On equilibrium point defects in metals

It is shown that the point-defect contribution to the electrical resistivity of tungsten can be seen also from measurements under equilibrium. The defect contribution at the melting point is estimated as 5 × 10^-7 Ω cm. The high entropies of vacancy formation deduced earlier from the nonlinear increase in the high-temperature specific heat are consistent with the bounds of thermodynamic origin and agree with self-diffusion data. The temperature dependence of the enthalpies of vacancy formation in metals is calculated assuming a linear temperature dependence of the formation entropy. A brief summary of present knowledge about point defects in metals is given. Experimental and theoretical results obtained during the last decade support equilibrium defect concentrations based on the nonlinear increase in the high-temperature specific heat of metals.