Combustion synthesis of metal-matrix composites. Part 1: The Ti-TiC-Al{sub 2}O{sub 3} system
- UFRGS, Porto Alegre, Rio Grande do Sul (Brazil). Dept. de Metalurgia
- Colorado School of Mines, Golden, CO (United States). Dept. of Metallurgical and Materials Engineering
Combustion synthesis or Self-propagating High-temperature Synthesis (SHS) is a process that involves a reaction which is sufficiently exothermic to sustain itself, and, as such, provides considerable potential for the development of an affordable (low cost), energetically efficient means of producing advanced materials. In the combustion synthesis process, a mix of the reactant powders, pressed into a pellet, is heated to the ignition temperature, Tig, when the exothermic reaction takes place, transforming reactants into products. The heat generated by the reaction raises the temperature of the products to a maximum recorded combustion temperature, Tc, which, under adiabatic conditions, would be the adiabatic temperature, Tad. However, in most combustion reactions, Tc is less than Tad, since heat losses occur from the reaction front. Materials synthesized with each of these combustion modes are typically associated with high levels of porosity, e.g., 50%, which is manifested as both macroporosity and microporosity. Previous work demonstrated that it was possible to decrease the porosity of a TiC-Al{sub 2}O{sub 3}-Ti composite by incorporating an excess liquid metal into the combustion synthesis reaction system. This reaction utilizes aluminothermic reduction of TiO{sub 2} to generate the exothermic condition, and at the same time, uses the required TiO{sub 2}/Al stoichiometry to provide the excess Ti to generate an excess Ti in a matrix of TiC and Al{sub 2}O{sub 3}, each of which are synthesized, in-situ within the overall reaction system.
- OSTI ID:
- 186787
- Journal Information:
- Scripta Materialia, Journal Name: Scripta Materialia Journal Issue: 2 Vol. 34; ISSN 1359-6462; ISSN XZ503X
- Country of Publication:
- United States
- Language:
- English
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