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Thesis
Synthesis and characterization of the properties of Ti₃SiC₂/SiC and Ti₃SiC₂/TiC composites
Master of Science (M.S.), Drexel University
Jan 2002
DOI:
https://doi.org/10.17918/etd-54
Abstract
In 1996, the ternary compound titanium silicon carbide (Ti₃SiC₂) was for the first timesynthesized as a single-phase, fully dense compound. Its characterization revealed aunique combination of properties. For its high fracture toughness, low hardness toelastic modulus ratio and excellent damage tolerance, it was dubbed a soft ceramic. Italso displayed good thermal shock and oxidation resistance. In this work, thereinforcement of this material with silicon carbide and titanium carbide particles wasexplored with the intention of improving mechanical and oxidation properties. Thecomposites were synthesized by HIPing of starting powders, following the sameprocessing as for pure Ti₃SiC₂. It was found that the particles affected the microstructureof the Ti₃SiC₂ matrix, reducing the grain size of a material that otherwise would havebeen coarse-grained. Mechanical properties of the composites were investigated throughfour-point bend tests and Vickers indentations. The flexural strength of the compositeswas lower than expected from the grain size of the matrix and was explained by athermal expansion coefficient mismatch. Fracture toughness of the composites was alsolower than for Ti₃SiC₂. However, the hardness and damage tolerance were improved. Oxidation experiments were conducted in air at temperatures ranging between 875°C and 1220°C. The oxidation behavior of the Ti₃SiC₂/SiC composite was found to besubparabolic at 925°C, but from 1010°C to 1220°C, it was parabolic with a transition tolinear behavior. The oxidation of the Ti₃SiC₂/TiC composite was parabolic at 875°C, andfrom 975°C to 1220°C, showed the same behavior as the other composite. The growth ofthe oxide scale of the composites was fitted with a multiple-law model. It wasdetermined that the oxidation of the composites occurred by diffusion of oxygen inwardand titanium outward. The parabolic component of the oxide scale growth was found tocorrespond to the diffusion of oxygen inward, as in pure Ti₃SiC₂. The correspondingparabolic constants were found to be lower for Ti₃SiC₂/SiC and higher for Ti₃SiC₂/TiC,compared to the pure material.
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Details
- Title
- Synthesis and characterization of the properties of Ti₃SiC₂/SiC and Ti₃SiC₂/TiC composites
- Creators
- Linh H. Ho-Duc - DU
- Contributors
- Michel W. Barsoum (Advisor) - Drexel University (1970-)Tamer S. El-Raghy (Advisor) - Drexel University (1970-)
- Awarding Institution
- Drexel University
- Degree Awarded
- Master of Science (M.S.)
- Publisher
- Drexel University; Philadelphia, Pennsylvania
- Resource Type
- Thesis
- Language
- English
- Academic Unit
- Materials (Science and) Engineering (Metallurgical Engineering) [Historical]; College of Engineering (1970-2026); Drexel University
- Other Identifier
- 54; 991014632386604721