Silicon carbide (SiC) is an important ceramic material usually found in polycrystalline form with grain boundary thickness ranging from a few nanometers to a few hundred nanometers and grains with multiple orientations with sizes of the order of few micrometers. The present work focuses on analyzing how the interplay between different orientations of SiC grains and different grain boundary thicknesses can be exploited for targeted improvement in the fracture resistance properties of SiC. Crack propagation simulations using the cohesive finite element method (CFEM) are performed on the finite element meshes developed on experimentally processed SiC morphologies. Analyses were performed at two different length scales: 300 μm × 60 μm (scale-1:Microscale) and 75 μm × 15 μm (scale-2:Mesoscale). Lower resolution microstructure at scale-1 does not explicitly consider the presence of grain boundaries (GBs). Higher resolution microstructure at scale-2 explicitly models GBs. Results indicate that the effect of change in grain orientation is on crack path only. The fracture resistance is not significantly affected. The presence of GBs may directly aid in strengthening a microstructure’s fracture resistance. However, indirectly it may weaken a microstructure by favoring the formation of microcracks. Significantly higher crack formation in grain interior while lower interfacial energy dissipation in comparison to interfaces indicates overall lower fracture strength of grain interiors in comparison to interfaces. If GBs are not accounted for, the second most influencing factor affecting fracture strength is the average grains size. Overall, it is mainly the GBs not the grain orientation distribution and grain size that significantly affects fracture strength.

References

References
1.
Ajayan
,
P. M.
,
Schadler
,
L. S.
, and
Braun
,
P. V.
, 2003,
Nanocomposite Science and Technology
,
Wiley-VCH
,
Weinheim, Germany
.
2.
Tian
,
Y.
, and
Shin
,
Y. C.
, 2007, “
Multiscale Finite Element Modeling of Silicon Nitride Ceramics Undergoing Laser-Assisted Machining
,”
J. Manuf. Sci. Eng.
,
129
(2), pp.
287
295
.
3.
Raiser
,
G. F.
,
Wise
,
J. L.
,
Clifton
,
R. J.
,
Grady
,
D. E.
, and
Cox
,
D. E.
, 1994, “
Plate Impact Response of Ceramics and Glasses
,”
J. Appl. Phys.
,
75
(
8
), pp.
3862
3869
.
4.
Krstic
,
V. D.
, 1988, “
Grain Size Dependence of Fracture Strength in Anisotropic Brittle Solids
,”
J. Mater. Sci.
23
, pp.
259
266
.
5.
Zavattieri
,
P. D.
,
Raghuram
,
P. V.
, and
Espinosa
,
H. D.
, 2001, “
A Computational Model of Ceramic Microstructures Subjected to Multi-Axial Dynamic Loading
,”
J. Mech. Phys. Solids
,
49
, pp.
27
68
.
6.
Sands
,
C. M.
,
Henderson
,
R. J.
, and
Chandler
,
H. W.
, 2007, “
A Three Dimensional Computational Model of the Mechanical Response of a Dual-Phase Ceramic
,”
Comput. Mater. Sci.
,
39
, pp.
862
870
.
7.
Zhou
,
Y.
,
Hirao
,
K.
,
Toriyama
,
M.
,
Yamauchi
,
Y.
, and
Kanzaki
,
S.
, 2001, “
Effects of Intergranular Phase Chemistry on the Microstructure and Mechanical Properties of Silicon Carbide Ceramics Densified With Rare-Earth Oxide and Alumina Additions
,”
J. Am. Ceram. Soc.
,
84
(
7
), pp.
1642
1644
.
8.
Tomar
,
V.
, 2008a, “
Analyses of the Role of Grain Boundaries in Mesoscale Dynamic Fracture Resistance of SiC-Si3N4 Intergranular Nanocomposites
,”
Eng. Fract. Mech.
,
75
, pp.
4501
4512
.
9.
Tomar
,
V.
, 2008b, “
Analyses of the Role of the Second Phase SiC Particles in Microstructure Dependent Fracture Resistance Variation of SiC-Si3N4 Nanocomposites
,”
Modell. Simul. Mater. Sci. Eng.
,
16
, p.
035001
.
10.
Tomar
,
V.
,
Zhai
,
J.
and
Zhou
,
M.
, 2004, “
Bounds for Element Size in a Variable Stiffness Cohesive Finite Element Model
,”
Int. J. Numer. Methods Eng.
,
61
, pp.
1894
1920
.
11.
Latapie
,
A.
, and
Farkas
,
D.
, 2004, “
Molecular Dynamics Investigation of the Fracture Behavior of Nanocrystalline α-Fe
,”
Phys. Rev. B
,
69
, p.
134110
.
12.
Farkas
,
D.
,
Willemann
,
M.
and
Hyde
,
B.
, 2005, “
Atomistic Mechanisms of Fatigue in Nanocrystalline Metals
,”
Phys. Rev. Lett.
,
94
, p.
165502
.
13.
Woetting
,
G.
,
Caspers
,
B.
,
Gugel
,
E.
, and
Westerheide
,
R.
, 2000, “
High-Temperature Properties of SiC-Si3N4 Particle Composites
,”
J. Eng. Gas Turbines Power
,
122
(1), pp.
8
12
.
14.
Klopp
,
R. W.
, and
Shockey
,
D. A.
, (1991). “
The Strength Behavior of Granulated Silicon Carbide at High Strain Rates and Confining Pressure
,”
J. Appl. Phys.
,
70
(
12
), pp.
7318
7326
.
15.
Holmquist
,
T. J.
, and
Johnson
,
G. R.
, 2002, “
Response of Silicon Carbide to High Velocity Impact
,”
J. Appl. Phys.
,
91
(
9
), pp.
5858
5866
.
16.
Walker
,
J.
, 2003, “
Analytically Modeling Hypervelocity Penetration of Thick Ceramic Targets
,”
Int. J. Impact Eng.
,
29
(
1–10
), pp.
747
755
.
17.
Loubens
,
A.
,
Rivero
,
C.
,
Boivin
,
P.
,
Charlet
,
B.
,
Fortunier
,
R.
, and
Thomas
,
O.
, 2005, “
Investigation of Local Stress Fields: Finite Element Modeling and High-Resolution X-Ray Diffraction
,”
875
, pp.
229
234
18.
Yang
,
J.
,
Yang
,
J.-F.
,
Shan
,
S.-Y.
,
Gao
,
J.-Q.
, and
Ohji
,
T.
, 2006, “
Effect of Sintering Additives on Microstructure and Mechanical Properties of Porous Silicon Nitride Ceramics
,”
J. Am. Ceram. Soc.
,
89
(
12
), pp.
3843
3845
.
19.
Xu
,
X. P.
, and
Needleman
,
A.
, 1994, “
Numerical Simulations of Fast Crack Growth in Brittle Solids
,”
J. Mech. Phys. Solids
,
42
, pp.
1397
1434
.
20.
Sorensen
,
B. F.
, and
Jacobsen
,
T. K.
, 2003, “
Determination of Cohesive Laws by the J Integral Approach
,”
Eng. Fract. Mech.
,
70
, pp.
1841
1858
.
21.
Cornec
,
A.
,
Scheider
,
I.
, and
Schwalbe
,
K.-H.
, 2003, “
On the Practical Application of the Cohesive Zone Model
,”
Eng. Fract. Mech.
70
, pp.
1963
1987
.
22.
Espinosa
,
H. D.
,
Dwivedi
,
S.
, and
Lu
,
H.-C.
, 2000, “
Modeling Impact Induced Delamination of Woven Fiber Reinforced Composites With Contact/Cohesive Laws
,”
Comput. Methods Appl. Mech. Eng.
,
183
, pp.
259
290
.
23.
Belytschko
,
T.
,
Chiapetta
,
R. L.
, and
Bartel
,
H. D.
, 1976, “
Efficient Large Scale Non-Linear Transient Analysis by Finite Elements
,”
Int. J. Numer. Methods Eng.
,
10
, pp.
579
596.
24.
Zhai
,
J.
, and
Zhou
,
M.
, 2000, “
Finite Element Analysis of Micromechanical Failure Modes in Heterogeneous Brittle Solids
,”
Int. J. Fract.
,
101
, pp.
161
180
.
25.
Rice
,
R. W.
, and
Freiman
,
S. W.
, 1981, “
Grain-Size Dependence of Fracture Energy in Ceramics: II, A Model for Noncubic Materials
,”
J. Am. Ceram. Soc.
,
64
(6), pp.
350
354
.
26.
Coppola
,
J. A.
, and
Bradt
,
R. C.
, 1972, “
Measurement of Fracture Surface Energy of SiC
,”
J. Am. Ceram. Soc.
,
55
(9), pp.
455
460
.
You do not currently have access to this content.