Effects of porosity on the thermal properties of a 380-aluminum alloy

Effective values of the thermal diffusivity, specific heat, and thermal con ductivity of a porous 380-aluminum alloy prepared by melting in a gas-fired furnace, were determined as a function of the volume fraction of porosity. For that, photoacoustic, differential calorimetric, density, and image ana lyzer measurements were done. Thermal conductivity and specific heat capaci ty decrease with the increase of porosity, whereas the thermal diffusivity shows less dependence. Among the effective models for analysis of the therm al conductivity of a two-phase system, the Maxwell model best fits the expe rimental data, implying a homogenous distribution of the pores in the alumi num-alloy matrix.