THE INFLUENCE OF DELTA'-PRECIPITATES ON THE ELECTRICAL-RESISTIVITY AND LOW-FIELD HALL-COEFFICIENT OF AL-LI ALLOYS

Measurements of the electrical resistivity in the temperature range 4. 2-300 K and of the Hall coefficient at 4.2 K have been performed on an Al Li alloy of 8 at.% Li concentration. Information on the microstruc ture of aged alloy were obtained from transmission electron microscopy . As the mean size of the delta' precipitates increases, the electric al resistivity at 4.2 K decreases, while the low-field Hall coefficien t increases with a tendency to saturate. This behaviour can be explain ed qualitatively considering the anisotropic scattering of the electro ns both on the delta' precipitates and the randomly distributed Li ato ms in the matrix. The temperature dependence of the phonon resistivity of the aged alloy varies as T(n), where 0.5 < n < 3.5.