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| TiB2-Cu ceramic-metal composites were prepared by combustion synthesis of elemental titanium, boron and copper powders. The synthesized product consisted of two phases: TiB2 and copper. The addition of copper improved the strength and fracture toughness, thermal expansion coefficient and thermal conductivity of TiB2. Thermal shock and ablation resistances of TiB2-Cu composites were studied using a plasma torch arc heater. Monolithic TiB2 failed catastrophically when the plasma arc flow reached the specimen surface. However, no cracks were found on the ablation surface of the TiB2-Cu ceramic-metal composites. The fractional mass loss was 4.09 % for a TiB2-40Cu composite, which was close to the traditional W/Cu alloys. Volatilization of metal binder and mechanical erosion of TiB2 were observed to be the major ablation mechanisms. An ablation process model is proposed for the TiB2-Cu composites. |
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| Keywords:TiB2-Cu ceramic-metal composite, combustion synthesis, microstructure, thermal shock resistance, ablation mechanisms |
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