Biomedical Engineering Reference
In-Depth Information
Grain size,
G
(
m)
µ
100 50 20
10
5 4
2
1
90
Slope
=
3.5 MPa
m
1/2
600
Slope
=
2.3 MPa m
1/2
80
500
70
60
400
50
300
40
30
200
Rice, earlier survey
20
100
10
0
0
0
10
20
30
40
50
60
70
80
90
100
(Grain size)
-1/2
,
-1/2
(cm
-1/2
)
G
Figure 10.20.
Strength-grain size relationship for alumina: circles indicate failure where
homogeneous microstructures are involved, squares where exaggerated grains were present.
Symbols with crosses represent specimens ground after hot pressing [Rice, 1997].
30
25
20
1650°C
15
10
1550°C
5
1450°C
0
0
10
20
30
40
50
60
Time (min)
Figure 10.21.
Al
2
O
3
grain size as a function of the sintering cycle. [Anné, 2005a].
10.7.4 Observation of Processing Defects in FGM Materials
Al
2
O
3
/ZrO
2
FGM discs, made by EPD as described in section 10.5, are sintered
for one hour at 1550 °C. The heating and cooling rate is 3 °C/min. After sintering,
cross-sections are analyzed by scanning electron microscopy (SEM-FEG FEI
XL-30) and the composition profi les are measured by means of EPMA.
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