Elastic Constants ofα-Brasses: Room-Temperature Variation with Solute Concentration

Room-temperature elastic constant measurements have been made on a representative series of $\alpha$-brasses. The variation with solute concentration of the shear constant $C$ suggests that there is an appreciable contribution to it resulting from the onset of overlap between the Fermi surface and the {111} faces of the Brillouin zone. There is reasonable agreement between the experimentally determined magnitude of this contribution and that predicted from theory. According to the latter, there should be no corresponding contribution to the shear constant $C^{\prime }$, which prediction appears to be in accordance with experiment.