If the b onsideration Plane view f 200 nm; fore the crac FESEM pl he curvatur d.. studen energy relea interfacial t ack pattern kness of 500 and toward f wedge inde ack front.. Interf f
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F
t
t
d
b
f
o
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Fig 4.13: P
thickness of
taken as bef
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shown in F
thickness ca
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1
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f
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ck kinks int
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g Haiyan, M
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M.Sc studen
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ack pattern kness of 500 and toward f
wedge inde ack front T
s used to ob the origin o
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by SEM*:
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entation im The followin btain the co
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mpression is
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Fig 4.14: F
order polyn
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Fig 4.15: C
thickness ra
FESEM plan
nomial func
f the crack f
Curvature
anging from
ne-view ima ction is fit front [2]
of interfaci
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age of delam tted to the
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minated are crack fron
front determ
a on 500nm
nt in order
mined for t
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r to determ
the BD film
Chapter 4
A ninth-mine the
ms with
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B
a
m
1
f
i
t
m
t
r
c
f
Fig 4.16: F
interfacial c
BD film: a
and (d) the
To
measuremen
1000nm) F
film thickne
interfacial c
this suggest
mode, and
thickness is
reaches a pl
circular; thu
film, the cra
ESEM plan
crack front o
slightly cur
1000 nm BD
determine
nts are mad
ig.4.15 show
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crack front
ts that the c
the plane
increased t
lateau at ab
us the circul
ack front is
ne-view ima
on (a) the 10 rved crack f
D film: alm
the curvatu
de for each
ws the relat
n be seen i
is very stra critical buck strain cond
to about 500
bout 0.51 µm
lar buckling slightly cu
ages of the w
00 nm BD f front; (c) th most circular
ure of the
h BD film tionship bet
in Fig.4.16(
aight and th kling stress dition is fu
0 nm or mor
m-1 (Fig.4.1
g mode sho urved (Fig.4
wedge inden film: a straig
he 500 nm B
r delaminati
delaminati thickness tween the cu (a), for a B
he curvatur should follo ulfilled In
re (Fig.4.16 15), and the uld be adop 4.16(b)); hen
ntation sites ght crack fr
BD film: a ion [2]
ion crack f (100nm, 30 urvature of
BD film ≤
e is closed
ow the stra contrast, w 6(c) and 4.1
e delaminati pted For th nce the crit
C
s and the as ront; (b) the curved crac
front, at le 00nm, 500n
f crack front
100 nm th
to zero (Fi ight-sided b when the B 6(d)), the cu ion shape is
he 300 nm th ical bucklin
Chapter 4
sociated
e 300 nm
ck front,
east five
nm, and
t and the hick, the ig.4.15); buckling
BD film urvature
s almost hick BD
ng stress