Portal de Periódicos da CAPES

The effect of interfacial reaction on thermal properties of titanium reinforced with particulate SiC

1991; Elsevier BV; Volume: 141; Issue: 1 Linguagem: Inglês

10.1016/0921-5093(91)90716-z

1873-4936

Andrew James Reeves, Rex N. Taylor, T.W. Clyne,

Thermal properties of materials

Abstract The thermal diffusivity, and hence the thermal conductivity, of titanium reinforced with 10 vol.% of particulate SiC has been measured over a range of temperature (up to 560°C) and as a function of the thickness of the reaction product mixture (TiC + Ti 5 Si 3 ) formed at the interface. It was found that, provided the reaction layer was thin (less than about 0.5 μm), the conductivity of the composite was similar to that of unreinforced titanium. The data are examined in the light of predictions from the Eshelby equivalent homogeneous inclusion approach and the Hasselman and Johnson model. The observed conductivity compares with a larger value expected if the SiC particles had a high thermal conductivity (typical of previously reported values for dense bulk specimens) and there was no interfacial thermal resistance, and with a smaller value expected if the SiC particles were carrying no heat flux. Specimens with a thick interfacial reaction layer were found to exhibit a thermal conductivity lower even than that expected for insulating particles, although the reduction was less marked at higher temperatures. This is attributed to the effect of cracks and porosity caused by the reaction, which raises the interfacial thermal resistance and the effective size of the particles. Thermal expansivity data are also presented, showing relatively high values for the heavily reacted composites. These observations highlight the need to keep the reaction layer as thin as possible in these composites.