Mullite composites mechanical properties

Most structural PMCs consist of a relatively soft matrix, such as a thermosetting plastic of polyester, phenolic, or epoxy, sometimes referred to as resin-matrix composites. Some typical polymers used as matrices in PMCs are listed in Table 1.28. The list of metals used in MMCs is much shorter. Aluminum, magnesium, titanium, and iron- and nickel-based alloys are the most common (see Table 1.29). These metals are typically utilized due to their combination of low density and good mechanical properties. Matrix materials for CMCs generally fall into fonr categories glass ceramics like lithium aluminosilicate oxide ceramics like aluminnm oxide (alnmina) and mullite nitride ceramics such as silicon nitride and carbide ceramics such as silicon carbide. 

Marple, B.R. Green, D.J. (1991) Mullite/alumina particulate composites by infiltration processing III, Mechanical properties. J. Am. Ceram. Soc. 74, 2453-2459. 

Whereas the ambient mechanical properties have been studied extensively, the high temperature properties of mullite and mullite/zirconia matrix composites have been examined by only a few studies.18 30,32 34... 

Mouchon, E., and Colomban, R, Microwave absorbent preparation, mechanical properties and RF/microwave conductivity of SiC (and/or mullite) fibres reinforced NASICON matrix composites, J. Mater. ScL, 31, 323, 1996. 

Keywords Si-Al-Zr-O amorphous bulk crystallization, Zirconia-mullite composite structure, mechanical property... 

Recently, some other non- conventional ways have been used to prepare zirconia-mullite ceramics [12-17]. In our previous work, nano-zirconia/mullite composite ceramics were prepared by in-situ controlled crystallization from the Si-Al-Zr-0 amorphous bulk, the crystallization kinetics and the general view on the performance were discussed for the first time. In this article, the detail crystallization behavior, structure changes and their effect on mechanical properties for this new nano composite ceramics with high performance have been evaluated. 

E. Mouchon, and P. H, Colomban, Microwave Absorbent Preparation, Mechanical Properties and r. f-microwave Conductivity of SiC (and/or mullite) Fibre Reinforced Nasicon Matrix Composites, J. Mater Sc/., 31(2), 323-334 (1996),... 

This section centers on fiber coatings for non-oxide eomposites in which either the fiber or the matrix is a non-oxide ceramic. Although oxide fiber-reinforced composites have been studied, most of the research available in the literature has focused on SiC fiber-reinforced composites. For example, mullite (3Al203-2Si02) fiber-reinforced SiC matrix composites have been fabricated by CVI (chemical vapor infiltration). However, SiC fiber-reinforced SiC matrix (SiC/SiC) composites are superior for the following reasons (1) mullite fiber-reinforced composites do not improve resistance to oxidation, one of the major factors limiting the use of non-oxide composites and (2) SiC fibers have mechanical properties superior to those of mullite fibers. This section will be concerned primarily with SiC fiber-reinforced ceramic composites, which offer the best oxidation resistance of any non-oxide fiber at high temperatures (particularly above 1,100°C [2012°F]). 

N. Claussen and J. Jahn, Mechanical Properties of Sintered, In situ-Reacted Mullite-Zirconia Composites, J.Am. Ceram. Soc., 63 [3 ] 228-29 (1980). 

G. Orange, G. Fantozzi, F. Cambier, C. Leblud, M. R. Anseau, and A. Leriche, High Temperature Mechanical Properties of Reaction-Sintered MulUte/Zirconia and Mullite-AluminayZirconia Composites, /. Mater. Sci., 20 [7] 2533 0 (1985). 

Y. Hirata, S. Matsushita, Y. Ishihara, H. Katsuki, Colloidal processing and mechanical properties of whisker-reinforced mullite matrix composites, 7. Am. Ceram. Soc. 74 2438-2442(1991). 

Magnesium aluminosilicate glass composites with 3-D mullite whisker reinforcement Fracture strength 330 MPa. Fracture toughness 3.3 MPam Structural applications requiring isotropic mechanical properties [30]... 

Travitzky, N. A., Mechanical Properties and Microstmcture of Mullite Whisker-Reinforced Magnesiitm Aluminosilicate Glass with Cordierite Composition, 7. Mat. Sci. Lett. 17 (1998) 1609-1611. 

Claussen and Jahn ° were the Erst researchers to show that the mechanical properties of mullite could be improved by the dispersion of zirconia particles. Fracture toughness improved from 2.0 to 4.5 MPa-ml4 and the strength doubled to 400 MPa. They were able to fabricate the dense (>98% theoretical density (T.D.)) mullite-zirconia composite at relatively low sintering temperatures of 1575-1600 °C by the in-silu reaction of alumina and zircon to form mullite with approximately 25 vol% zirconia ... 

M. lshitsuka,T. Sato, T. Endo, and M. Shimada, Sintering and Mechanical Properties of Yttria-Doped Tetragonal ZrOi Polycrystal/Mullite Composites, 7. Am. Ceram. Soc., 70, C-342-C-346 (1987). 

K. Das and G. Banerjee, Mechanical Properties and Microstmctures of Reaction-Sintered Mullite-ZrOa Composites in the Presence of an Additive- Dysprosia,7. Ear. Ceram. Soc., 20,153-157 (2000). J.S. Moya and M.l. Osendi, Effect of ZrOa (ss) in Mullite on the Sintering and Mechanical Properties of Mullite/ZrOa Composites, 7. Mat. Sci. Lett., 2, 599-601 (1983). 

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