H.Uzun, N. Ait1nkök, R.Yalmaz
In terms of the rule of mixtures
layer/core in the materia1, thus the 0.2 °/o yield
% yield strength and tensile strength
strength and tensile strength of FGMs are given by
given in Table theory, the
0.2
2.
of FGMs depend on the area fraction of each
crFGM
(J'
TS
(J laycr 1
== a
I'Ci.\1
Alayer 1
O 2%YS
0.2% YS
A
JS tnyı:r 1
AFGM
ic�vıtr
1
---
A
+
+
a
fo ver
layer2
Alayer 2
T\' 2
!•(i \/
Alayer2
0'0 2%YS
---
A PG:\!
AFGM
the following expressions :
+
·
·
·
\'
T
+ . . . . + O" l�yc:r t 11)
·
Alayer( n)
+cr 0.2%_YS l ayer( n)
A1
(2)
A FG�f
aya 1 n )
(3)
A FGM
where; 0.2°/o YS cr FGM 0.2% YS
cr la�er 1
'
•
(J
'
•
O. 2% YS layeı· (
n
})
=the
O.2 % yield strength of
=the
0.2 % yield strength of each
=
r'\ TS V laycr
1
'
• •
J.
/mu 1 ., .
The
� rs ,V l::ı}eı· (
. .. '
n
constituent layer/core in FGM
the tensile strength of FGM
=the tensite stress of each constituent layer/core in FGM
)
A'·�\ ı:r( ll)
calculated
FGM
and
=the area fraction of each constituent Jayer/core
experimental
0.2
%
yield
strength and tensite strength of FGMs with different
o/oSiC series. The percentage differences between
calculated and experimental values for the 30 %SiC
SiC volun1e fraction are compared in Figures 1 and
series are higher than for the
values are within 20 o/o of the experimental values
agreement between experimental and calculated
°/o.
of agreement. This indicates that when the SiC
using a
volume fraction of the surface layer exceeds 20
of mixtures approach are generally
vol%, the increasing aınounts of agglomeration,
2, respectively. The calculated
O.2 o/o
yield strength
for 20 °/oSiC and 30 o/oSiC series, except for the
30.15.Al. double core FGM which is within The tensite simple within
rule
2
strength
values calculated
25
o/o of the experimental values for the 20
the
values, the 30 ��SiC series demonstrate a poor leve1
porosity,
ı
poor
consoJidation
and
delaınjnation
CExperim ental results
[ •Calculated results
-
...... ..
series. While
%SiC series FGMs exhibits very good
20
350 ('O a. �
20 %SjC
300
.s:
�
C) c:
�
�
tJ)
250
'"O -
Q)
·-
>-
� o
N
200
•
o
150
...__
_......
_
20 %SiC - Al-2124 single core FGM
20 %SiC-10 %SiC - Al-2124 double core
FGM
Figure 1. Comparison of experimental and calcuJated
30 %SiC- Al-2124 sıngle core
FGM
30 %SiC-
15
%SiC - Al-2124 double core FGM
0.2 % yield strength results for FGMs.
87