Electrical conductivity of copper and tin in the region of a low density and a high specific energy

The electrical conductivities of high-porosity copper and tin samples are measured during shock compression at a low density and a high specific energy of a substance. The dependences of electrical conductivity on the shock pressure are constructed for a copper powder with a density of 0.76 g/cm$^3$ (porosity coefficient of 11.8) and for tin powders with a density of 1.9 and 4.8 g/cm$^3$ (porosity coefficients of 3.9 and 1.5). These dependences are nonmonotonic. At a high pressure, the electrical conductivities of the copper and tin powders weakly depend on the shock pressure. At a pressure $p>$ 2 GPa, the electrical conductivity of the copper powder agrees satisfactorily with the Bakulin model.