Abstract
Heating the specimens of aluminium-silver alloy which are in thermal equilibrium, from the room temperature to above the two phase boundary, the changes of specific heat and electrical resistance have been examined: from the characteristic changes of them due to the resolution of precipitated phase, the solid solubility curve or “solvus” of silver in aluminium has been determined.
A remarkable change in the direction of the solvus at about 20 atomic percentage of silver and at 526°C which was for the first time observed by Raynor and Wakeman through their micrographic examination, has been reconfirmed.
Besides, the energy of solid solution and accompanied entropy change have been determined and shown plotted against silver content from 1.3 to 50 atomic %. Both curves show a bending which is probably attributable to the effect of the electronic band structure of pure aluminium metal.
The energy of valence electrons in the solid solutions has been calculated by means of the state density curve due to Matyáš, Axon and Hume-Rothery. It was found: In order to explain the observed increasing of the energy of alloys, it seems that aluminium must have 2.5 electrons per atom but not three.
