Mechanical Properties of α-Solid Solutions of Copper, with Zinc, Gallium, Germanium and Arsenic

Abstract

THE strengthening of metals by alloying elements in solid solution is often attributed to the local distortions of the lattice due to the difference in size between the solute atoms and the solvent atoms. In 1942¹, Hume-Rothery and Frye showed that in a series of silver alloys the ultimate Meyer hardness brought about by a given percentage of solute atoms was proportional to the square of the lattice distortion for solutes in the same row of the Periodic Table. In 1950, Dorn, Pietrokowsky and Tietz² published the results of tensile tests on a series of aluminium alloys, and showed that the increase in strength was not attributable solely to the lattice strain; but that effects due to the difference in valency between solvent and solute must be taken into account. Thus, they suggest that the hardness of the alloys is given by the equation F = ▵a + K▵v, where F is hardness; ▵a is change in lattice constant; ▵v is (atomic per cent solute)/100 × (valency of solute − valency of solvent); K is constant (approximately 1). In their work the unexpected valency of 2 was assigned to aluminium.