Abstract

Nanoindentation was used to measure the elastic modulus (E) and hardness (H) of the matrix materials of three ceramic composites reinforced with woven Nicalon fiber fabrics. The matrices included: (1) alumina produced by the Dimox process; (2) silicon carbide synthesized by chemical vapor infiltration; and (3) a SiC/BN material produced by polymer infiltration pyrolysis. The elastic moduli and hardnesses of the matrices of all three materials were found to be significantly lower than bulk ceramics of similar composition, probably due to porosity in the matrix and/or incomplete conversion of the infiltration materials to ceramic. Each of the composites was exposed to air at 750°C for 64 h, and measurements of E and H were made. The silicon carbide matrix was essentially unaffected, but two other materials exhibited significant reductions in both E and H caused by thermal exposure.

References

1.
Lamicq
,
P. J.
, “
Thermostructural CMC's: An Overview of the French Experience
,” in
High-Temperature Ceramic-Matrix Composites, of Ceramic Transactions
, Vol.
57
,
A. G.
Evans
and
R.
Naslain
, Eds.,
American Ceramic Society
,
1995
, pp.
1
-
11
.
2.
Spriet
,
P.
,
Boury
,
D.
, and
Habarou
,
G.
, “
Military Turbojet Component Design and Validation with Thermostructural Composite Material
,” in
High-Temperature Ceramic-Matrix Composites, of Ceramic Transactions
, Vol.
57
,
A. G.
Evans
and
R.
Naslain
, Eds.,
American Ceramic Society
,
1995
, pp.
191
-
202
.
3.
Kobayashi
,
H.
,
Todoroki
,
A.
, and
Nakamura
,
H.
, “
Fracture Toughness Determination of SiC/SiC Fabric Composites
,” in
High-Temperature Ceramic-Matrix Composites, of Ceramic Transactions
, Vol.
57
,
A. G.
Evans
and
R.
Naslain
, Eds.,
American Ceramic Society
,
1995
, pp.
431
-
436
.
4.
Pharr
,
G. M.
,
Material Science and Engineering A
, Vol.
253
,
1998
, pp.
151
-
159
.
5.
Drissi-Habti
,
M.
and
Nakano
,
K.
,
Composites Science and Technology
 0266-3538, Vol.
57
,
1997
, pp.
1483
-
1489
.
6.
Davidson
,
D. L.
,
Journal of Metals
 0148-6608, Vol.
47
, No.
10
,
1995
, pp.
46
-
50
and
81
-
82
.
7.
Davidson
,
D. L.
, “
Fracture Mechanics as Influenced by Environment in Textile Reinforced Ceramic Matrix Composites
,”
Technical Report
,
Office of Naval Research
,
06
1999
.
8.
Chawla
,
N.
,
Holmes
,
J. W.
, and
Mansfield
,
J. F.
,
Materials Characterization
 1044-5803, Vol.
35
,
1995
, pp.
199
-
206
.
9.
Bleay
,
S. M.
,
Chapman
,
A. R.
,
Love
,
G.
, and
Scott
,
V. D.
,
Journal of Material Science
, Vol.
27
,
1992
, pp.
5389
-
5396
.
10.
Oliver
,
W. C.
and
Pharr
,
G. M.
,
Journal of Material Research
, Vol.
7
,
1992
, pp.
1564
-
1583
.
11.
Duan
and
Steinbrech
,
Journal of European Ceramic Society
, Vol.
18
,
1998
, pp.
87
-
93
.
12.
Bolshakov
,
A.
and
Pharr
,
G. M.
,
Journal of Material Research
, Vol.
13
,
1998
, pp.
1049
-
1058
.
13.
Lange
,
F. F.
,
Tu
,
W. C.
, and
Evans
,
A. G.
,
Material Science and Engineering
,
1995
, pp.
145
-
150
.
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