using he equa ion [32]:
𝑆=𝑑𝐹
𝑑ℎ =2𝐸

𝐴

√
𝜋 (2)
whe e S is he ini ial slope o he unloading cu e o con ac s iffness, F is he applied load,
and E is he educed Young modulus.
Figu e 3. C oss-sec ion o he ube pa used o expe imen al sample p epa a ion.
The samples p epa ed om he ma ked places we e hen p ocessed by using a s anda d
me allog aphic sample p epa a ion p ocedu e, including p essing in o a bakeli e mix u e,
g inding, polishing, and e ching. Glyce egia (50% HCl, 33% glyce ol, and 17% HNO
3
) was
used as an e chan o he Inconel 625 laye mic os uc u e. The inal samples we e used
bo h o nanoinden a ion measu emen and o ligh mic oscopic s uc u al obse a ions.
Ligh mic oscopic analysis, including some quan i a i e mic oscopy pa ame e s (dend i e
dimensions), was pe o med using a con ocal lase measu emen mic oscope Olympus Lex
OLD5100, Olympus IMS, Webs e (Olympus, T encin, Slo akia) and i s analy ical so wa e—
S eam e sion 2.4. The s uc u es in luenced by ensile and comp essi e s esses we e
obse ed ia he ULTRA PLUS scanning elec on mic oscope (Ca l Zeiss, Homb ech ikon,
Swi ze land). EBSD analysis was pe o med ia EBSD NORDLYS (Ox o d Ins umen s,
Abingdon, England), and NANO Binning was se o 4
×
4. The measu ing EHT ol age
was se o 20 kV wi h a spo size o 120
µ
m, and he cu en was 3 nA. The scanning a ea o
he samples was, in all cases, 1 ×0.75 mm.
2.3. Quasis a ic Nanoinden a ion
Quasis a ic nanoinden a ion is used o measu e he cou ses o nanoha dness and he
educed Young modulus ac oss Inconel laye s om he su ace o a ce ain dep h. The
me hod was i s in oduced by Oli e and Pha [
31
] and is based on pushing a diamond-
ipped inden e head in o a ma e ial, whe e he displacemen (h) as a unc ion o he load
(F) is moni o ed du ing bo h he loading and unloading cycles o he inden a ion p ocess.
The esul ing ela ion F-h is called he nanoinden a ion cu e (Figu e 4a). The loading pa
o he cu e is used o e alua e nanoha dness H, which is de ined as he con ac p essu e
unde he inden e [32]:
H=F
Ac(1)
whe e Fis he load, and A
c
is he p ojec ed con ac a ea calcula ed a a dep h o inden a ion
h. The unloading pa is ela ed o eco e ing elas ic de o ma ion and can be used o
calcula e he Young modulus o he ma e ial.

Ma e ials 2023,16, 6796 6 o 15
Ma e ials 2023, 16, x FOR PEER REVIEW 6 o 15
(a) (b)
Figu e 4. (a) Nanoinden a ion cu e o eal ma e ial and (b) loading cu e used o he expe imen .
The con en ional Young modulus o he sample (E
s
) can be ela ed o he educed
modulus (E
) using Equa ion (3), p o ided ha he inden e modulus (E
i
) and Poisson’s
a ios o he specimen and inden e (ν
s
and ν
i
, espec i ely) a e known o can be es ima ed
[32]:
1
𝐸=1𝜈


𝐸1𝜈


𝐸 (3)
Quasis a ic nanoinden a ion measu emen s we e pe o med wi h a Hysi on T i-
boinden e TI950 (Ma e ials Resea ch Labo a o y, U bana, IL, USA), whe e he expe i-
men al esul s we e analyzed using i s so wa e, Hysi on T iboscan e sion 1.0. A s and-
a d apezoid wi h maximum o ce F = 10,000 µN and holding ime = 2 s was chosen as
he loading cu e o e e y ealized inden a ion poin , as is shown in Figu e 4b. A Be ko-
ich inden a ion ip was used o he expe imen , which has sufficien sha pness o he
used expe imen al ma e ials. The numbe o nanoinden a ion poin s was chosen speci i-
cally o each Inconel laye a ea ype sepa a ely in a way o co e he en i e hickness o
he laye in he a ea. The s ep (dis ance) be ween poin s was cons an —150 µm.
3. Resul s
3.1. Change in Laye Dep h a e Bending
The change in he hickness o he welded laye due o bending was analyzed as pa
o he expe imen s, oo. The measu emen was ca ied ou wi h a ligh mic oscope and i s
e alua ion so wa e on mac os uc u e pho og aphs. The achie ed esul s a e shown in
Figu e 5a. Figu e 5b shows he esul s in pola coo dina es, including changes in he o al
wall hickness o he ube. The pola coo dina e iew displays he comple e scheme o he
bending a c and allows he isualiza ion o he ube wall de o ma ion, including Inconel
laye s on bo h sides o he ube. The eg ession equa ions modeled on he basis o expe i-
men al da a o hicknesses (Figu e 5a) clea ly indica e he maximum o minimum hick-
ness a he op o he bend, whe e α = 90°.
As a esul o bending, he welded Inconel laye on he ou e a c o he bend became
hinne due o he ensile s esses p esen . The maximum hinning is a he op o he ou e
a c (α = 90°, 73% o he o iginal hickness o he laye ). A sample labeled OR was aken
om his a ea. In con as , he hickening o he Inconel laye occu ed due o he p esence
o comp essi e s esses in he lowe bend a c. The Inconel laye on his side o he a c o
he bend has he maximum hickness (α = 90°, 149% o he hickness o he o iginal laye ).
A sample labeled IR was aken om his a ea o he bending a c.
The laye hickness changes a e bending a e ela ed o he ypes o in e nal s esses
and hei dis ibu ion wi hin he Inconel 625 laye .
h
p
h
e
h
max
h
F
max
F
dF
dh
Loading
Unloadin
g
Figu e 4. (a) Nanoinden a ion cu e o eal ma e ial and (b) loading cu e used o he expe imen .
The ini ial slope (S) o he unloading cu e can be ela ed o he elas ic modulus o he
ma e ial using he equa ion [32]:
S=dF
dh =2E √Ac
√π(2)
whe e Sis he ini ial slope o he unloading cu e o con ac s i ness, Fis he applied load,
and E is he educed Young modulus.
The con en ional Young modulus o he sample (E
s
) can be ela ed o he educed mod-
ulus (E ) using Equa ion (3), p o ided ha he inden e modulus (Ei) and Poisson’s a ios
o he specimen and inden e (νsand νi, espec i ely) a e known o can be es ima ed [32]:
1
E
=1−ν2
s
ES
+1−ν2
i
Ei
(3)
Quasis a ic nanoinden a ion measu emen s we e pe o med wi h a Hysi on T iboin-
den e TI950 (Ma e ials Resea ch Labo a o y, U bana, IL, USA), whe e he expe imen al
esul s we e analyzed using i s so wa e, Hysi on T iboscan e sion 1.0. A s anda d
apezoid wi h maximum o ce F = 10,000
µ
N and holding ime = 2 s was chosen as he
loading cu e o e e y ealized inden a ion poin , as is shown in Figu e 4b. A Be ko ich
inden a ion ip was used o he expe imen , which has su icien sha pness o he used
expe imen al ma e ials. The numbe o nanoinden a ion poin s was chosen speci ically o
each Inconel laye a ea ype sepa a ely in a way o co e he en i e hickness o he laye in
he a ea. The s ep (dis ance) be ween poin s was cons an —150 µm.
3. Resul s
3.1. Change in Laye Dep h a e Bending
The change in he hickness o he welded laye due o bending was analyzed as pa
o he expe imen s, oo. The measu emen was ca ied ou wi h a ligh mic oscope and
i s e alua ion so wa e on mac os uc u e pho og aphs. The achie ed esul s a e shown
in Figu e 5a. Figu e 5b shows he esul s in pola coo dina es, including changes in he
o al wall hickness o he ube. The pola coo dina e iew displays he comple e scheme
o he bending a c and allows he isualiza ion o he ube wall de o ma ion, including
Inconel laye s on bo h sides o he ube. The eg ession equa ions modeled on he basis o
expe imen al da a o hicknesses (Figu e 5a) clea ly indica e he maximum o minimum
hickness a he op o he bend, whe e α= 90◦.
As a esul o bending, he welded Inconel laye on he ou e a c o he bend became
hinne due o he ensile s esses p esen . The maximum hinning is a he op o he ou e
a c (
α
= 90
◦
, 73% o he o iginal hickness o he laye ). A sample labeled OR was aken
om his a ea. In con as , he hickening o he Inconel laye occu ed due o he p esence
o comp essi e s esses in he lowe bend a c. The Inconel laye on his side o he a c o
Ma e ials 2023,16, 6796 7 o 15
he bend has he maximum hickness (
α
= 90
◦
, 149% o he hickness o he o iginal laye ).
A sample labeled IR was aken om his a ea o he bending a c.
The laye hickness changes a e bending a e ela ed o he ypes o in e nal s esses
and hei dis ibu ion wi hin he Inconel 625 laye .
Ma e ials 2023, 16, x FOR PEER REVIEW 7 o 15
(a) (b)
Figu e 5. Inconel laye hickness depends on he posi ion angle in he bending a c (a), (b) he de-
pendence displayed in pola coo dina es, including o al wall hickness changes.
3.2. Mechanical P ope ies ac oss Inconel 625 Laye s
The cou ses o he local nanoha dness H and educed Young modulus E
we e meas-
u ed ac oss he Inconel 625 laye o he ube wi hou a bend (NB) and he ube wi h he
bend in a eas o maximum ensile s esses (OR) and maximum comp essi e s esses (IR).
I can be assumed ha ha dness alues will be in luenced by in e nal s esses h ough
inden a ion dep h measu emen s du ing he nanoinden a ion p ocess. The measu emen s
do no include he in e ace be ween he laye and he subs a e o he s ep change in he
local mechanical p ope ies wi h he alues o he subs a e. The measu emen s o he ube
wi hou he bend a e shown in Figu e 6. Bo h nanoha dness and he educed Young mod-
ulus a e cons an in he en i e measu ed laye c oss-sec ion. This was also p o en by a
eg ession analysis o he da a. The laye is homogeneous wi hou changes in H o E
.
Figu e 6. Nanoha dness and educed Young modulus cou ses ac oss he Inconel 625 laye on he
ube wi hou bend (NB).
The ben ube was analyzed by nanoinden a ion in wo a eas (see Figu e 3). The i s
a ea is a he op o he bending a c (OR), whe e he Inconel 625 laye hickness is mini-
mum, which means maximum ensile s esses. The second a ea is a he bo om o he
bending a c (IR), whe e he Inconel laye hickness is maximum due o maximum com-
p essi e s esses.
Figu e 5.
Inconel laye hickness depends on he posi ion angle in he bending a c (
a
), (
b
) he
dependence displayed in pola coo dina es, including o al wall hickness changes.
3.2. Mechanical P ope ies ac oss Inconel 625 Laye s
The cou ses o he local nanoha dness H and educed Young modulus E
we e mea-
su ed ac oss he Inconel 625 laye o he ube wi hou a bend (NB) and he ube wi h he
bend in a eas o maximum ensile s esses (OR) and maximum comp essi e s esses (IR).
I can be assumed ha ha dness alues will be in luenced by in e nal s esses h ough
inden a ion dep h measu emen s du ing he nanoinden a ion p ocess. The measu emen s
do no include he in e ace be ween he laye and he subs a e o he s ep change in he
local mechanical p ope ies wi h he alues o he subs a e. The measu emen s o he
ube wi hou he bend a e shown in Figu e 6. Bo h nanoha dness and he educed Young
modulus a e cons an in he en i e measu ed laye c oss-sec ion. This was also p o en by a
eg ession analysis o he da a. The laye is homogeneous wi hou changes in H o E .
Ma e ials 2023, 16, x FOR PEER REVIEW 7 o 15
(a) (b)
Figu e 5. Inconel laye hickness depends on he posi ion angle in he bending a c (a), (b) he de-
pendence displayed in pola coo dina es, including o al wall hickness changes.
3.2. Mechanical P ope ies ac oss Inconel 625 Laye s
The cou ses o he local nanoha dness H and educed Young modulus E
we e meas-
u ed ac oss he Inconel 625 laye o he ube wi hou a bend (NB) and he ube wi h he
bend in a eas o maximum ensile s esses (OR) and maximum comp essi e s esses (IR).
I can be assumed ha ha dness alues will be in luenced by in e nal s esses h ough
inden a ion dep h measu emen s du ing he nanoinden a ion p ocess. The measu emen s
do no include he in e ace be ween he laye and he subs a e o he s ep change in he
local mechanical p ope ies wi h he alues o he subs a e. The measu emen s o he ube
wi hou he bend a e shown in Figu e 6. Bo h nanoha dness and he educed Young mod-
ulus a e cons an in he en i e measu ed laye c oss-sec ion. This was also p o en by a
eg ession analysis o he da a. The laye is homogeneous wi hou changes in H o E
.
Figu e 6. Nanoha dness and educed Young modulus cou ses ac oss he Inconel 625 laye on he
ube wi hou bend (NB).
The ben ube was analyzed by nanoinden a ion in wo a eas (see Figu e 3). The i s
a ea is a he op o he bending a c (OR), whe e he Inconel 625 laye hickness is mini-
mum, which means maximum ensile s esses. The second a ea is a he bo om o he
bending a c (IR), whe e he Inconel laye hickness is maximum due o maximum com-
p essi e s esses.
Figu e 6.
Nanoha dness and educed Young modulus cou ses ac oss he Inconel 625 laye on he
ube wi hou bend (NB).
The ben ube was analyzed by nanoinden a ion in wo a eas (see Figu e 3). The i s
a ea is a he op o he bending a c (OR), whe e he Inconel 625 laye hickness is minimum,
Ma e ials 2023,16, 6796 8 o 15
which means maximum ensile s esses. The second a ea is a he bo om o he bending a c
(IR), whe e he Inconel laye hickness is maximum due o maximum comp essi e s esses.
Figu e 7shows he cou se o nanoha dness and he educed Young modulus ac oss
he a ea OR. The educed modulus is also cons an in his case. This indica es he absence
o any phase ans o ma ion o he o ma ion o a new phase ac oss he laye . Howe e ,
he nanoha dness H dec eases om he su ace. I s alues close o he su ace a e bigge
and g adually dec ease wi h dep h o he alues measu ed on he ube wi hou he bend.
Ma e ials 2023, 16, x FOR PEER REVIEW 8 o 15
Figu e 7 shows he cou se o nanoha dness and he educed Young modulus ac oss
he a ea OR. The educed modulus is also cons an in his case. This indica es he absence
o any phase ans o ma ion o he o ma ion o a new phase ac oss he laye . Howe e ,
he nanoha dness H dec eases om he su ace. I s alues close o he su ace a e bigge
and g adually dec ease wi h dep h o he alues measu ed on he ube wi hou he bend.
Figu e 7. Nanoha dness and educed Young modulus cou ses ac oss he Inconel 625 laye on he
ben ube— he a ea wi h maximum ensile s esses (OR).
Figu e 8 shows he cou se o nanoha dness and he educed Young modulus ac oss
he IR a ea. The educed modulus is again cons an . The nanoha dness H inc eases om
he su ace o he deepe a eas. I s alues g adually inc ease om he su ace and almos
double in alue compa ed o he nanoha dness o he ube wi hou he bend.
Figu e 8. Nanoha dness and educed Young modulus cou ses ac oss he Inconel 625 laye on he
ben ube— he a ea wi h maximum comp ess s esses (IR).
3.3. Analysis o Clad Laye Mic os uc u e a e Bending
The mic os uc u e o Inconel 625 laye s affec ed by he bending p ocess is docu-
men ed in Figu e 9, which was gene a ed using a con ocal mic oscope (Olympus Lex
Figu e 7.
Nanoha dness and educed Young modulus cou ses ac oss he Inconel 625 laye on he
ben ube— he a ea wi h maximum ensile s esses (OR).
Figu e 8shows he cou se o nanoha dness and he educed Young modulus ac oss
he IR a ea. The educed modulus is again cons an . The nanoha dness H inc eases om
he su ace o he deepe a eas. I s alues g adually inc ease om he su ace and almos
double in alue compa ed o he nanoha dness o he ube wi hou he bend.
Ma e ials 2023, 16, x FOR PEER REVIEW 8 o 15
Figu e 7 shows he cou se o nanoha dness and he educed Young modulus ac oss
he a ea OR. The educed modulus is also cons an in his case. This indica es he absence
o any phase ans o ma ion o he o ma ion o a new phase ac oss he laye . Howe e ,
he nanoha dness H dec eases om he su ace. I s alues close o he su ace a e bigge
and g adually dec ease wi h dep h o he alues measu ed on he ube wi hou he bend.
Figu e 7. Nanoha dness and educed Young modulus cou ses ac oss he Inconel 625 laye on he
ben ube— he a ea wi h maximum ensile s esses (OR).
Figu e 8 shows he cou se o nanoha dness and he educed Young modulus ac oss
he IR a ea. The educed modulus is again cons an . The nanoha dness H inc eases om
he su ace o he deepe a eas. I s alues g adually inc ease om he su ace and almos
double in alue compa ed o he nanoha dness o he ube wi hou he bend.
Figu e 8. Nanoha dness and educed Young modulus cou ses ac oss he Inconel 625 laye on he
ben ube— he a ea wi h maximum comp ess s esses (IR).
3.3. Analysis o Clad Laye Mic os uc u e a e Bending
The mic os uc u e o Inconel 625 laye s affec ed by he bending p ocess is docu-
men ed in Figu e 9, which was gene a ed using a con ocal mic oscope (Olympus Lex
Figu e 8.
Nanoha dness and educed Young modulus cou ses ac oss he Inconel 625 laye on he
ben ube— he a ea wi h maximum comp ess s esses (IR).
3.3. Analysis o Clad Laye Mic os uc u e a e Bending
The mic os uc u e o Inconel 625 laye s a ec ed by he bending p ocess is documen ed
in Figu e 9, which was gene a ed using a con ocal mic oscope (Olympus Lex OLS5100,
Ma e ials 2023,16, 6796 9 o 15
Olympus IMS, Webs e , TX, USA). The s uc u e o he o iginal laye una ec ed by bending
is shown in Figu e 9a o compa e changes a e bending in he OR (Figu e 9b) o IR a ea
(Figu e 9c). As desc ibed in mo e de ail in Sec ion 2.1, he mic os uc u e o he laye is
p ima ily o med by dend i es o he
γ
phase. The shape and mo phology o dend i es a e
he mos signi ican indica o s o mic os uc u al changes due o bending.
Ma e ials 2023, 16, x FOR PEER REVIEW 9 o 15
OLS5100, Olympus IMS, Webs e , TX, USA). The s uc u e o he o iginal laye unaffec ed
by bending is shown in Figu e 9a o compa e changes a e bending in he OR (Figu e 9b)
o IR a ea (Figu e 9c). As desc ibed in mo e de ail in Sec ion 2.1, he mic os uc u e o he
laye is p ima ily o med by dend i es o he γ phase. The shape and mo phology o den-
d i es a e he mos signi ican indica o s o mic os uc u al changes due o bending.
In he a ea whe e ensile s esses a e ac ing, he dend i es a e s e ched in he di ec-
ion o hei seconda y axes, called a ms (see Figu e 9b). The p ima y dend i e axes a e
also na owe bu emain s aigh , wi hou de o ma ion o cu a u e. In he a ea o com-
p essi e s esses (depic ed in Figu e 9c), he mic os uc u e is no iceably mo e affec ed
compa ed o OR. The a ms o he dend i es a e almos indis inc as a esul o de o ma ion
by comp essed s esses. The dend i e axes a e no longe s aigh bu ben wi h a ce ain
cu a u e.
(a) (b) (c)
Figu e 9. Mic os uc u e o Inconel 625 clad laye and i s change a e bending. (a) Sample wi hou
bend (NB), (b) a ea o maximum ensile s esses (OR), and (c) a ea o maximum comp essi e s esses
(IR).
The men ioned conclusions a e also con i med by he quan i a i e mic os uc u e anal-
ysis pe o med using he analy ical so wa e S eam o he Olympus Lex OLS5100 (Table
3). The o iginal mic os uc u e pho og aphs we e p ocessed in o de o highligh dend i e
bounda ies h ough hei ans o ma ion o he wo-colo scheme, which is mos sui able o
he quan i a i e analysis. A e p ocessing, he dend i es we e mo e p onounced wi h
sha pe bo de s. The in e dend i ic space was simpli ied o a ma ix, neglec ing he p esence
o seconda y phases. The geome ic pa ame e s o he dend i es (wid h, leng h) we e hen
e alua ed. In he case o he IR egion, he leng h o he a c in which he dend i es we e
de o med was conside ed o be he leng h o he dend i e. Addi ionally, phase analysis was
pe o med o de e mine he sha e o dend i es and he ma ix.
The wid h o he dend i es ollows he ype o applied s ess. I is signi ican ly la ge
in he ensile a ea and, con e sely, smalle in he p essu e a ea. The leng hs o he den-
d i es do no change signi ican ly in indi idual in es iga ed cases, e en hough, in he IR
egion, hey a e de o med in o he shape o an a c. In e ms o he phase sha e, he e was
a dec ease in he p opo ion o he in e dend i ic space (ma ix) in bo h a e -bending
cases compa ed o he s a e wi hou bending. In wo a e -bending cases, dend i es a e
diffe en ly de o med acco ding o he applied s ess. Howe e , he sha e o he dend i ic
a ea is almos he same in bo h cases.
Table 3. Quan i a i e mic oscopy pa ame e s o in es iga ed dend i es.
Pa ame e NB OR IR
Dend i e wid h (µm) 9.93 ± 1.11 17.7 ± 0.8 4.75 ± 1.24
Dend i e leng h (µm) 51.39 ± 1.68 48.94 ± 2.8 52.72 ± 7.45
A ea o he dend i es (%) 42.38 54.03 56.75
Ma ix (%) 57.62 45.97 43.25
Figu e 9.
Mic os uc u e o Inconel 625 clad laye and i s change a e bending. (
a
) Sample wi h-
ou bend (NB), (
b
) a ea o maximum ensile s esses (OR), and (
c
) a ea o maximum comp essi e
s esses (IR).
In he a ea whe e ensile s esses a e ac ing, he dend i es a e s e ched in he di ec ion
o hei seconda y axes, called a ms (see Figu e 9b). The p ima y dend i e axes a e also
na owe bu emain s aigh , wi hou de o ma ion o cu a u e. In he a ea o comp essi e
s esses (depic ed in Figu e 9c), he mic os uc u e is no iceably mo e a ec ed compa ed o
OR. The a ms o he dend i es a e almos indis inc as a esul o de o ma ion by comp essed
s esses. The dend i e axes a e no longe s aigh bu ben wi h a ce ain cu a u e.
The men ioned conclusions a e also con i med by he quan i a i e mic os uc u e
analysis pe o med using he analy ical so wa e S eam o he Olympus Lex OLS5100
(Table 3). The o iginal mic os uc u e pho og aphs we e p ocessed in o de o highligh
dend i e bounda ies h ough hei ans o ma ion o he wo-colo scheme, which is mos
sui able o he quan i a i e analysis. A e p ocessing, he dend i es we e mo e p onounced
wi h sha pe bo de s. The in e dend i ic space was simpli ied o a ma ix, neglec ing he
p esence o seconda y phases. The geome ic pa ame e s o he dend i es (wid h, leng h)
we e hen e alua ed. In he case o he IR egion, he leng h o he a c in which he dend i es
we e de o med was conside ed o be he leng h o he dend i e. Addi ionally, phase analysis
was pe o med o de e mine he sha e o dend i es and he ma ix.
Table 3. Quan i a i e mic oscopy pa ame e s o in es iga ed dend i es.
Pa ame e NB OR IR
Dend i e wid h (µm) 9.93 ±1.11 17.7 ±0.8 4.75 ±1.24
Dend i e leng h (µm) 51.39 ±1.68 48.94 ±2.8 52.72 ±7.45
A ea o he dend i es (%) 42.38 54.03 56.75
Ma ix (%) 57.62 45.97 43.25
The wid h o he dend i es ollows he ype o applied s ess. I is signi ican ly la ge
in he ensile a ea and, con e sely, smalle in he p essu e a ea. The leng hs o he dend i es
do no change signi ican ly in indi idual in es iga ed cases, e en hough, in he IR egion,
hey a e de o med in o he shape o an a c. In e ms o he phase sha e, he e was a dec ease
in he p opo ion o he in e dend i ic space (ma ix) in bo h a e -bending cases compa ed
o he s a e wi hou bending. In wo a e -bending cases, dend i es a e di e en ly de o med
acco ding o he applied s ess. Howe e , he sha e o he dend i ic a ea is almos he same
in bo h cases.