Characterization and control of the fiber-matrix interface in ceramic ...

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Figure 10.18. 10.19. 10.20. 10. 21. . 10.22. 10.23. Load-displacement curves and Fracture surfaces of specimens fabricated from Nicalon fibers coated with boron-containing interinediate layers prior to infiltration: (a) elemental boron and (b) boron ni-tride from diborane and aminoni a . . . . . . . . . . . . . Higher-magnification SEM analysis of fractured boroncoated fiber specimens showing evidence of chemical interaction at the fiber-matrix interface and within the fiber . SEM micrographs of indented Nicalon fibers with (a> a boron coating arid (b) a boron nitride layer . . . . . AES analysis of fracture surface features for an Sic composite specimen containing Nicalon fibers coated with a boron intermediate layer . . . . . . . . . . . . . . . . Load-displacement curve and fracture surfaces of specimens fabricated from Nicalon fibers coated with a molybdenum intermediate layer prior to infiltration . . . . SEM mi.crographs of indented molybdenum-coated Nicalon fibers in an Sic matrix . . . . . . . . . . . . . . . . Page 129 131 13h 135 138 139 10.24. AES analysis of fracture surface features for an Sic composite specimen containing Nicalon fibers coat:ed with a molybdenum intermediate layer . . . . . . . . . . lh2 10.25. Coating fracture observed during testing of AVCO filainents: (a) untreated and (h) with a carbon intermediate coating . . . . . . . . . . . . . . . . . . 143 10.26. SEM photomicrographs of Sic-coated Nicalon filaments . . . 145 11.1. 11.2. 11.3. 11.4, The effect of varying thickness of pyrocarbon on the fracture of Sic composite sampl-es: (a) CVI-178, uncoated; (b) CVI-175, 0.10-,urn carbon layer; (c) CVI-171, 0.17-pm carbon layer; and (d) CVI-174, O.28-pm carbon layer . . . . . . . . . . . . . . . . . . . The predicted stress-strain curve for a fiber-reinforced composite exhibiting single-fracture behavior . . . . . . . The theoretical stress-strain curve for a composite exhibiting multiple-matrix fracture . . . . . . . . . . . . The apparent mechanical behavior of the fibers and matrix compared with an actual flexure CUKV~ for a 40 vol % Nicalon fiber-SiC coniposite . . . . . . . . . . . 153 156 157 159 xii
Figure Page 11.5. The diffusion coefficient for selected elements in selected materials .................... 164 11.6. The nonlinear distribution of shear stresses at the fiber-matrix interface . . . . . . . . . . . . . . . . . . 170 11.7. Stress blocks in flexure: (a) perfectly elastic material arid (b) material that is elastic in compression and plastic in tension . . . . . . . . . . . . 176 xiii
Page 3: ORNL/TM-11039 Metals and Ceramics D
Page 6 and 7: Page 9.3 Composite Fabrication . .
Page 9: LIST OF TABLES Table Page 5,l. Prop
Page 12 and 13: Figure 8.3. 9.1.. 9.2. 9.3. 9.4. 9.
Page 17 and 18: ACKNOWLEDGMENTS The author wishes t
Page 19 and 20: CWCTERIZATION AND CONTROL OF THE FI
Page 21: 1. INTRODUCTION During the last sev
Page 24 and 25: The development of low-density, hig
Page 27 and 28: 3. FABRICATION TECHNIQUES 3.1 Intro
Page 29 and 30: 11 isostatic pressing (HIP), can be
Page 31: 13 utilizing the comparatively low-
Page 34 and 35: 16 ORN L- DWG 85- 4 i 4 18RS HEAT1
Page 37 and 38: 5. COMPOSITE DESIGN 5.1 Introductio
Page 39 and 40: 21 5,2 Mechanical Considerations Th
Page 41 and 42: 23 GRNL-DWG 88-74 26 Figure 5.1. Th
Page 43 and 44: 25 Equation (6) shows that the stre
Page 45 and 46: 27 of reinforcement. There are two
Page 47 and 48: 29 in strength. Conversely, the fib
Page 49 and 50: -I_- Table 5.2. Thermally induced a
Page 51 and 52: 33 1.2 ID 0.8 ;.r 1 e fi v 0.6 a4 Q
Page 53: 35 will affect the interface and, t
Page 56 and 57: 38 fiber-matrix bonding; thus, a fu
Page 58 and 59: 40 In the analysis of the mechanica
Page 60 and 61: 42 1.2 I .o .6 - E f aa '3 0.6 cn 3
Page 62 and 63: 44 will result in the matrix being
Page 64 and 65:
I I MATRIX MATRIX Figure 7.1. Schem
Page 66 and 67:
48 F = 2a2H, where H is the hardnes
Page 68 and 69:
50 OWL-PHOTO 6866-86 i d c I 20pm F
Page 70 and 71:
52 where Af is the surface area of
Page 72 and 73:
54 Figure 7.4. Tensile and shear st
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56 I I I / -c rc -c / . Om / / I /
Page 76 and 77:
58 ORNL-OWG 87-i 8234 F Figure 7.7.
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coating and the distribution of she
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62 O m PHOTO 6676-87 i SIC FIBERS -
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the composite, therefore an interme
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methane as the reactant and is, thu
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9. EXPERIMENTAL PROCEDURES 9.1 Depo
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71 furnace. The furnace is, therefo
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73 further protection. A 6.5-cm-dia
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76 of the specimen slowly decreased
Page 96 and 97:
78 The programmer is also equipped
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80 graphite holders through multipl
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82 temperature by simply switching
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84 ORNk DWG 87- 4494 3 METAL LOGR A
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86 9.5 Fracture Surface Analvsis Th
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88 treated and untreated halves wer
Page 108 and 109:
90 9.8.2 Tensile testinq In an init
Page 110 and 111:
92 ORNL-DUG 85-11767R.2 ? ! 2 f CEN
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94 fracture of individual Nicalon f
Page 114:
96 Figure 10.1. SiC-infiltrated Nic
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99 compared with the dimensions acq
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101 Table 10.3. Strength and modulu
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100 ORNL- DWG 87-1 6292 R CVI-I73 7
Page 123 and 124:
BULK FIBER SAMPLE NO. 173: FIBER SU
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107 similar samples show the film o
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Figure 10.7. SEM micrographs showin
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111 Table 10.4. Thermochemical eval
Page 131 and 132:
100 ORNL-DUG 87-15969R CVI- 170 75
Page 133 and 134:
115 Analysis conversion of of the m
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117 A 1 I S N 31 N I I'd I LN 3H 3
Page 137 and 138:
119 n 0 W n 9 v P n w- n v
Page 139 and 140:
121 s m f c I m z - Ir 2 a 0 9 In u
Page 141 and 142:
Figure 10.14. SEM micrographs of in
Page 143 and 144:
J ORNL-DWC 88-6289 z cF u) w I- z O
Page 145 and 146:
127 300 I CVI-480 I I 1 0 R N L-DWG
Page 147 and 148:
io0 I I I I CVI- 172 75 - - 0 z v -
Page 149 and 150:
131 RAL 033021 RAL 033023 Figure 10
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133 include: the reaction of boron
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136 that BN coatings react with the
Page 156 and 157:
75 7 ORNL-DWG 87-48234 50 - - c5 z
Page 158 and 159:
140 Table 10.9. Thermochemical eval
Page 160 and 161:
OANL-bwo 88-9025 ORNL-DWG 66-9027 I
Page 162 and 163:
144 uncoated tows were 14 k 2 pm; t
Page 165 and 166:
11. DISCUSSION 11.1 Constituent Pro
Page 167 and 168:
149 The properties of CVD Sic have
Page 169 and 170:
151 11.2.1 Matrix cracking In the N
Page 171 and 172:
153 OWL-DWG 88-10677 CVI- (78 22 I
Page 173 and 174:
155 Table 11.3. Property comparison
Page 175 and 176:
157 a f ““f f- L c I Figure 11.
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159
Page 179 and 180:
161 The equations demonstrate that
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163 calculations of the matrix depo
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165 In four of the samples, the fib
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167 Table 11.4. Properties of glass
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169 rare-earth magnets and coils to
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171 stress fields along the fiber i
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173 11.3.2 Tensile testinp, The use
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17 5 contraction have been ignored,
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177 the system, and when the result
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180 reduces fiber strength. The str
Page 200 and 201:
182 15. R. A. J. Sambell, D. H. Bow
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184 41. A. J. Caputo et al., "Fiber
Page 204 and 205:
186 71, N. F. DOW, Study of Stresse
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188 98. M. H. Rawlins et al., "Inte
Page 208 and 209:
190 125. R. Warren and C-H. Anderss
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192 155. M. F. Doerner and W, D. Ni
Page 213 and 214:
APPENDIX A. AUGER ELECTRON SPECTROS
Page 215:
APPENDIX B DETAILS OF THE FIBER-SHE
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200 Those for the fiber (primed) ar
Page 220 and 221:
202 89-92. 93. 94. 95" 96. 97. 98-9
Page 222 and 223:
204 130-133. E. I. DUPONT DE NEMOUR
Page 224 and 225:
206 173. NATIONAL ACADEMY OF SCIENC
Page 226 and 227:
208 203 - 204. 20s. 206 - 207. 208.
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