Process induced micro-scale evolutions can greatly influence the strength and resilience of a high temperature ceramic and intermetallic component. A micromechanical study, based on a unit cell approach, is carried out in the present work to investigate these evolutions during compaction of titanium aluminide multi-phase intermetallics at elevated temperatures. The quasi-coupled unit cell analysis can provide an avenue for investigating scalability and migratability of laboratory results to full scale productions with perturbed material compositions. Effects of various macro-scale process design considerations (e.g., tooling stiffness, spatial distribution of thermal fields) on micro-scale evolutions are investigated in detail. It has been observed that a more economic (and usually more flexible) container increases the likelihood of micro-crack nucleations, while spatially non-uniform intra-particle thermal fields can be utilized to alleviate processing induced micro-cracks in the final compacted product. Possibilities for process design modifications are also discussed.

1.
ABAQUS Manual for Version 5.2, 1992, published by Hibbitt, Karlsson & Sorensen, Inc.
2.
Akisanya
A. R.
,
Cocks
A. C. F.
, and
Fleck
N. A.
,
1994
, “
Hydrostatic Compaction of Cylindrical Particles
,”
J. Mech. Phys. Sol.
, Vol.
42
, pp.
1067
1085
.
3.
Ashby
M. F.
,
1974
, “
A First Report on Sintering Diagrams
,”
Acta Metall.
, Vol.
22
, pp.
275
289
.
4.
Arthurs
T. C.
,
Mostaghaci
H.
, and
Murphy
J. G.
,
1990
, “
The Effect of Forming Processes on the Sintering Behavior of Si3N4/TiB2 Composites
,”
Ceram. Eng. Sci. Proc
, Vol.
11
, pp.
1778
1789
.
5.
Benson
D. J.
,
1992
, “
Computational Methods in Lagrangian and Eulerian Hydrocodes
,”
Comp. Meth. Appl. Mech. Engng.
, Vol.
99
, pp.
235
394
.
6.
Benson, D. J., 1993a, “Application of an Eulerian Finite Element Method to Problems in Micromechanics,” Adv. Comp. Meth. for Mat. Modelling, ASME AMD-180, pp. 1–11.
7.
Benson, D. J., 1993b, “An Analysis of Void Distribution Effects on the Dynamic Growth and Coalescence of Voids in Ductile Metals,” J. Mech. Phys. Sol., in press.
8.
Chandra
A.
, and
Tvergaard
V.
,
1993
, “
Void Nucleation and Growth During Plane Strain Extrusion
,”
Int. J. Damage Mech.
, Vol.
2
, pp.
330
348
.
9.
Chokshi
A. H.
, and
Meyers
M. A.
,
1990
, “
The Prospects for Superplasticity at High Strain Rates: Preliminary Considerations and an Example
,”
Scripta Metallurgica et Materialia
, Vol.
24
, pp.
605
610
.
10.
Dahms
M.
,
Seeger
J.
,
Smarsly
W.
, and
Wildhagen
B.
,
1991
, “
Titaniumaluminides by Hot Isostatic Pressing of Cold Extruded Titanium Aluminium Powder Mixtures
,”
ISIJ Int.
, Vol.
31
, pp.
1093
1099
.
11.
Dash
J. G.
,
1989
, “
Surface Melting
,”
Contemporary Physics
, Vol.
30
, pp.
89
100
.
12.
Fischer
E.
,
1989
, “
20 Years of P/M Compression Forming
,”
PMI
, Vol.
21
, pp.
23
28
.
13.
Fleck
N. A.
,
Kuhn
L. T.
, and
McMeeking
R. M.
,
1992
, “
Yielding of Metal Powder Bonded by Isolated Contacts
,”
J. Mech. Phys. Sol.
, Vol.
40
, pp.
1139
1162
.
14.
Ferreira
A.
,
Meyers
M. A.
,
Thadhani
N. N.
,
Chang
S. N.
, and
Kough
J. R.
,
1991
, “
Dynamic Compaction of Titanium Aluminides by Explosively Generated Shock Waves: Experimental and Material Systems
,”
Met. Trans.
, Vol.
22A
, pp.
685
695
.
15.
Froes
F. H.
,
Suryanarayana
C.
, and
Eliezer
D.
,
1991
, “
Production, Characteristics and Commercialization of Titanium Aluminides
,”
ISIJ Int.
, Vol.
31
, pp.
1235
1248
.
16.
Groza
J. R.
,
1993
, “
Nonconventional Pressure-assisted Powder Consolidation Methods
,”
Journal of Materials Engineering and Performance
, Vol.
3
, pp.
283
290
.
17.
Gurson
A. L.
,
1977
, “
Continuum Theory of Ductile Rupture by Void Nucleation and Growth: I. Yield Criteria and Flow Rules for Porous Ductile Media
,”
J. Eng. Mat. Tech.
, Vol.
99
, pp.
2
15
.
18.
Helle
A. S.
,
Easterling
K. E.
, and
Ashby
M. F.
,
1985
, “
Hot Isostatic Pressing Diagrams: New Development
,”
Acta Met.
, Vol.
33
, pp.
2163
2174
.
19.
Hensley
J. E.
,
Risbud
S. H.
,
Groza
J. R.
, and
Yamazaki
K.
,
1993
, “
Plasma-activated Sintering of Aluminum Nitride
,”
Journal of Materials Engineering and Performance
, Vol.
2
, pp.
665
670
.
20.
Hoke
D. A.
,
Meyers
M. A.
,
Meyer
L. W.
, and
Gray
G. T.
,
1992
, “
Reaction Synthesis/Dynamic Compaction of Titanium Diboride
,”
Met. Trans. A.
, Vol.
23A
, pp.
77
86
.
21.
Hutchinson, J. W., 1973, “Finite Strain Analysis of Elastic-Plastic Solids and Structures,” Num. Soln. Nonlin. Struct. Prob., R. F. Hartung, ed., 17, ASME, New York.
22.
Jagota, A., 1992, “Effective Sintering Rates and Viscosities of Two-dimensional Composite Packings,” Mech. of Granular Materials and Powder Systems, ASME-MD 37, New York, pp. 39–50.
23.
Jagota
A.
, and
Dawson
P. R.
,
1988
a, “
Micromechanical Modeling of Powder Compacts—I. Unit Problems for Sintering and Traction Induced Deformation
,”
Acta Metall.
, Vol.
36
, pp.
2551
2561
.
24.
Jagota
A.
, and
Dawson
P. R.
,
1988
b, “
Micromechanical Modeling of Powder Compacts—II. Truss Formulation of Discrete Packings
,”
Acta Metall
, Vol.
36
, pp.
2563
2573
.
25.
Jagota
A.
, and
Dawson
P. R.
,
1990
, “
Simulation of the Viscous Sintering of Two Particles
,”
J. Am. Ceram. Soc
, Vol.
73
, pp.
173
177
.
26.
Jagota
A.
,
Dawson
P. R.
, and
Jenkins
J. T.
,
1988
, “
An Anisotropic Continuum Model for the Sintering and Compaction of Powder Packings
,”
Mech. Mat.
, Vol.
7
, pp.
255
269
.
27.
Jagota
A.
,
Mikeska
K. R.
, and
Bordia
R. K.
,
1990
, “
Isotropic Constitutive Model for Sintering Particle Packings
,”
J. Am. Ceram. Soc.
, Vol.
73
, pp.
2266
2273
.
28.
Kang
E. S.
,
Jang
C. W.
,
Lee
C. H.
, and
Kim
C. H.
,
1989
, “
Effect of Iron and Boron Carbide on the Densification and Mechanical Properties of Titanium Diboride Ceramics
,”
J. Am. Ceram. Soc.
, Vol.
72
, pp.
1868
1872
.
29.
Kostic
E.
,
Kiss
S. J.
,
Boskovic
S.
, and
Cerovic
D.
,
1991
, “
Grain Growth During Liquid Phase Sintering of Al2O3
,”
PMI
, Vol.
23
, pp.
314
316
.
30.
Lange
F. F.
, “
Processing-related Fracture Origins: Observations in Sintered and Isostatically Hot Pressed Al2O3/ZrO2 Composites
,”
J. Am. Ceram. Soc.
, Vol.
31
, pp.
396
398
.
31.
Lawey, A., 1981, “Powder Consolidation, Advances in Powder Technology,” ASM, Metals Park, OH, pp. 75–97.
32.
Lewis
R. W.
,
Jinka
A. G. K.
, and
Gethin
D. T.
,
1993
, “
Computer Aided Simulation of Metal Powder Die Compaction Processes
,”
PMI
, Vol.
25
, pp.
287
293
.
33.
Liniger
E.
, and
Raj
R.
,
1987
, “
Packing and Sintering of Two Dimensional Structures Made from Bimodal Particle Size Distributions
,”
J. Am. Ceram. Soc.
, Vol.
70
, pp
843
849
.
34.
Li
W.-B.
,
Ashby
M. F.
, and
Easterling
K. E.
,
1987
, “
On Densification and Shape Change During Hot Isostatic Pressing
,”
Acta Met.
, Vol.
5
, pp.
2831
2842
.
35.
Liu, C. T., 1993, “Recent Advances on Ordered Intermetallics,” Mat. Res. Soc. Symp. Proc., Vol. 288, pp. 3–19.
36.
Mabuchi
H.
,
Harada
K.
,
Tsuda
H.
, and
Nakayama
Y.
,
1991
, “
Fabrication of Ti2AlC/TiAl Composites Using Combustion Reaction Process
,”
ISIJ Int.
, Vol.
31
, pp.
1272
1278
.
37.
Matsuo
M.
,
1991
, “
Developments in Processing Technology of Gamma Titanium Aluminides for Potential Applications to Airframe Structures
,”
ISIJ Int.
, Vol.
31
, pp.
1212
1222
.
38.
McMeeking
R. M.
,
1991
, “
Consolidation of Powder to Form a Matrix Around Fibers in a Composite Material
,”
Mech. Mat.
, Vol.
12
, pp.
185
190
.
39.
McMeeking
R. M.
,
1992
a, “
The Analysis of Shape Change During Isostatic Pressing
,”
Int. J. Mech. Sci.
, Vol.
34
, pp.
53
62
.
40.
McMeeking, R. M., 1992b, “Constitutive Laws for Sintering and Pressing of Powders,” Mech. of Granular Materials and Powder Systems, ASME-MD 37, New York, pp. 51–61.
41.
Mori
K.
, and
Osakada
K.
,
1987
, “
Analysis of the Forming Process of Sintered Powder Metals by a Rigid Plastic Finite Element Method
,”
Int. J. Mech. Sci.
, Vol.
29
, pp.
229
238
.
42.
Nagtegaal
J. C.
,
Parks
D. M.
, and
Rice
J. R.
,
1974
, “
On Numerically Accurate Finite Element Solutions in the Fully Plastic Range
,”
Comp. Meth. Appl. Mech. Engrg.
, Vol.
4
, pp.
153
177
.
43.
Oden
J. T.
, and
Martins
J. A. C.
,
1985
, “
Models and Computational Methods for Dynamic Friction Phenomena
,”
Comp. Meth. Appl. Mech.
, Vol.
52
, pp.
527
634
.
44.
Ogbonna
N.
, and
Fleck
N. A.
,
1995
, “
Compaction of an Array of Spherical Particles
,”
Acta Met. Mat.
, Vol.
43
, pp.
603
620
.
45.
Panda
P. C.
,
Lagraff
J.
, and
Raj
R.
,
1988
, “
Shear Deformation and Compaction of Nickel Aluminide Powders at Elevated Temperatures
,”
Acta. Metall.
, Vol.
36
, pp.
1929
1939
.
46.
Panda
P. C.
, and
Seydel
E. R.
,
1986
, “
Near Net Shape Forming of Magnesia-Alumina Spinel/Silicon-Carbide Fiber Composites
,”
Am. Ceram. Soc. Bull.
, Vol.
65
, pp.
338
341
.
47.
Panda
P. C.
,
Wang
J.
, and
Raj
R.
,
1988
, “
Sinter-Forging Characteristics of Fine Grained Zirconia
,”
J. Am. Ceram. Soc.
, Vol.
71
, pp.
C507–C509
C507–C509
.
48.
Petzi
F.
,
1989
, “
20 Years of P/M Sintering
,”
PMI
, Vol.
21
, pp.
29
36
.
49.
Rahman
M. N.
,
DeJonghe
L. C.
, and
Brook
R. J.
,
1986
, “
Effect of Shear Stress on Sintering
,”
J. Am. Ceram. Soc
, Vol.
69
, pp.
53
58
.
50.
Rahman
M. N.
,
DeJonghe
L. C.
,
Scherer
G. W.
, and
Brook
R. J.
,
1987
, “
Creep and Densification During Sintering of Glass Powder Compacts
,”
J. Am. Ceram. Soc
, Vol.
70
, pp.
766
774
.
51.
Ren, F., Chandra, A., and Tvergaard, V., 1994, “A Unit Cell Analysis of Ti-Al Powder Compaction at Elevated Temperatures,” Mechanics in Materials Processing, ASME, AMD-194, pp. 239–260.
52.
Ren, F., 1995, “Micromechanical Study of Ti-Al Powder Processing,” MS Report, Univ. of Arizona.
53.
Scherer, G. W., 1992, “Constitutive Models for Viscous Sintering,” Mech. of Granular Materials and Powder Systems, ASME-MD 37, New York, pp. 1–18.
54.
Shang
S.-S.
, and
Meyers
M. A.
,
1991
, “
Shock Densification/hot Isostatic Pressing of Titanium Aluminide
,”
Met. Trans. A.
, Vol.
22A
, pp.
2667
2676
.
55.
Selkregg
K. R.
,
More
K. L.
,
Seshadri
S. G.
, and
McMurty
C. H.
,
1990
, “
Microstructural Characterization of Silicon Nitride Ceramics Processed by Pressureless Sintering, Overpressure Sintering and Sinter HIP
,”
Ceram. Eng. Sci. Proc.
, Vol.
11
, pp.
603
615
.
56.
Smelser, R. E., Zarzour, J. F., Xu, J., and Trasorras, J. R. L., 1994, “On the Modeling of Near-Net Shape Hot Isostatic Pressing,” Mechanics in Materials Processing, AMD-vol. 194, ASME, New York.
57.
Svoboda, J., and Riedel, H., 1992, “Evolution Equations for the Grain Size During Sintering,” Mech. of Granular Materials and Powder Systems, ASME-MD 37, New York, pp. 29–38.
58.
Swinkels, F. B., and Ashby, M. F., 1981, “A Second Report on Sintering Diagrams,” Vol. 29, pp. 259–281.
59.
Tvergaard, V., 1989, “Material Failure by Void Growth to Coalescence,” Advances in Applied Mechanics, Vol. 27, Academic Press, San Diego, pp. 83–151.
60.
Van der Giessen
E.
, and
Tvergaard
V.
,
1991
, “
A Creep Rupture Model Accounting for Cavitation at Sliding Grain Boundaries
,”
Int. J. Fracture.
, Vol.
48
, pp.
153
178
.
61.
Vecchio
K. S.
,
LaSalvia
J. C.
,
Meyers
M. A.
, and
Gray
G. T.
,
1992
, “
Microstructural Characterization of Self-Propagating High-Temperature Synthesis/Dynamically Compacted and Hot Pressed Titanium Carbides
,”
Met. Trans., A.
, Vol.
23A
, pp.
87
97
.
62.
Venkatachari
K. R.
, and
Raj
R.
,
1986
, “
Shear Deformation and Densification of Powder Compacts
,”
J. Am. Ceram. Soc.
, Vol.
69
, pp.
499
506
.
63.
Venkatachari
K. R.
, and
Raj
R.
,
1987
, “
Enhancement of Strength Through Sinter Forging
,”
J. Am. Ceram. Soc.
, Vol.
70
, pp.
514
520
.
64.
Wang
G.-X.
, and
Dahms
M.
,
1992
, “
An Overview: TiAl-Based Alloys Prepared by Elemental Powder Metallurgy
,”
PMI
, Vol.
24
, pp.
219
225
.
65.
Wang
J.
, and
Raj
R.
,
1991
, “
Interface Effects in Superplastic Deformation of Alumina Containing Zirconia, Titania or Hafnia as a Second Phase
,”
Acta Metall. Mater.
, Vol.
39
, pp.
2909
2919
.
66.
Wang, P. T., and Richmond, O., 1992, “Overview of a Two State Variable Constitutive Model for the Consolidation and Forming Processes of Powder-Based Porous Metals,” Mech. of Granular Materials and Powder Systems, ASME-MD 37, New York, pp. 62–83.
67.
Wriggers
P.
,
Vu Van
T.
,
Stein
T.
, and
Stein
E.
,
1990
, “
Finite Element Formulation of Large Deformation Impact-Contact Problems With Friction
,”
Computers and Structures
, Vol.
37
, pp.
319
331
.
68.
Yu
L.-H.
,
Meyers
M. A.
, and
Peng
T. C.
,
1991
, “
Shock Consolidation of Al-Li Alloy Powders
,”
Mat. Sc. Eng.
, Vol.
A132
, pp.
257
265
.
69.
Zavarise
G.
,
Wriggers
P.
,
Stein
E.
, and
Schrefler
B. A.
,
1992
, “
Real Contact Mechanisms and Finite Element Formulation—A Coupled Thermomechanical Approach
,”
Int. J. Num. Meth. Engng.
, Vol.
35
, pp.
767
785
.
70.
Zienkiewicz, O. C., and Taylor, R. L., 1989, The Finite Element Method, McGraw Hill, London.
This content is only available via PDF.
You do not currently have access to this content.