IX. A calculation of the elastic shear constants of ?-brass

Abstract

The stability of β-brass, with respect to shears across the (110) plane in the direction [110], is considered and is shown to be due, mainly, to the change of the Fermi energy as a result of the shearing of the Brillouin zone. Calculations are made which show that this effect contributes approximately 10¹¹ dynes/cm² to the shear constant 1/2(c ₁₁-c ₁₂), and a rather larger amount to c₄₄. The constitution of the elastic shear constants, as the sum of three terms, is examined and a satisfactory account of the observed values is obtained. The difficulty experienced in attempting to retain the β-phases by quenching is briefly discussed.